357 results on '"Margaret Ip"'
Search Results
202. Comparative Study of Nasopharyngeal Aspirate and Nasal Swab Specimens for Diagnosis of Acute Viral Respiratory Infection
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Tracy Tsen, Kai Chow Choi, Apple C.M. Yeung, Rita Y T Sung, Paul K.S. Chan, E. Anthony S. Nelson, Albert M. Li, Julian W. Tang, and Margaret Ip
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Male ,Microbiology (medical) ,Virus Cultivation ,viruses ,Fluorescent Antibody Technique ,Mucous membrane of nose ,Respiratory Syncytial Virus Infections ,Biology ,Polymerase Chain Reaction ,Sensitivity and Specificity ,Virus ,Specimen Handling ,Adenovirus Infections, Human ,stomatognathic system ,Nasopharyngeal aspirate ,Nasopharynx ,Virology ,Influenza, Human ,Humans ,Respiratory Tract Infections ,Paramyxoviridae Infections ,Respiratory tract infections ,Viral culture ,Respiratory infection ,Nasal Mucosa ,Nasal Swab ,Child, Preschool ,Female ,Viral disease - Abstract
Paired nasopharyngeal aspirate (NPA) and nasal swab (NS) samples from 475 children hospitalized for acute respiratory infection were studied for the detection of influenza virus, parainfluenza virus, respiratory syncytial virus, and adenovirus by immunofluorescence test, viral culture, and multiplex PCR assay. The overall sensitivity of viral detection with NPA specimens was higher than that obtained with NS specimens.
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- 2008
203. Atopic Dermatitis Complicated by Methicillin-Resistant Staphylococcus aureus Infection
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Kam-Lun Ellis, Margaret Ip, Ting-Fan Leung, Alexander K. C. Leung, and Albert Y.F. Kong
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Male ,Staphylococcus aureus ,medicine.medical_specialty ,Allergy ,Adolescent ,Exacerbation ,Erythema ,medicine.disease_cause ,Dermatitis, Atopic ,Atopy ,medicine ,Humans ,Generalized erythema ,Child ,Retrospective Studies ,business.industry ,General Medicine ,Atopic dermatitis ,Staphylococcal Infections ,medicine.disease ,Dermatology ,Methicillin-resistant Staphylococcus aureus ,body regions ,Vancomycin ,Female ,Methicillin Resistance ,medicine.symptom ,business ,medicine.drug - Abstract
Introduction S taphylococcus aureus colonization/infection is commonly associated with disease severity in children with atopic dermatitis. The present report is a three-year retrospective chart review of five cases (comprising three boys and two girls, aged 9–15 years at referral) of methicillin-resistant S. aureus (MRSA) in children with moderate-to-severe atopic dermatitis. The review period spanned 2004–2007. All had longstanding severe disease, high IgE and eosinophil counts. Generalized erythema and a peculiar fishy odor were frequently observed by parents and physicians when MRSA was isolated during some of the episodes of exacerbation. All had tried various combinations of topical and systemic steroids, topical immunomodulants, traditional Chinese medicine and courses of antibiotics—without lasting relief. All specimens of MRSA had in-vitro sensitivity to vancomycin, with corresponding clinical correlates of disappearance of the erythema and fishy odor. Conclusion A fishy odor and facial/generalized erythema in a patient with atopic dermatitis should alert the physician to screen for MRSA. The organism is rarely isolated, even among children with moderate-to-severe atopic dermatitis, and is usually sensitive to vancomycin.
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- 2008
204. Adsorption of Amikacin, a Significant Mechanism of Elimination by Hemofiltration
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Perpetua E. Tan, Qi Tian, Margaret Ip, Gordon Y.S. Choi, Charles D. Gomersall, and Gavin M. Joynt
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medicine.medical_treatment ,Acrylic Resins ,Repeated dosing ,Hemoglobins ,chemistry.chemical_compound ,Adsorption ,Albumins ,Hemofiltration ,medicine ,Humans ,Pharmacology (medical) ,Amikacin ,Antibacterial agent ,Pharmacology ,Chromatography ,Polyacrylonitrile ,Membranes, Artificial ,Anti-Bacterial Agents ,Nylons ,Infectious Diseases ,Continuous venovenous hemofiltration ,chemistry ,Saturation (chemistry) ,medicine.drug - Abstract
We used an in vitro model of continuous venovenous hemofiltration (CVVH) to characterize amikacin adsorption by polyacrylonitrile (PAN) and polyamide filters. A blood-crystalloid mixture dosed with amikacin was pumped from a reservoir through a hemofiltration circuit and back to the reservoir. All ultrafiltrate was also returned to the reservoir. The level of adsorption was calculated from the fall in the amikacin concentration. The dose and the initial concentration of amikacin were varied, as were the pH, the type of hemofilter, and the hemofilter surface area. The reversibility of adsorption and the effect of repeated dosing were also studied. The level of adsorption by 0.6-m 2 PAN filters was significantly greater than that by 0.6-m 2 polyamide filters. Adsorption was increased by increasing the dose of amikacin even when the initial concentration was unchanged. It was unaffected by the pH (pH 6.8 or 7.4) or the hemofilter surface area (0.6 m 2 or 0.9 m 2 ). Repeated doses of amikacin resulted in further adsorption. In a saturation experiment, the maximum adsorptive capacity of 0.6-m 2 PAN hemofilters was at least 546.9 mg (range, 427.6 to 577.5 mg). The adsorption of amikacin by hemofilters is irreversible and was associated with the dose and the hemofilter material but not the hemofilter surface area. Close monitoring of peak amikacin levels should be considered for patients receiving CVVH with PAN hemofilters.
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- 2008
205. Crossing the barrier: Evolution and spread of a major class of mosaic pbp2x in Streptococcus pneumoniae, S. mitis and S. oralis
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Margaret Ip, Regine Hakenbeck, Oliver Nolte, Fang Chi, and Carina Bergmann
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DNA, Bacterial ,Microbiology (medical) ,Penicillin binding proteins ,Penicillin Resistance ,Streptococcus mitis ,Penicillins ,medicine.disease_cause ,Microbiology ,Streptococcus pneumoniae ,medicine ,Penicillin-Binding Proteins ,Crossing Over, Genetic ,Typing ,Gene ,Genetics ,Streptococcus pseudopneumoniae ,biology ,Streptococcus ,Streptococcus oralis ,General Medicine ,biology.organism_classification ,Infectious Diseases - Abstract
A paradigm for Streptococcus interspecies gene transfer is represented by the mosaic pbp genes encoding the target enzymes for beta-lactam antibiotics, the penicillin-binding proteins, in Streptococcus pneumoniae. We investigated a collection of oral streptococci from three continents by comprehensive multi-locus sequence typing analysis in order to trace the origin of a mosaic block belonging to a dominant family of mosaic pbp2x implicated in penicillin resistance of S. pneumoniae. One widespread family of mosaic pbp2x occurred in all three distinct clusters of S. pneumoniae, Streptococcus mitis and Streptococcus oralis, documenting independent inter- and intraspecies recombination events. Moreover, potential ancestor genes of this mosaic block could be identified in two penicillin-susceptible S. mitis strains from South Africa and Spain, facilitating the identification of pbp2x mutations relevant for resistance development.
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- 2007
206. Value of serum procalcitonin, neopterin, and C-reactive protein in differentiating bacterial from viral etiologies in patients presenting with lower respiratory tract infections
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Tze Kin Tam, Shirley S.L. Chau, Reinhard Renneberg, Tze Kin Lau, Wingman Leung, Cangel Chan, Grace Lui, Nelson Lee, Man Fai Leung, David S.C. Hui, Dietmar Fuchs, Gregory E. Antonio, Paul K.S. Chan, Margaret Ip, and Timothy H. Rainer
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Adult ,Calcitonin ,Male ,Microbiology (medical) ,Calcitonin Gene-Related Peptide ,Neopterin ,Sensitivity and Specificity ,Procalcitonin ,chemistry.chemical_compound ,medicine ,Humans ,Protein Precursors ,Respiratory Tract Infections ,Aged ,Aged, 80 and over ,Receiver operating characteristic ,Respiratory tract infections ,biology ,business.industry ,C-reactive protein ,Respiratory disease ,Bacterial Infections ,General Medicine ,Middle Aged ,medicine.disease ,Pneumonia ,C-Reactive Protein ,Infectious Diseases ,ROC Curve ,chemistry ,Virus Diseases ,Immunology ,biology.protein ,Etiology ,Female ,business ,Biomarkers - Abstract
The values of procalcitonin (PCT), neopterin, and C-reactive protein (CRP) alone and in combination to differentiate bacterial from viral etiology in patients with lower respiratory tract infections (LRTIs) were evaluated. Sera obtained on the day of hospitalization for LRTI from 139 patients with confirmed bacterial etiology and 128 patients with viral etiology were examined. A further 146 sera from healthy Chinese subjects with no infection were included as controls. The area under the receiver operating characteristic (ROC) curve (area under curve [AUC]) for distinguishing bacterial from viral infections was 0.838 for CRP and 0.770 for PCT (P < 0.05). The AUC for distinguishing viral from bacterial infections was 0.832 for neopterin (P < 0.05). When the markers were used in combination, AUC of ROC (CRP/neopterin) was 0.857, whereas (CRP × PCT)/neopterin was 0.856. Combination of 2 or all 3 of the biomarkers may improve the discriminatory power in delineating bacterial versus viral etiology in LRTI.
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- 2007
207. Viral Etiology of Acute Exacerbations of COPD in Hong Kong
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David S.C. Hui, Michael C.H. Chan, Kin Wang To, Margaret Ip, Shirley S.L. Chau, Paul K.S. Chan, Susanna S.S. Ng, Fanny W.S. Ko, and Julian W. Tang
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Male ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,viruses ,Critical Care and Intensive Care Medicine ,medicine.disease_cause ,Polymerase Chain Reaction ,Article ,Positive-Pressure Respiration ,Pulmonary Disease, Chronic Obstructive ,FEV1/FVC ratio ,GOLD, Global Initiative for Chronic Obstructive Lung Disease ,PCR, polymerase chain reaction ,MDCK, Mardin Darby canine kidney ,Forced Expiratory Volume ,Nasopharynx ,Internal medicine ,medicine ,COPD ,Humans ,RNA Viruses ,Prospective Studies ,acute exacerbation ,Aged ,Coronavirus ,Aged, 80 and over ,business.industry ,Viral culture ,AECOPD, acute exacerbations of COPD ,medicine.disease ,Viral Identification ,Virology ,Hospitalization ,NPA, nasopharyngeal aspirate ,Acute Disease ,Etiology ,Hong Kong ,Female ,CXR, chest radiograph ,RSV, respiratory syncytial virus ,Viral disease ,NPPV, noninvasive positive pressure ventilation ,Rhinovirus ,Cardiology and Cardiovascular Medicine ,business ,Follow-Up Studies - Abstract
Introduction Viral respiratory infections may precipitate acute exacerbations of COPD (AECOPD). However, little is known about viral etiology related to AECOPD in Asia. We aimed to study the viral etiology of AECOPD in Hong Kong. Methods Patients admitted to an acute hospital in Hong Kong with AECOPD were recruited prospectively from May 1, 2004, to April 30, 2005. Nasopharyngeal aspirate was collected and assessed by polymerase chain reaction (PCR) and viral culture. Spirometry was performed in the stable phase at 2 to 3 months after hospital discharge. Results There were 262 episodes of AECOPD among 196 patients (mean age, 75.7 ± 7.7 years [± SD]; 160 men). Mean FEV1 was 39.6 ± 18.9% of predicted normal, and FEV1/FVC ratio was 58.0 ± 15.2%. Fifty-eight episodes (22.1%) yielded positive viral PCR results. The viruses identified were influenza A (7.3%), coronavirus OC43 (4.6%), rhinovirus (3.1%), influenza B (2.7%), and respiratory syncytial virus (2.3%). The diagnostic yield of viral identification by PCR was 2.7 times higher than that based on conventional viral culture. The rates of identifying a positive viral etiology by PCR were similar among the subjects with FEV1 ≥ 50%, ≥ 30 to 50%, and < 30% of predicted normal. Viral infection appeared to have no effect on subsequent readmissions or mortality rate over a study period of 1 year Conclusion Influenza A and two less-attended viruses, coronavirus OC43 and rhinovirus, were the common etiologic agents in patients hospitalized with AECOPD in Hong Kong. These should be considered in developing diagnostic and intervening strategies pertaining to AECOPD.
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- 2007
208. Fluoroquinolone Resistance in Atypical Pneumococci and Oral Streptococci: Evidence of Horizontal Gene Transfer of Fluoroquinolone Resistance Determinants from Streptococcus pneumoniae
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Fang Chi, Shirley S.L. Chau, Paul K.S. Chan, Julian Tang, and Margaret Ip
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DNA, Bacterial ,Gene Transfer, Horizontal ,Genotype ,medicine.drug_class ,Streptococcus mitis ,Microbial Sensitivity Tests ,medicine.disease_cause ,DNA gyrase ,Microbiology ,chemistry.chemical_compound ,Anti-Infective Agents ,Bacterial Proteins ,Mechanisms of Resistance ,Drug Resistance, Bacterial ,Streptococcus pneumoniae ,medicine ,Humans ,Pharmacology (medical) ,Phylogeny ,Pharmacology ,Genetics ,biology ,Optochin ,Streptococcus ,Streptococcus oralis ,biochemical phenomena, metabolism, and nutrition ,Quinolone ,biology.organism_classification ,Phenotype ,Infectious Diseases ,Amino Acid Substitution ,chemistry ,Viridans streptococci ,Multilocus sequence typing ,Fluoroquinolones - Abstract
Atypical strains, presumed to be pneumococcus, with ciprofloxacin MICs of ≥4.0 μg/ml and unique sequence variations within the quinolone resistance-determining regions (QRDRs) of the gyrase and topoisomerase genes in comparison with the Streptococcus pneumoniae R6 strain, were examined. These strains were reidentified using phenotypic methods, including detection of optochin susceptibility, bile solubility, and agglutination by serotype-specific antisera, and genotypic methods, including detection of pneumolysin and autolysin genes by PCR, 16S rRNA sequencing, and multilocus sequence typing (MLST). The analysis based on concatenated sequences of the six MLST loci distinguished the “atypical” strains from pneumococci, and these strains clustered closely with S. mitis . However, all these strains and five of nine strains from the viridans streptococcal group possessed one to three gyrA , gyrB , parC , and parE genes whose QRDR sequences clustered with those of S. pneumoniae , providing evidence of horizontal transfer of the QRDRs of the gyrase and topoisomerase genes from pneumococci into viridans streptococci. These genes also conferred fluoroquinolone resistance to viridans streptococci. In addition, the fluoroquinolone resistance determinants of 32 well-characterized Streptococcus mitis and Streptococcus oralis strains from bacteremic patients were also compared. These strains have unique amino acid substitutions in GyrA and ParC that were distinguishable from those in fluoroquinolone-resistant pneumococci and the “atypical” isolates. Both recombinational events and de novo mutations play an important role in the development of fluoroquinolone resistance.
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- 2007
209. Prospective comparison of three predictive rules for assessing severity of community-acquired pneumonia in Hong Kong
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Shin Yan Man, Nelson Lee, David S.C. Hui, Gregory E. Antonio, Grace Lui, Joseph J.Y. Sung, Colin A. Graham, Paul K.S. Chan, Shirley S.L. Chau, Anil T. Ahuja, Paulina Mak, Margaret Ip, Mingdong Zhang, and Timothy H. Rainer
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Receiver operating characteristic ,business.industry ,Pneumonia severity index ,Respiratory Infection ,Emergency department ,medicine.disease ,CURB-65 ,Intensive care unit ,law.invention ,Community-acquired pneumonia ,law ,Internal medicine ,Predictive value of tests ,Severity of illness ,Medicine ,business ,Intensive care medicine - Abstract
Background: Community-acquired pneumonia (CAP) is a leading infectious cause of death throughout the world, including Hong Kong. Aim: To compare the ability of three validated prediction rules for CAP to predict mortality in Hong Kong: the 20 variable Pneumonia Severity Index (PSI), the 6-point CURB65 scale adopted by the British Thoracic Society and the simpler CRB65. Methods: A prospective observational study of 1016 consecutive inpatients with CAP (583 men, mean (SD) age 72 (17) years) was performed in a university hospital in the New Territories of Hong Kong in 2004. The patients were classified into three risk groups (low, intermediate and high) according to each rule. The ability of the three rules to predict 30 day mortality was compared. Results: The overall mortality and intensive care unit (ICU) admission rates were 8.6% and 4.0%, respectively. PSI, CURB65 and CRB65 performed similarly, and the areas under the receiver operating characteristic (ROC) curve were 0.736 (95% CI 0.687 to 0.736), 0.733 (95% CI 0.679 to 0.787) and 0.694 (95% CI 0.634 to 0.753), respectively. All three rules had high negative predictive values but relatively low positive predictive values at all cut-off points. Larger proportions of patients were identified as low risk by PSI (47.2%) and CURB65 (43.3%) than by CRB65 (12.6%). Conclusion: All three predictive rules have a similar performance in predicting the severity of CAP, but CURB65 is more suitable than the other two for use in the emergency department because of its simplicity of application and ability to identify low-risk patients.
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- 2007
210. Features discriminating SARS from other severe viral respiratory tract infections
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K. K. Shing, S. S. L. Chau, Anil T. Ahuja, David P. N. Chan, Joseph J.Y. Sung, Paul K.S. Chan, K. T. Wong, David S.C. Hui, Gregory E. Antonio, P. S. K. Mak, Margaret Ip, Nelson Lee, Alex W. H. Ng, Alison P. Galvani, and Timothy H. Rainer
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Male ,myalgia ,Severe Acute Respiratory Syndrome ,Chest pain ,Severity of Illness Index ,Viral Respiratory Tract Infection ,Chlorocebus aethiops ,Child ,skin and connective tissue diseases ,Severe Acute Respiratory Syndrome Patient ,Respiratory Tract Infections ,Aged, 80 and over ,Respiratory tract infections ,Respiratory disease ,General Medicine ,Middle Aged ,Community-Acquired Infections ,Infectious Diseases ,medicine.anatomical_structure ,Severe acute respiratory syndrome-related coronavirus ,Virus Diseases ,Child, Preschool ,Viruses ,Female ,Viral disease ,medicine.symptom ,Adult ,Microbiology (medical) ,medicine.medical_specialty ,Adolescent ,Sensitivity and Specificity ,Article ,Cell Line ,Diagnosis, Differential ,Internal medicine ,medicine ,Animals ,Humans ,Intensive care medicine ,Vero Cells ,Aged ,business.industry ,fungi ,Infant, Newborn ,Infant ,medicine.disease ,Influenza ,body regions ,Pneumonia ,Case-Control Studies ,Respiratory Syncytial Virus ,business ,Respiratory tract - Abstract
This study investigated the discriminatory features of severe acute respiratory syndrome (SARS) and severe non-SARS community-acquired viral respiratory infection (requiring hospitalization) in an emergency department in Hong Kong. In a case-control study, clinical, laboratory and radiological data from 322 patients with laboratory-confirmed SARS from the 2003 SARS outbreak were compared with the data of 253 non-SARS adult patients with confirmed viral respiratory tract infection from 2004 in order to identify discriminatory features. Among the non-SARS patients, 235 (93%) were diagnosed as having influenza infections (primarily H3N2 subtype) and 77 (30%) had radiological evidence of pneumonia. In the early phase of the illness and after adjusting for baseline characteristics, SARS patients were less likely to have lower respiratory symptoms (e.g. sputum production, shortness of breath, chest pain) and more likely to have myalgia (p 99, the sensitivity was 89.1% (95%CI 82.0–94.0) and the specificity was 98.0% (95%CI 95.4–99.3). The area under the receiver operator characteristic curve for predicting SARS when all variables except radiological change were considered was 0.933. Using a cutoff score of >8, the sensitivity was 80.7% (95%CI 72.4–87.3) and the specificity was 94.5% (95%CI 90.9–96.9). Certain clinical manifestations and laboratory changes may help to distinguish SARS from other influenza-like illnesses. Scoring systems may help identify patients who should receive more specific tests for influenza or SARS.
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- 2007
211. Streptococcus suis in Hong Kong
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Ben W.H. Wong, Sau-Lai Lui, Mamie Hui, Shirley S.L. Chau, Edmund S. C. Cheuk, Fang Chi, Margaret Ip, Paul K.S. Chan, Raymond Lai, and Kitty S. C. Fung
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DNA, Bacterial ,Microbiology (medical) ,Serotype ,Meat ,Streptococcus suis ,Swine ,Bacteremia ,Biology ,Polymerase Chain Reaction ,Meningitis, Bacterial ,law.invention ,Microbiology ,law ,RNA, Ribosomal, 16S ,Streptococcal Infections ,medicine ,Animals ,Humans ,Serotyping ,Phylogeny ,Polymerase chain reaction ,Swine Diseases ,Minced pork ,Antiserum ,food and beverages ,General Medicine ,Ribosomal RNA ,medicine.disease ,biology.organism_classification ,Streptococcaceae ,Virology ,Bacterial Typing Techniques ,Electrophoresis, Gel, Pulsed-Field ,Infectious Diseases ,Hong Kong ,Meningitis - Abstract
Streptococcus suis was isolated from 6.1% of raw pork meat from 3 of the 6 wet markets in 6 districts in Hong Kong. S. suis was particularly isolated in sites from the tongue, tonsil, bone, and tail, but not from lean meat/minced pork or internal organs. Isolates were confirmed by polymerase chain reaction using S. suis-specific primers, did not belong to serotype 2 using serotype 2-specific antiserum, and were clustered closely with other known serotypes by phylogenetic analysis. Ten strains from patients admitted to Hong Kong hospitals with sepsis or meningitis in the past 10 years all belonged to type 2, with closely related pulsed-field gel electrophoresis types that were distinct from the S. suis strains isolated from pork in this study. These methods may serve as useful tools in studying and enhancing our understanding of these infections in Hong Kong.
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- 2007
212. Exploring Staphylococcus epidermidis in atopic eczema: friend or foe?
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Yin Ching Tsang, Margaret Ip, T.F. Leung, Nga Hin Pong, and Kam L. Hon
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0301 basic medicine ,Male ,medicine.medical_specialty ,Staphylococcus aureus ,Adolescent ,Antecubital Fossa ,Eczema ,Dermatology ,medicine.disease_cause ,Gastroenterology ,Severity of Illness Index ,Dermatitis, Atopic ,030207 dermatology & venereal diseases ,03 medical and health sciences ,0302 clinical medicine ,Staphylococcus epidermidis ,Internal medicine ,Severity of illness ,medicine ,Humans ,SCORAD ,Child ,Retrospective Studies ,Skin ,Transepidermal water loss ,medicine.diagnostic_test ,biology ,Emollients ,business.industry ,Odds ratio ,Atopic dermatitis ,Staphylococcal Infections ,biology.organism_classification ,medicine.disease ,030104 developmental biology ,Immunology ,Quality of Life ,Female ,business - Abstract
SummaryBackground Staphylococcus aureus (SA) colonization/infection is important in the pathophysiology of childhood atopic dermatitis (AD), but the role of Staphylococcus epidermidis (SE) is unknown. Aim To evaluate if SE co-infects with SA and is associated with more severe disease. Methods Associations between bacteriological culture results of skin swabs (taken from the most severely affected area and at the antecubital fossa) and SCORing Atopic Dermatitis (SCORAD) score, skin hydration, transepidermal water loss (TEWL) and quality of life (QoL) were evaluated. Results In 100 consecutive patients with AD (aged 12.4 ± 4.8 years), SE was present in 28% and 32% of the swabs taken from the most severe area and the flexural area (antecubital fossa), respectively, whereas SA was present in 69% and 55%, respectively. Binomial logistic regression showed that SE was inversely associated with SA growth in the most severely affected skin site [adjusted odds ratio (aOR) = 0.42, 95% CI 0.22–0.81; P = 0.01], frequency of emollient usage (aOR = 0.50, 95% CI 0.29–0.87; P = 0.01) and frequency of oral antihistamine usage (aOR = 0.81, 95% CI 0.65–0.10, P
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- 2015
213. Active surveillance of carbapenem-resistant Enterobacteriaceae in intensive care units: Is it cost-effective in a nonendemic region?
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Wai-tong Ng, Ka-wai Ho, Margaret Ip, and Joyce H. S. You
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0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,Adolescent ,Epidemiology ,Health care provider ,Cost-Benefit Analysis ,030106 microbiology ,Carbapenem-resistant enterobacteriaceae ,beta-Lactam Resistance ,law.invention ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Enterobacteriaceae ,law ,Intensive care ,medicine ,Infection control ,Humans ,030212 general & internal medicine ,Intensive care medicine ,Child ,Sensitivity analyses ,Aged ,Aged, 80 and over ,Cross Infection ,Infection Control ,business.industry ,Health Policy ,Mortality rate ,Analytic model ,Public Health, Environmental and Occupational Health ,Enterobacteriaceae Infections ,Middle Aged ,Intensive care unit ,Survival Analysis ,Intensive Care Units ,Infectious Diseases ,Epidemiological Monitoring ,Hong Kong ,Female ,business - Abstract
Objective Carbapenem-resistant Enterobacteriaceae (CRE) cause significant morbidity and mortality in intensive care unit (ICU) settings. We examined potential cost-effectiveness of active CRE surveillance at ICUs in a nonendemic region from the perspective of a Hong Kong health care provider. Methods A decision analytic model was designed to simulate outcomes of active CRE surveillance in ICUs. Outcome measures included CRE-associated direct medical cost, infection rate, mortality rate, quality-adjusted life year (QALY) loss, and incremental cost per QALY saved by active surveillance. Model inputs were derived from the literature. Sensitivity analyses evaluated the influence of uncertainty of model variables. Results In base-case analysis, the surveillance group was more costly ($1,260 vs $1,256) with lower CRE infection rate (5.670% vs 5.902%), CRE-associated mortality rate (2.139% vs 2.455%), and CRE-associated QALY loss (0.3335 vs 0.3827) than the control group. Incremental cost per QALY saved of active surveillance was $81 per QALY saved. One-way sensitivity analyses found base-case results to be robust to a variety of model inputs. In 10,000 Monte Carlo simulations, the surveillance group was the preferred option 99.98% of time. Conclusions Active CRE surveillance in ICUs appears to be highly cost-effective to reduce CRE infection rate, mortality rate, and QALY loss in a low CRE burden region.
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- 2015
214. Sonodynamic action of hypocrellin B on methicillin-resistant Staphylococcus aureus
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Margaret Ip, Heyu Hua, Pan Wang, Chuanshan Xu, Hongwei Zhang, Albert Wingnang Leung, and Xinna Wang
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0301 basic medicine ,Methicillin-Resistant Staphylococcus aureus ,Radiation-Sensitizing Agents ,Acoustics and Ultrasonics ,Membrane permeability ,DNA damage ,Cell Survival ,Sonication ,Electrochemotherapy ,030106 microbiology ,medicine.disease_cause ,Radiation Dosage ,Microbiology ,03 medical and health sciences ,medicine ,Perylene ,Colony-forming unit ,business.industry ,Quinones ,Sterilization ,Methicillin-resistant Staphylococcus aureus ,Staphylococcus aureus ,Toxicity ,DNA fragmentation ,business - Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes refractory infections and has recently become a serious public health concern. The present study was designed to investigate sonodynamic action of hypocrellin B on MRSA. A MRSA strain (ATCC BAA-43) was used in the present study. The dark toxicity of hypocrellin B on MRSA and its uptake in MRSA first were measured. And then bacteria were incubated with hypocrellin B and exposed to ultrasound. After sonodynamic treatment, colony forming unit assay and bacterial viability assay were conducted. Membrane permeability assay, DNA fragmentation assay, and DNA synthesis assay were also performed to examine the underlying mechanism. The results showed that hypocrellin B at concentrations of up to 500 μM had no toxicity to MRSA in the dark. After incubation for 50 min, hypocrellin B could be maximally absorbed by MRSA, and exhibited significant sonodynamic activity in a dose-dependent manner. The 5-log reduction in colony forming unit (CFU) was observed after hypocrellin B (40 μM) treatment at an intensity of 1.38 W/cm(2) ultrasound for 5 min. Compared to the control, hypocrellin B alone and ultrasound sonication alone group, more dead cells were found and bacterial membrane integrity was notably damaged after sonodynamic treatment of hypocrellin B. However, no remarkable DNA damage was found in MRSA after sonodynamic treatment of hypocrellin B. All the findings demonstrated that hypocrellin B could serve as a potential antibacterial sonosensitizer to significantly cause damage to the membrane integrity of MRSA and inhibit its growth under ultrasound sonication.
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- 2015
215. Draft Genome Sequence of Extensively Drug-Resistant Acinetobacter baumannii Strain CUAB1 from a Patient in Hong Kong, China
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Allen Chi-Shing Yu, Hiuus Hiu-Yu Lau, Jamie Sui-Lam Kwok, Margaret Ip, Alden King-Yung Leung, Ting-Fung Chan, Aldrin Kay-Yuen Yim, and Stephen Kwok-Wing Tsui
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Whole genome sequencing ,Genetics ,biology ,Strain (biology) ,Prokaryotes ,Drug resistance ,biology.organism_classification ,Molecular Biology ,Gene ,Acinetobacter baumannii - Abstract
We report the draft genome sequence of an extensively drug-resistant strain of Acinetobacter baumannii , CUAB1, isolated from a patient in a local Hong Kong hospital. MIC testing was performed, and genes previously associated with drug resistance were located.
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- 2015
216. Draft Genome Sequences of Two Streptococcus pneumoniae Serotype 19F Sequence Type 271 Clinical Isolates with Low- and High-Level Cefotaxime Resistance
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Haokui Zhou, Helen Ma, Stephen Kwok-Wing Tsui, Margaret Ip, and Carmen Li
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Streptococcus pneumoniae serotype ,Cefotaxime ,Strain (chemistry) ,Genetics ,medicine ,Prokaryotes ,Biology ,Molecular Biology ,Virology ,Genome ,Sequence (medicine) ,Microbiology ,medicine.drug - Abstract
We report here the draft genomes of two pneumococcal isolates in Hong Kong, CU_SPNE1_05 and CU_SPNE32_06. Strain CU_SPNE1_05 had a cefotaxime MIC of 1 µg/ml, and CU_SPNE32_06 had an MIC of 32 µg/ml. Both strains belong to the multidrug-resistant serogroup 19, sequence type 271 (clonal complex 3200/271).
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- 2015
217. Genetic Analyses of Penicillin Binding Protein Determinants in Multidrug-Resistant Streptococcus pneumoniae Serogroup 19 CC320/271 Clone with High-Level Resistance to Third-Generation Cephalosporins
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Irene Ang, Margaret Ip, Raymond Lai, Veranja Liyanapathirana, and Helen Ma
- Subjects
Serotype ,Penicillin binding proteins ,Cefotaxime ,Molecular Sequence Data ,Clone (cell biology) ,Taiwan ,Erythromycin ,Microbial Sensitivity Tests ,Biology ,medicine.disease_cause ,beta-Lactam Resistance ,Microbiology ,Epidemiology and Surveillance ,Drug Resistance, Multiple, Bacterial ,Streptococcus pneumoniae ,medicine ,Penicillin-Binding Proteins ,Pharmacology (medical) ,Amino Acid Sequence ,Pharmacology ,Recombination, Genetic ,Virology ,Anti-Bacterial Agents ,Cephalosporins ,Penicillin ,Multiple drug resistance ,Infectious Diseases ,Amino Acid Substitution ,Mutation ,Hong Kong ,medicine.drug - Abstract
We describe the dissemination of a multidrug-resistant (MDR) serogroup 19 pneumococcal clone of representative multilocus sequence type 271 (ST271) with high-level resistance to cefotaxime in Hong Kong and penicillin binding protein ( pbp ) genes and its relationships to Taiwan 19F -14 and the prevalent multidrug-resistant 19A clone (MDR19A-ST320). A total of 472 nonduplicate isolates from 2006 and 2011 were analyzed. Significant increases in the rates of nonsusceptibility to penicillin (PEN) (MIC ≥ 4.0 μg/ml; 9.9 versus 23.3%; P = 0.0005), cefotaxime (CTX) (MIC ≥ 2.0 μg/ml; 12.2 versus 30.3%; P < 0.0001 [meningitis MIC ≥ 1.0 μg/ml; 30.2 versus 48.7%; P = 0.0001]), and erythromycin (ERY) (69.2 versus 84.0%; P = 0.0003) were noted when rates from 2006 and 2011 were compared. The CTX-resistant isolates with MICs of 8 μg/ml in 2011 were of serotype 19F, belonging to ST271. Analyses of the penicillin binding protein 2x (PBP2x) amino acid sequences in relation to the corresponding sequences of the R6 strain revealed M339F, E378A, M400T, and Y595F substitutions found within the ST271 clone but not present in Taiwan 19F -14 or MDR19A. In addition, PBP2bs of ST271 strains and that of the Taiwan 19F -14 clone were characterized by a unique amino acid substitution, E369D, while ST320 possessed the unique amino acid substitution K366N, as does that of MDR19A in the United States. We hypothesize that ST271 originated from the Taiwan 19F -14 lineage, which had disseminated in Hong Kong in the early 2000s, and conferred higher-level β-lactam and cefotaxime resistance through acquisitions of 19 additional amino acid substitutions in PBP2b (amino acid [aa] positions 538 to 641) and altered PBP2x via recombination events. The serogroup 19 MDR CC320/271 clone warrants close monitoring to evaluate its effect after the switch to expanded conjugate vaccines.
- Published
- 2015
218. Differential MicroRNA Expression in Human Macrophages with Mycobacterium tuberculosis Infection of Beijing/W and Non-Beijing/W Strain Types
- Author
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Grace Lui, Eric Leung, Nelson Lee, Ka Fai To, Lin Zheng, Raphael C. Y. Chan, and Margaret Ip
- Subjects
Tuberculosis ,Microarray ,Virulence ,lcsh:Medicine ,Cell Line ,Mycobacterium tuberculosis ,Latent Tuberculosis ,microRNA ,medicine ,Cluster Analysis ,Humans ,RNA, Messenger ,lcsh:Science ,Regulation of gene expression ,Multidisciplinary ,biology ,Gene Expression Profiling ,Macrophages ,lcsh:R ,Reproducibility of Results ,biology.organism_classification ,medicine.disease ,bacterial infections and mycoses ,Gene expression profiling ,MicroRNAs ,Gene Expression Regulation ,Case-Control Studies ,Immunology ,lcsh:Q ,DNA microarray ,Biomarkers ,Research Article ,Signal Transduction - Abstract
Objectives The role of microRNAs in association with Mycobacterium tuberculosis (MTB) infection and the immunology regulated by microRNAs upon MTB infection have not been fully unravelled. We examined the microRNA profiles of THP-1 macrophages upon the MTB infection of Beijing/W and non-Beijing/W clinical strains. We also studied the microRNA profiles of the host macrophages by microarray in a small cohort with active MTB disease, latent infection (LTBI), and from healthy controls. Results The results revealed that 14 microRNAs differentiated infections of Beijing/W from non-Beijing/W strains (P
- Published
- 2015
219. Sonodynamic action of curcumin on foodborne bacteria Bacillus cereus and Escherichia coli
- Author
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Chuanshan Xu, Pan Wang, Albert Wingnang Leung, Zhengrong Yang, Siu-Po Ip, Margaret Ip, Bao-Ting Zhang, and Xinna Wang
- Subjects
DNA, Bacterial ,Curcumin ,Acoustics and Ultrasonics ,Bacillus cereus ,Colony Count, Microbial ,DNA Fragmentation ,medicine.disease_cause ,Microbiology ,chemistry.chemical_compound ,Sonication ,medicine ,Escherichia coli ,Fragmentation (cell biology) ,Hypoxia ,Colony-forming unit ,biology ,Chemistry ,biology.organism_classification ,Anti-Bacterial Agents ,Cereus ,Food Microbiology ,Antibacterial activity ,Bacteria - Abstract
Bacterial contamination is an important cause of foodborne diseases. The present study aimed to investigate sonodynamic action of curcumin on foodborne bacteria Bacillus cereus (B. cereus) and Escherichia coli (E. coli). The uptake of curcumin was measured for optimizing the concentration incubation time before ultrasound sonication, and colony forming units (CFU) were counted after ultrasound treatment. The chromosomal DNA fragmentation of bacteria was analyzed and the effect of hypoxic condition on the antibacterial efficacy of sonodynamic action of curcumin was also assessed in this study. The results showed that the maximum uptake of curcumin in B. cereus and E. coli occurred in 50min after curcumin incubation. Curcumin had sonodynamic bactericidal activity in a curcumin dose-dependent manner, and 5.6-log reduction in CFU of B. cereus was observed after curcumin treatment (2.0μM), however, only 2-log reduction in CFU of E. coli after 40μM curcumin treatment. No significant change in chromosomal DNA was found after the combined treatment of curcumin and ultrasound. The survival of B. cereus and E. coli after sonodynamic treatment in hypoxic group was significantly higher than that in normal oxygen group. These findings indicated that sonodynamic action of curcumin had significant inactivation effect on foodborne bacteria, and B. cereus was more sensitive to sonodynamic treatment of curcumin than E. coli. Sonodynamic antibacterial activity of curcumin might be dependent on the oxygen environment.
- Published
- 2015
220. Use of the housekeeping genes, gdh (zwf) and gki, in multilocus sequence typing to differentiate Streptococcus pneumoniae from Streptococcus mitis and Streptococcus oralis
- Author
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Fang Chi, Margaret Ip, Julian Tang, Shirley S.L. Chau, Mamie Hui, and Paul K.S. Chan
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Microbiology (medical) ,biology ,Streptococcus mitis ,Streptococcus oralis ,General Medicine ,Streptococcaceae ,biology.organism_classification ,medicine.disease_cause ,Bacterial Typing Techniques ,Microbiology ,law.invention ,Housekeeping gene ,Streptococcus pneumoniae ,Infectious Diseases ,Genes, Bacterial ,law ,Genotype ,medicine ,Multilocus sequence typing ,Phylogeny ,Polymerase chain reaction ,Sugar Alcohol Dehydrogenases - Abstract
Polymerase chain reaction and sequencing of the housekeeping genes, gdh (zwf) and gki, based on the primers and alleles from multilocus sequence typing can be used to delineate and support the identity of clinical isolates of Streptococcus pneumoniae and differentiate from the closely related Streptococcus mitis and Streptococcus oralis.
- Published
- 2006
221. Airflows Around Oxygen Masks
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David S.C. Hui, Matthew T. V. Chan, Margaret Ip, Julian W. Tang, Alexandra L.N. Wong, Stephen D. Hall, Paul K.S. Chan, and Joseph J.Y. Sung
- Subjects
Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Infectious Disease Transmission, Patient-to-Professional ,aerosol ,Airflow ,Video Recording ,Oxygen mask ,chemistry.chemical_element ,Severe Acute Respiratory Syndrome ,Critical Care and Intensive Care Medicine ,Models, Biological ,Oxygen ,Article ,Physical Stimulation ,Influenza, Human ,medicine ,Humans ,hospital-acquired ,Respiratory system ,Hypoxia ,Respiratory Tract Infections ,visualization ,Aerosolization ,Aerosols ,Smoke ,Infection Control ,Influenza A Virus, H5N1 Subtype ,business.industry ,transmission ,Masks ,Oxygen Inhalation Therapy ,airborne ,Exhalation ,nosocomial ,infection ,Aerosol ,Surgery ,Severe acute respiratory syndrome-related coronavirus ,chemistry ,Cardiology and Cardiovascular Medicine ,business ,oxygen mask ,airflow ,Biomedical engineering - Abstract
Patients with respiratory infections often require the use of supplemental oxygen via oxygen masks, which, in the hospital, may become sources of aerosolized infectious pathogens. To assess this risk, a human lung model (respiration rate, 12 breaths/min) was designed to test the potential for a simple oxygen mask at a common setting (4 L/min) to disperse potentially infectious exhaled air into the surrounding area. A laser sheet was used to illuminate the exhaled air from the mask, which contained fine tracer smoke particles. An analysis of captured digital images showed that the exhaled air at the peak of simulated exhalation reached a distance of approximately 0.40 m.
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- 2006
222. Rapid Screening of Fluoroquinolone Resistance Determinants in Streptococcus pneumoniae by PCR-Restriction Fragment Length Polymorphism and Single-Strand Conformational Polymorphism
- Author
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Fang Chi, Raymond Lai, Amy Qi, Margaret Ip, and Shirley S.L. Chau
- Subjects
DNA Topoisomerase IV ,DNA, Bacterial ,Microbiology (medical) ,In Vitro Techniques ,Biology ,medicine.disease_cause ,Polymerase Chain Reaction ,DNA gyrase ,law.invention ,law ,Drug Resistance, Bacterial ,Genotype ,Streptococcus pneumoniae ,medicine ,Humans ,Gene ,Polymorphism, Single-Stranded Conformational ,Polymerase chain reaction ,Genetics ,Base Sequence ,Bacteriology ,Single-strand conformation polymorphism ,biochemical phenomena, metabolism, and nutrition ,Amplicon ,Molecular biology ,Amino Acid Substitution ,DNA Gyrase ,Genes, Bacterial ,Restriction fragment length polymorphism ,Polymorphism, Restriction Fragment Length ,Fluoroquinolones - Abstract
A rapid method, using PCR-restriction fragment length and single-strand conformation polymorphism (SSCP), was applied to screen for mutations of the fluoroquinolone resistance determinants in Streptococcus pneumoniae . One hundred nonduplicate Streptococcus pneumoniae isolates with ciprofloxacin MICs of ≥4.0 μg/ml from the Prince of Wales Hospital, Hong Kong, years 2000 to 2003, were examined. For each isolate, PCR amplicons of quinolone resistance-determining regions (QRDRs) of gyrA , gyrB , parC , and parE genes were digested with AluI, HinfI, Sau3AI, and MspI, respectively, and analyzed by SSCP. Each SSCP pattern was given a number, and each isolate obtained a four-digit code, e.g., 1111, that represented the SSCP profile. The SSCP patterns were correlated to mutations characterized from sequence analyses of PCR amplicons. The most common SSCP profile obtained was no. 5232 (40%), which included strains with two amino acid substitutions in the ParC (Lys-137-Asn) and ParE (Ile-460-Val) genes, followed by the SSCP profile 5223 (17%), which included strains with amino acid substitutions in the ParE (Ile-460-Val) gene only. Ten isolates (10%) with amino acid substitutions at GyrA and ParE (±ParC) genes were resistant to levofloxacin with a MIC of ≥16 μg/ml. Other SSCP profiles were unique in distinguishing the common amino acid substitutions in GyrA (Ser-81-Phe) and ParC (Lys-137-Asn, Ser-79-Phe plus Lys-137-Asn, Asp-83-Asn plus Lys-137-Asn, Ser-79-Phe, and Glu-96-Asp). SSCP analysis of restricted fragments generated patterns that were highly discriminative for mutations present in the QRDRs of gyrA , gyrB , parC , and parE . This method provides a database of high resolution profiles on these mutations and allows rapid screening for new mutations of the fluoroquinolone resistance genes.
- Published
- 2006
223. Cryptococcosis in apparently immunocompetent patients
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Clive S. Cockram, E. Lam, Y.K. Tso, Nelson Lee, Grace Lui, Raymond Lai, K.W. Choi, S. Chau, and Margaret Ip
- Subjects
Adult ,Male ,medicine.medical_specialty ,Disease ,Malignancy ,Gastroenterology ,Immunocompromised Host ,Cerebrospinal fluid ,Risk Factors ,Internal medicine ,Humans ,Medicine ,Cryptococcus gattii ,Mycosis ,Aged ,Retrospective Studies ,Cryptococcus neoformans ,biology ,business.industry ,Cryptococcosis ,General Medicine ,Middle Aged ,biology.organism_classification ,medicine.disease ,Cryptococcus ,Immunology ,Hong Kong ,Female ,business ,Immunocompetence ,Meningitis ,Polymorphism, Restriction Fragment Length - Abstract
Summary Background: Few reports have described the clinical and microbiological features of cryptococcosis in immunocompetent patients. Aim: To compare clinical presentations and outcomes of cryptococcosis in immunocompetent vs. immunocompromised patients. Design: Retrospective case series. Methods: All culture- or histology-confirmed cases (n ¼ 46) of cryptococcosis in two acute hospitals in Hong Kong (1995–2005) were included. Clinical presentations, rates of fungaemia, cerebrospinal fluid (CSF) parameters and clinical outcomes were recorded. Results: Twenty patients (43.5%) were apparently immunocompetent, 17 (37.0%) had predisposing factors other than HIV infection, and 9 (19.6%) were HIV-positive. Thirty-one (67.4%) presented with meningitis, four (8.7%) with pulmonary cryptococcosis, and 11 (23.9%) with extraneural, extrapulmonary cryptococcosis. Of the immunocompetent patients with retrievable isolates (n ¼ 8), three (37.5%) were Cryptococcus gattii; all isolates (n ¼ 6) from immunocompromised patients were Cryptococcus neoformans var. grubii. Immunocompetent patients more commonly presented with meningitis (80.0% vs. 47.1%, p ¼ 0.03), and tended toward lower rates of fungaemia (10.0% vs. 35.3%, p ¼ 0.06) and mortality (25.0% vs. 52.9%, p ¼ 0.06). Death was associated with fungaemia (p ¼ 0.01) and underlying malignancy (p < 0.01). In cryptococcal meningitis, immunocompetent patients had longer mean time from illness onset to presentation (34.4 vs. 12.6 days, p ¼ 0.02), more intense inflammatory responses (CSF: white blood cells 108 vs. 35� 10 9 / l, p ¼ 0.03; protein 1.61 g/l vs. 0.79 g/l, p ¼ 0.07), less fungaemia (0% vs. 26.7%, p ¼ 0.04) and more satisfactory clinical outcomes (81.3% vs. 46.7%, p ¼ 0.04). Discussion: A substantial proportion of patients with cryptococcosis are apparently immunocompetent. C. neoformans var. grubii and C. gattii are the common causes. Immunocompetent patients tend to present with localized, indolent neurological disease, with more intense inflammatory responses but better clinical outcomes.
- Published
- 2006
224. Transmission of SARS to healthcare workers. The experience of a Hong Kong ICU
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Patricia Leung, Florence H. Y. Yap, James L. Derrick, Margaret Ip, Charles D. Gomersall, Oi Man Ho, and Gavin M. Joynt
- Subjects
medicine.medical_specialty ,Infectious Disease Transmission, Patient-to-Professional ,Original ,Psychological intervention ,Infection control ,Critical Care and Intensive Care Medicine ,Occupational safety and health ,law.invention ,Cohort Studies ,Hospitals, University ,law ,Anesthesiology ,Intensive care ,Health care ,medicine ,Humans ,Intensive care medicine ,skin and connective tissue diseases ,Disease outbreaks ,Retrospective Studies ,Occupational health ,business.industry ,fungi ,Intensive care unit ,body regions ,Intensive Care Units ,Severe acute respiratory syndrome ,Emergency medicine ,Hong Kong ,business ,Cohort study - Abstract
Objective To describe the extent and temporal pattern of transmission of severe acute respiratory syndrome (SARS) to intensive care unit staff. Design Retrospective observational cohort study. Setting University hospital intensive care unit, caring solely for patients with SARS or suspected to have SARS. Participants Thirty-five doctors and 152 nurses and healthcare assistants who worked in the ICU during the SARS epidemic. Interventions: Infection control measures designed to prevent transmission of disease to staff were implemented. Measurements and results Sixty-seven patients with SARS were admitted to the intensive care unit. Four nurses and one healthcare assistant contracted SARS, with three of these developing symptoms within 10 days of admission of the first patient with SARS. Doctors were exposed to patients with SARS for a median (IQR) of 284 (97–376) h, while nurses and healthcare assistants were exposed for a median (IQR) of 119 (57–166) h. The ICU did not meet international standards for physical space or ventilation. Conclusions In an ICU in which infection control procedures are rigorously applied, the risk to staff of contracting SARS from patients is low, despite long staff exposure times and a sub-standard physical environment. Electronic supplementary material The electronic reference of this article is http://dx.doi.org/10.1007/s00134-006-0081-1 The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.
- Published
- 2006
225. Anti-SARS-CoV IgG response in relation to disease severity of severe acute respiratory syndrome
- Author
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Jenny Ho, Nelson Lee, David S.C. Hui, Catherine W. Ho, Clive S. Cockram, Paul K.S. Chan, Eric Wong, and Margaret Ip
- Subjects
Adult ,Male ,Antibodies, Viral ,Severe Acute Respiratory Syndrome ,Severity of Illness Index ,Article ,Virology ,Severity of illness ,Humans ,Medicine ,Seroconversion ,Respiratory system ,skin and connective tissue diseases ,Disease severity ,Aged ,Retrospective Studies ,SARS ,Aged, 80 and over ,Anti-SARS-CoV IgG ,biology ,business.industry ,fungi ,Respiratory disease ,Retrospective cohort study ,Middle Aged ,medicine.disease ,body regions ,Infectious Diseases ,Severe acute respiratory syndrome-related coronavirus ,Immunoglobulin G ,Immunology ,Cohort ,biology.protein ,Female ,Viral disease ,Antibody ,business - Abstract
Background The association between a robust or depressed antibody response and clinical severity of SARS remains unknown. Objectives To study seroconversion and the magnitude of IgG responses in a SARS cohort with different disease severities. Study design and method A retrospective analysis of all acute and convalescent-phase sera collected from a cohort of laboratory-confirmed SARS cases. Anti-SARS-CoV IgG antibody was detected using indirect immunofluorescence technique and quantified by two-fold serial dilutions. Characteristics of patients who seroconverted “early” (
- Published
- 2006
226. Evaluation of an in-house real-time polymerase chain reaction method to identify group B streptococcus colonization in pregnancy
- Author
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Sik-Wing, Yeung, Pik-Tsz, Cheung, Sze-Lok, Chau, Margaret, Ip, Terence Tzu-Hsi, Lao, Tak-Yeung, Leung, and Wing-Hung, Tam
- Subjects
Adult ,Predictive Value of Tests ,Pregnancy ,Streptococcal Infections ,Humans ,Female ,Pregnant Women ,Pregnancy Complications, Infectious ,Real-Time Polymerase Chain Reaction ,Sensitivity and Specificity ,Streptococcus agalactiae - Abstract
The aim of this study was to evaluate the performance of in-house real-time polymerase chain reaction (qPCR) in detecting group B streptococcus (GBS) colonization compared with the standard culture method in a cohort of pregnant women.A total of 134 rectovaginal swabs were collected from 125 pregnant women, of whom 108 were known carriers or presented with preterm prelabor rupture of membranes. The swabs were placed in Standard Methods Broth (Todd-Hewitt broth supplemented with 6 μg/mL gentamicin and 15 μg/mL nalidixic acid) for culture identification of GBS. An in-house qPCR was also performed from the broth and after overnight incubation of the broth.The detection rate of GBS in this cohort was 30.6% and 50.7% using standard culture method and qPCR, respectively. GBS-specific qPCR assay gave sensitivities of 97.6% and 100%, specificities of 73.1% and 71.0%, and negative predictive values of 98.6% and 100% from direct specimen and from broth after overnight incubation, respectively.The in-house qPCR test has high sensitivity in detecting GBS colonization. The high negative predictive value helps to avoid unnecessary use of antibiotics in uncolonized women.
- Published
- 2014
227. Draft Genome Sequence of Clostridium butyricum Strain NOR 33234, Isolated from an Elderly Patient with Diarrhea
- Author
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Jamie S. L. Kwok, Wai-Yip Lam, Ting-Fung Chan, Margaret Ip, and Stephen Kwok-Wing Tsui
- Subjects
Whole genome sequencing ,biology ,Strain (biology) ,Clostridium difficile ,biology.organism_classification ,Genome ,Microbiology ,Diarrhea ,Genetics ,medicine ,Prokaryotes ,medicine.symptom ,Elderly patient ,Molecular Biology ,Clostridium clostridioforme ,Clostridium butyricum - Abstract
Clostridium butyricum is one of the species frequently present in patients' stool samples. However, the identification of this species is sometimes difficult. Here, we present the draft genome of Clostridium butyricum NOR 33234, which was isolated from a patient with suspected Clostridium difficile infection-associated diarrhea and resembles Clostridium clostridioforme in biochemical tests.
- Published
- 2014
228. Contemporary Methicillin-Resistant Staphylococcus aureus Clones in Hong Kong
- Author
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Wei-Kwang Luk, Cindy W. S. Tse, Raymond W. H. Yung, D. J. Lyon, Margaret Ip, Mark C. Enright, Tak-Keung Ng, and Philip Hung
- Subjects
DNA, Bacterial ,Microbiology (medical) ,Staphylococcus aureus ,Epidemiology ,Erythromycin ,Bacteremia ,Microbial Sensitivity Tests ,Biology ,medicine.disease_cause ,Staphylococcal infections ,Microbiology ,SmaI ,Hospitals, Urban ,Bacterial Proteins ,medicine ,Pulsed-field gel electrophoresis ,Humans ,Deoxyribonucleases, Type II Site-Specific ,SCCmec ,Staphylococcal Infections ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,medicine.disease ,Methicillin-resistant Staphylococcus aureus ,Virology ,Anti-Bacterial Agents ,Bacterial Typing Techniques ,Electrophoresis, Gel, Pulsed-Field ,Hong Kong ,Multilocus sequence typing ,Methicillin Resistance ,medicine.drug - Abstract
Two hundred nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) isolates causing bacteremia in patients in four major Hong Kong hospitals during the period 2000 to 2001 were characterized by antibiogram, pulsed-field gel electrophoresis (PFGE) using SmaI restriction enzymes, and determination of staphylococcal cassette chromosome mec (SCC mec ) types. Nine PFGE types, A to I, were obtained. PFGE type A constituted 50% (99/200) of all isolates and was present in isolates from all four hospitals. PFGE types A to E, had previously been identified as the major types at one of the hospitals from 1988 to 2000. The majority had a resistance profile to tetracycline (T), erythromycin (E), clindamycin (D), gentamicin (G), tobramycin (To), and ciprofloxacin (Ci), and belonged to SCC mec type III; and representatives belonged to clonal complex 239 (CC239) (MRSA with SCC mec type III and sequence type 239, designated ST239-MRSA-III). PFGE types F to I were new patterns that had not been previously identified in isolates from Hong Kong. PFGE type F constituted 18% (35/200) of MRSAs, had resistance profile TEGToCi, and belonged to CC5 (ST5-MRSA-II). PFGE type G included 13% (26/200) of MRSAs, had resistance profile TECi, and belonged to CC45 with SCC mec type I or II. PFGE type H had characteristics similar to those of CC239, while PFGE type I included three isolates, two of which expressed resistance to oxacillin and fusidic acid only. Two of these strains had SCC mec IVa and carried sequence type 389, with a multilocus sequence typing allelic profile of 3-35-19-2-20-26-39. Contemporary MRSAs causing bacteremia in Hong Kong hospitals belong to three clonal complexes (CC5, CC45, and CC239). The most prevalent MRSA clone in Hong Kong belongs to CC239, with PFGE types A to E and H, SCC mec type III, ST239, and a resistance profile of TEDGToCi.
- Published
- 2005
229. An International Prospective Study of Pneumococcal Bacteremia: Correlation with In Vitro Resistance, Antibiotics Administered, and Clinical Outcome
- Author
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Charles Feldman, Margaret Ip, Larry M. Baddour, Victor L. Yu, Jordi Rello, Arthur J. Morris, Åke Örtqvist, M. Bernadete F. Chedid, Christine C. Chiou, Carlos M. Luna, Wen Chien Ko, David R. Snydman, Antoine Andremont, and Keith P. Klugman
- Subjects
Adult ,Microbiology (medical) ,medicine.medical_specialty ,Cefotaxime ,Adolescent ,medicine.drug_class ,Penicillin Resistance ,Statistics as Topic ,Antibiotics ,Bacteremia ,Microbial Sensitivity Tests ,Penicillins ,medicine.disease_cause ,Pneumococcal Infections ,Risk Factors ,Internal medicine ,Drug Resistance, Bacterial ,Streptococcus pneumoniae ,medicine ,Humans ,Prospective Studies ,Aged ,Aged, 80 and over ,business.industry ,Middle Aged ,medicine.disease ,Anti-Bacterial Agents ,Penicillin ,Pneumococcal infections ,Treatment Outcome ,Infectious Diseases ,Immunology ,Ceftriaxone ,business ,Cefuroxime ,medicine.drug - Abstract
We performed a prospective, international, observational study of 844 hospitalized patients with blood cultures positive for Streptococcus pneumoniae. Fifteen percent of isolates had in vitro intermediate susceptibility to penicillin (minimum inhibitory concentration [MIC], 0.12-1 microg/mL), and 9.6% of isolates were resistant (MIC, >or=2 microg/mL). Age, severity of illness, and underlying disease with immunosuppression were significantly associated with mortality; penicillin resistance was not a risk factor for mortality. The impact of concordant antibiotic therapy (i.e., receipt of a single antibiotic with in vitro activity against S. pneumoniae) versus discordant therapy (inactive in vitro) on mortality was assessed at 14 days. Discordant therapy with penicillins, cefotaxime, and ceftriaxone (but not cefuroxime) did not result in a higher mortality rate. Similarly, time required for defervescence and frequency of suppurative complications were not associated with concordance of beta-lactam antibiotic therapy. beta-Lactam antibiotics should still be useful for treatment of pneumococcal infections that do not involve cerebrospinal fluid, regardless of in vitro susceptibility, as determined by current NCCLS breakpoints.
- Published
- 2003
230. Frequent Conversion of Tuberculosis Screening Test During Anti-Tumour Necrosis Factor Therapy in Chinese Patients with Inflammatory Bowel Disease: A Prospective Study with 3 Years Follow-Up
- Author
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Francis K.L. Chan, Siew C. Ng, Grace Lui, Margaret Ip, Esther H. Y. Hung, Joseph J.Y. Sung, Kitty K.T. Cheung, Nelson Lee, Whitney Tang, Amy Li, Justin C.Y. Wu, and Lai-Shan Tam
- Subjects
medicine.medical_specialty ,Hepatology ,business.industry ,Anti tumour necrosis factor ,Gastroenterology ,Tuberculosis screening ,medicine.disease ,Inflammatory bowel disease ,Surgery ,Internal medicine ,medicine ,Prospective cohort study ,business - Published
- 2017
231. Performance of interferon-gamma release assay for tuberculosis screening in inflammatory bowel disease patients
- Author
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Whitney Tang, Zheng Lin, Grace Lui, Nelson Lee, Carmen Kee, Siew C. Ng, Francis K.L. Chan, Margaret Ip, Sunny H. Wong, Justin C.Y. Wu, Esther H. Y. Hung, and Joseph J.Y. Sung
- Subjects
Adult ,Male ,medicine.medical_specialty ,Tuberculosis ,Interferon gamma release assay ,Azathioprine ,Inflammatory bowel disease ,Antiviral Agents ,Interferon-gamma ,Crohn Disease ,Latent Tuberculosis ,Internal medicine ,medicine ,Immunology and Allergy ,Humans ,Mass Screening ,Prospective Studies ,Prospective cohort study ,Mass screening ,Latent tuberculosis ,business.industry ,Tuberculin Test ,Gastroenterology ,Case-control study ,Middle Aged ,medicine.disease ,Prognosis ,Case-Control Studies ,Colitis, Ulcerative ,Female ,business ,Interferon-gamma Release Tests ,medicine.drug ,Follow-Up Studies - Abstract
Background Screening for latent tuberculosis (TB) is mandatory in inflammatory bowel disease (IBD) before starting anti-tumor necrosis factor therapy. Data on the utility of screening tests in populations with moderate background risk of TB are limited. This study aims to evaluate the performance of interferon-gamma release assay (IGRA) with QuantiFERON-TB Gold in IBD patients in a TB endemic region. Methods Two hundred sixty-eight consecutive adult IBD patients and 234 healthy controls were prospectively recruited. Detailed clinical history, chest x-ray findings, and IGRA results were documented for all individuals. The IGRA positive rates between IBD patients, with or without immunosuppressant, and healthy controls were compared. Results The IGRA result was positive in 21.9% of IBD patients and 19.2% of healthy controls (P = 0.535). IBD patients on immunosuppressive therapy had a significantly lower IGRA positive rate (13.0% versus 29.6%; P = 0.002) compared with immunosuppressant-naive IBD patients. This difference seemed to be most prominent for patients taking azathioprine (11.8% versus 27.3%, P = 0.006). Conclusions IGRA results are negatively impacted by immunosuppressive therapy. Current guidelines suggesting TB screening before anti-tumor necrosis factor therapy may be inadequate in patients already on immunosuppressive drugs. Latent TB testing seems best performed before the initiation of immunosuppressive therapies in IBD patients.
- Published
- 2014
232. Draft Genome Sequence of Methicillin-Resistant Staphylococcus aureus CUHK_188 (ST188), a Health Care-Associated Bacteremic Isolate from Hong Kong
- Author
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Stephen Kwok-Wing Tsui, Margaret Ip, Zheng Wang, Wai Yip Lam, and Haokui Zhou
- Subjects
Whole genome sequencing ,0303 health sciences ,030306 microbiology ,Biology ,medicine.disease_cause ,Health care associated ,Methicillin-resistant Staphylococcus aureus ,3. Good health ,Microbiology ,03 medical and health sciences ,Staphylococcus aureus ,Genetics ,medicine ,Prokaryotes ,University teaching ,Spa typing ,Molecular Biology ,030304 developmental biology ,Sequence (medicine) - Abstract
We report the draft genome sequence of a methicillin-resistant Staphylococcus aureus strain designated CUHK_188, isolated from a bacteremic patient undergoing treatment at a university teaching hospital in Hong Kong. This strain belongs to sequence type 188 (ST188), with spa type t189 and staphylococcal cassette chromosome mec type V.
- Published
- 2014
233. Cost-Effectiveness of Active Surveillance of Beta-D-Glucan in Intensive Care Units in Hong Kong
- Author
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Margaret Ip, Joyce H. S. You, and Y.-k. Pang
- Subjects
medicine.medical_specialty ,Cost effectiveness ,business.industry ,Health Policy ,Intensive care ,Emergency medicine ,Public Health, Environmental and Occupational Health ,Medicine ,Beta d glucan ,business - Published
- 2016
234. Humoral response to conjugate pneumococcal vaccine in paediatric oncology patients
- Author
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Patrick Man Pan Yuen, Ming Kong Shing, Vincent Lee, Yvonne Chu, Frankie W.T. Cheng, Margaret Ip, Wing Kwan Leung, Chi Kong Li, and Zheng Lin
- Subjects
Male ,Serotype ,medicine.medical_specialty ,Heptavalent Pneumococcal Conjugate Vaccine ,Adolescent ,Opportunistic Infections ,complex mixtures ,Pneumococcal Infections ,Pneumococcal conjugate vaccine ,Pneumococcal Vaccines ,Neoplasms ,Internal medicine ,medicine ,Humans ,Child ,Vaccines, Conjugate ,biology ,Paediatric oncology ,business.industry ,Infant ,Antibodies, Bacterial ,Streptococcus pneumoniae ,Antibody response ,Pneumococcal vaccine ,Child, Preschool ,Hematologic Neoplasms ,Immunoglobulin G ,Pediatrics, Perinatology and Child Health ,Cohort ,Immunology ,biology.protein ,Female ,Antibody ,business ,medicine.drug - Abstract
Objective Pneumococcal conjugate vaccine (PCV) is an effective way to prevent invasive pneumococcal diseases in high risk populations. The efficacy of this vaccine in paediatric oncology patients remains unknown. Design and setting The authors evaluated the antibody response to seven pneumococcal serotypes in paediatric oncology patients given two doses of heptavalent PCV (PCV-7). Results Forty-four patients (20 males; 24 females) with median age 9.5 years were studied. After two doses of PCV-7, 86–100% of patients had protective antibody titres against the seven vaccine serotypes. Increases in geometric mean antibody concentrations ranged from 3.8-fold for serotype 19F to 85.8-fold for serotype 14. There was no documented invasive pneumococcal disease in our cohort during the study period. Conclusion PCV can elicit protective antipneumococcal antibody responses in paediatric oncology patients.
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- 2010
235. Application of a target enrichment-based next-generation sequencing protocol for identification and sequence-based prediction of pneumococcal serotypes
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Veranja Liyanapathirana, Tak Keung Ng, Kitty S. C. Fung, Margaret Ip, Haokui Zhou, Irene Ang, and Dominic N.C. Tsang
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Microbiology (medical) ,Serotype ,Whole genome sequencing ,Genotype ,High-Throughput Nucleotide Sequencing ,Computational biology ,Biology ,Polysaccharide Vaccine ,medicine.disease_cause ,Microbiology ,DNA sequencing ,Streptococcus pneumoniae ,Next generation sequencing (NGS) ,Parasitology ,medicine ,Humans ,Identification (biology) ,Serotyping ,Research Article - Abstract
Background The use of whole-genome sequencing in microbiology at a diagnostic level, although feasible, is still limited by the expenses associated and by the complex bioinformatics pipelines in data analyses. We describe the use of target enrichment-based next-generation sequencing for pneumococcal identification and serotyping as applied to the polysaccharide 23 valent vaccine serotypes as an affordable alternative to whole genome sequencing. Results Correct identification of Streptococcus pneumoniae and prediction of common vaccine serotypes: 12 to serotype level and the rest to serogroup levels were achieved for all serotypes with >500 reads mapped against serotypes sequences. A proportion-based criterion also enabled the identification of two serotypes present in the same sample, thus indicating the possibility of using this method in detecting co-colonizing serotypes. The results obtained were comparable to or an improvement on the currently existing molecular serotyping methods for S. pneumoniae in relation to the polysaccharide vaccine serotypes. Conclusion We propose that this method has the potential to become an affordable and adaptable alternative to whole-genome sequencing for pneumococcal identification and serotyping.
- Published
- 2013
236. Rapid identification of medically important Candida to species level by polymerase chain reaction and single-strand conformational polymorphism
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Miu Ling Chin, Margaret Ip, Augustine F. B. Cheng, Paul K.S. Chan, and Mamie Hui
- Subjects
Microbiology (medical) ,Time Factors ,Polymerase Chain Reaction ,Microbiology ,law.invention ,law ,Amphotericin B ,Candida albicans ,RNA, Ribosomal, 28S ,Genotype ,medicine ,Humans ,Polymorphism, Single-Stranded Conformational ,Polymerase chain reaction ,Candida ,Genetics ,biology ,Candidiasis ,RNA, Fungal ,Single-strand conformation polymorphism ,General Medicine ,Fungi imperfecti ,Amplicon ,biology.organism_classification ,Infectious Diseases ,Fluconazole ,medicine.drug - Abstract
Invasive fungal disease has taken a great toll on immunocompromised patients. With the emergence of fluconazole and amphotericin B resistance, the rapid identification of fungi to species level is of clinical relevance in guiding appropriate antifungal therapy. Among these opportunistic fungi, Candida species are the most commonly encountered. We had developed a molecular method utilizing single-strand conformational polymorphism (SSCP) to delineate different patterns on a 260-bp amplicon from the 28S rRNA gene from six medically important Candida species. The SSCP banding patterns obtained from a total of 52 isolates were sufficiently unique to allow distinction between the species, thus indicated a high level of specificity. This method of PCR-SSCP can provide a simple and specific method for the rapid identification of medically important Candida to species level.
- Published
- 2000
237. Presence of human herpesviruses 6, 7, and 8 DNA sequences in normal brain tissue
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Paul K.S. Chan, Mamie Hui, Ho Keung Ng, Augustine F. B. Cheng, Margaret Ip, and Jo L.K. Cheung
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biology ,viruses ,Neurotropism ,virus diseases ,medicine.disease_cause ,biology.organism_classification ,Virology ,Virus ,DNA sequencing ,Herpesviridae ,chemistry.chemical_compound ,Infectious Diseases ,chemistry ,Immunology ,medicine ,Gammaherpesvirinae ,Viral disease ,Nested polymerase chain reaction ,DNA - Abstract
The three novel human herpesviruses (HHV) 6, 7, and 8 are predominantly, but not exclusively, lymphotropic. In an attempt to elucidate their neurotropism in vivo, viral DNA sequences present in fresh autopsy cortical brain tissues obtained from 84 consecutive Chinese subjects (mean age, 66.9 years; range, 21-98 years) were detected by a nested polymerase chain reaction. These patients were apparently immunocompetent and free of clinical signs of viral diseases. HHV-6 DNA was detected in 36 of 84 (42.9%) patients, and the DNA-positive and -negative groups did not show a significant difference in age or sex distribution. Of the 36 HHV-6 DNA-positive cases, 9 (25%) were variant A and 27 (75%) were variant B. In view of the lower prevalence of variant A than variant B in the adult population, the two variants may share a comparable neuroinvasive potential. HHV-7 and HHV-8 DNA were detected respectively in three and two patients. The low positive rates of HHV-7 and HHV-8 may represent a relatively lower neuroinvasive potential of the viruses. Alternatively, the localization of HHV-7 and HHV-8 may be more restricted and the sampled cortical tissues may not represent the most abundant site of persistence in the nervous system. The results provide molecular evidence of the presence of the three newly identified herpesviruses in brain tissue. The pathogenic role for HHV-7 and HHV-8, as with HHV-6, in neurological diseases should not be overlooked.
- Published
- 1999
238. Evidence of Clonal Dissemination of Multidrug-Resistant Streptococcus pneumoniae in Hong Kong
- Author
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Raymond W. H. Yung, Margaret Ip, Augustine F. B. Cheng, Colin Chan, and D. J. Lyon
- Subjects
Microbiology (medical) ,Serotype ,clone (Java method) ,Muramoylpentapeptide Carboxypeptidase ,Biology ,medicine.disease_cause ,Microbiology ,Bacterial Proteins ,Streptococcus pneumoniae ,Genotype ,medicine ,Pulsed-field gel electrophoresis ,Penicillin-Binding Proteins ,Bacterial Capsules ,Antibacterial agent ,Molecular epidemiology ,Drug Resistance, Microbial ,Bacteriology ,DNA Fingerprinting ,Drug Resistance, Multiple ,Electrophoresis, Gel, Pulsed-Field ,Hexosyltransferases ,DNA profiling ,Peptidyl Transferases ,Carrier Proteins - Abstract
The relationship between the phenotypic and genotypic characteristics of 105 penicillin-intermediate or -resistant Streptococcus pneumoniae isolates saved during 1994 to 1997 at the Prince of Wales Hospital and Pamela Youde Nethersole Eastern Hospital, Hong Kong, was studied. The pbp genes for penicillin-binding proteins 1a, 2b, and 2x for each isolate were amplified by PCR, and the products were digested with restriction enzymes Hin fI and Alu I. A combination of the pulsed-field gel electrophoresis (PFGE) profiles, pbp fingerprints, and phenotypic characteristics of capsular types and antibiograms enabled these isolates to be divided into four major groups. Seventy-four percent (78 of 105) of the strains, belonging to serotypes 23F, 19F, and 14, showed indistinguishable pbp fingerprint patterns (group A1, 1-1-1, 1-1-1), with PFGE patterns belonging to group A and its subtypes, suggesting that these strains were closely related. Eighty-three percent (65 of 78) of these isolates were also resistant to tetracycline, erythromycin, chloramphenicol, and trimethoprim. The type 23F isolates were indistinguishable from representative strains of the Spanish 23F clone by these molecular methods, indicating that these strains may be variants of the Spanish 23F clone. Serotype 6B accounted for 19% (20 of 105) of the isolates with reduced penicillin susceptibility and was made up of variants belonging to four different pbp fingerprint groups with the PFGE pattern group B, the predominant group being indistinguishable from that of the Spanish 6B clone. Other PFGE and fingerprint groups were mainly obtained from penicillin-susceptible strains of various serotypes. The results suggest that the rapid emergence of drug-resistant S. pneumoniae in Hong Kong has been due to the rapid dissemination of several successful clones.
- Published
- 1999
239. Are β-lactams related to higher morbidity and mortality in urinary tract infections caused by extended-spectrum β-lactamase-producing Escherichia coli?
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K.Y. Wong, H.W. Kei, Margaret Ip, Joyce H. S. You, Nelson Lee, T. Marasinghe, and W.C. Lau
- Subjects
Microbiology (medical) ,business.industry ,Urinary system ,General Medicine ,beta-Lactams ,medicine.disease_cause ,beta-Lactam Resistance ,beta-Lactamases ,Anti-Bacterial Agents ,Microbiology ,Treatment Outcome ,Infectious Diseases ,Carbapenems ,Urinary Tract Infections ,β lactams ,Escherichia coli ,Hong Kong ,Humans ,Medicine ,business ,Escherichia coli Infections ,Retrospective Studies - Published
- 2008
240. Swine methicillin-resistant Staphylococcus aureus carrying toxic-shock syndrome toxin gene in Hong Kong, China.
- Author
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Sapugahawatte, Dulmini Nanayakkara, Carmen Li, Yun Kit Yeoh, Dharmaratne, Priyanga, Chendi Zhu, and Margaret Ip
- Published
- 2020
- Full Text
- View/download PDF
241. Identification of a Streptococcus agalactiae Serotype III Subtype 4 Clone in Association with Adult Invasive Disease in Hong Kong
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Fanrong Kong, Michelle H. Y. Tsui, Gwendolyn L. Gilbert, Edmund S. C. Cheuk, Margaret Ip, and Tse Ngong Leung
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Microbiology (medical) ,Gel electrophoresis ,Serotype ,biology ,Invasive disease ,Clone (cell biology) ,Bacteriology ,biology.organism_classification ,Streptococcaceae ,medicine.disease_cause ,Virology ,Electrophoresis, Gel, Pulsed-Field ,Streptococcus agalactiae ,Microbiology ,Streptococcus agalactiae serotype III ,Streptococcal Infections ,DNA Transposable Elements ,medicine ,Serotyping ,Bacteria - Abstract
Characterization of Streptococcus agalactiae serotype III isolates revealed a subtype 4 clone that has an indistinguishable pulsed-field gel electrophoresis pattern and possesses a C-α protein, IS 1381 , and a novel sequence type (ST), ST 283, by multilocus sequence tagging. This clone was significantly associated with diseases caused by invasive strains from nonpregnant adults ( P ≤ 0.01, chi-square test) and was not present in the genital tracts of pregnant mothers.
- Published
- 2006
242. Biases in human papillomavirus genotype prevalence assessment associatedwith commonly used consensus primers
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Jo L.K. Cheung, Mamie Hui, Tak Hong Cheung, Ann O. Y. Tam, Margaret Ip, May M.Y. Yu, Keith W.K. Lo, Ka Fai To, Paul K.S. Chan, So Fan Yim, Yick Fu Wong, and Denise P. C. Chan
- Subjects
Cancer Research ,medicine.medical_specialty ,Genotype ,Uterine Cervical Neoplasms ,Cancer Vaccines ,Sensitivity and Specificity ,Virus ,law.invention ,law ,Epidemiology ,Prevalence ,medicine ,Humans ,Papillomaviridae ,Polymerase chain reaction ,DNA Primers ,Cervical cancer ,business.industry ,Papillomavirus Infections ,Reproducibility of Results ,Consensus primer ,medicine.disease ,Virology ,Oncology ,Carcinoma, Squamous Cell ,Female ,Viral disease ,Primer (molecular biology) ,business - Abstract
Consensus primers targeting human papillomaviruses (HPVs) have biases in sensitivity toward certain HPV types. We applied 3 primer sets (GP5+/6+, MY09/11, PGMY09/11) in parallel on 120 Chinese cervical cancer specimens. GP5+/6+ exhibited a poor sensitivity for HPV52, for which the prevalence among squamous cell cervical cancer was underestimated from 14.6% to 0%. The fact that HPV52 should rank second in prevalence among squamous cell cervical carcinoma in Hong Kong could be missed if GP5+/6+, a worldwide commonly used primer set, was selected for HPV detection. Biases in HPV type-specific sensitivity may result in misprioritization of vaccine candidates.
- Published
- 2005
243. Prevention of gram-positive infections in peritoneal dialysis patients in Hong Kong: a cost-effectiveness analysis
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Joyce H. S. You, Carlos Wong, Margaret Ip, and In-wa Luk
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medicine.medical_specialty ,Epidemiology ,medicine.medical_treatment ,Administration, Topical ,Cost-Benefit Analysis ,Peritonitis ,Mupirocin ,Peritoneal dialysis ,chemistry.chemical_compound ,Internal medicine ,Medicine ,Humans ,In patient ,Intensive care medicine ,Gram-Positive Bacterial Infections ,Infection Control ,business.industry ,Health Policy ,Mortality rate ,Public Health, Environmental and Occupational Health ,Cost-effectiveness analysis ,Health Care Costs ,medicine.disease ,Survival Analysis ,Quality-adjusted life year ,Anti-Bacterial Agents ,Infectious Diseases ,chemistry ,Quality of Life ,Hong Kong ,lipids (amino acids, peptides, and proteins) ,business ,Lower mortality ,Peritoneal Dialysis - Abstract
Background Gram-positive bacteria are the major causative pathogens of peritonitis and exit site infection in patients undergoing peritoneal dialysis (PD). We investigated the cost-effectiveness of regular application of mupirocin at the exit site in PD recipients from the perspective of health care providers in Hong Kong. Methods A decision tree was designed to simulate outcomes of incident PD patients with and without regular application of mupirocin over a 1-year period. Outcome measures included total direct medical costs, quality-adjusted life-years (QALYs) gained, and gram-positive infection–related mortality rate. Model inputs were derived from the literature. Sensitivity analyses evaluated the impact of uncertainty in all model variables. Results In a base case analysis, the mupirocin group had a higher expected QALY value (0.6496 vs 0.6456), a lower infection-related mortality rate (0.18% vs 1.64%), and a lower total cost per patient (US $258 vs $1661) compared with the control group. The rate of gram-positive peritonitis without mupirocin and the risk of gram-positive peritonitis with mupirocin were influential factors. In 10,000 Monte Carlo simulations, the mupirocin group had significantly lower associated costs, higher QALYs, and a lower mortality rate 99.9% of the time. Conclusions Topical mupirocin appears to be a cost-effective preventive measure against gram-positive infection in incident patients undergoing PD. The cost-effectiveness of mupirocin is affected by the level of infection risk reduction and subject to resistance against mupirocin.
- Published
- 2013
244. Molecular and Clinical Characteristics of Clonal Complex 59 Methicillin-Resistant Staphylococcus aureus Infections in Mainland China
- Author
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X. Shen, Margaret Ip, Chuanqing Wang, Yonghong Yang, Sangjie Yu, Zhou Fu, Yuejie Zheng, Changan Zhao, Mingjiao Sun, Kaihu Yao, Yunxiao Shang, Juan Li, Changcong Li, Li Deng, Guoying Huang, Lijuan Wang, and Jing Sun
- Subjects
Health Screening ,Epidemiology ,lcsh:Medicine ,Pathogenesis ,medicine.disease_cause ,Pediatrics ,Pathology ,Prevalence ,Prospective Studies ,lcsh:Science ,Child ,Staphylococci ,Multidisciplinary ,Virulence ,Reverse Transcriptase Polymerase Chain Reaction ,Microbial Mutation ,Child Health ,Drug Resistance, Microbial ,Staphylococcal Infections ,Bacterial Pathogens ,Electrophoresis, Gel, Pulsed-Field ,Staphylococcus aureus ,Medical Microbiology ,Medicine ,Infectious diseases ,Public Health ,Molecular Pathology ,Research Article ,Plasmids ,DNA, Bacterial ,Methicillin-Resistant Staphylococcus aureus ,Pediatric Critical Care ,China ,Virulence Factors ,Bacterial diseases ,Microbial Sensitivity Tests ,Biology ,Staphylococcal infections ,Microbiology ,Species Specificity ,Diagnostic Medicine ,Pulsed-field gel electrophoresis ,medicine ,Humans ,Typing ,SCCmec ,lcsh:R ,Bacteriology ,Gene Expression Regulation, Bacterial ,medicine.disease ,Methicillin-resistant Staphylococcus aureus ,Virology ,Genes, Bacterial ,Multilocus sequence typing ,lcsh:Q ,General Pathology ,Multilocus Sequence Typing - Abstract
Detailed molecular analyses of Clonal Complex 59 (CC59) methicillin-resistant Staphylococcus aureus (MRSA) isolates from children in seven major cities across Mainland China were examined. A total of 110 CC59 isolates from invasive and non-invasive diseases were analyzed by multilocus sequence typing (MLST), Staphylococcus cassette chromosome mec (SCCmec) typing, staphylococcal protein A (spa) typing and pulsed-field gel electrophoresis (PFGE). Antibiotics susceptibilities, carriage of plasmids and 42 virulence genes and the expression of virulence factors were examined. ST59 (101/110, 91.8%) was the predominant sequence type (ST), while single locus variants (SLVs) belonging to ST338 (8/110, 7.3%) and ST375 (1/110, 0.9%) were obtained. Three SCCmec types were found, namely type III (2.7%), type IV (74.5%) and type V (22.7%). Seven spa types including t437, which accounted for 87.3%, were determined. Thirteen PFGE types were obtained. PFGE types A and B were the major types totally accounting for 81.8%. The dominant clone was ST59-t437-IVa (65.5%), followed by ST59-t437-V (14.5%). The positive rate of luks-PV and lukF-PV PVL encoding (pvl) gene was 55.5%. Plasmids were detected in 83.6% (92/110) of the strains. The plasmid size ranging from 23.4 kb to 50 kb was most prevalent which accounted for 83.7% (77/92). A significantly lower expression of hla was found in ST59-t437-IVa compared with ST59-t437-V. Among the 110 cases, 61.8% of the patients were less than 1 year old. A total of 90 cases (81.8%) were community-associated (CA) infections whereas 20 cases (18.2%) were hospital-associated (HA) infections. Out of the 110 patients, 36.4% (40/110) were diagnosed with invasive infectious diseases in which ST59-t437-IVa accounted for 67.5% (27/40). In brief, ST59-t437-IVa was proved as the dominant clone in CC59 MRSA strains. The carriage rate of pvl gene was high. CC59 MRSA could result in CA and HA infections. The majortiy of MRSA infection children were in young age.
- Published
- 2013
245. Cardiopulmonary morbidity of streptococcal infections in a PICU
- Author
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Kam-Lun E, Hon, Antony, Fu, Ting Fan, Leung, Terence C W, Poon, Wai Hung, Cheung, Chor Yiu, Fong, Yee Ting Christina, Ho, Tsui Yin Jamie, Lee, Tam Man, Ng, Wai Ling, Yu, Kam Lau, Cheung, Vivian, Lee, and Margaret, Ip
- Subjects
Lung Diseases ,Male ,Critical Care ,Infant ,Microbial Sensitivity Tests ,Length of Stay ,Intensive Care Units, Pediatric ,Anti-Bacterial Agents ,Cardiovascular Diseases ,Child, Preschool ,Streptococcal Infections ,Humans ,Female ,Child ,Retrospective Studies - Abstract
The streptococci are important bacteria that cause serious childhood infections. We investigated cardiopulmonary morbidity associated with streptococcal infection and pediatric intensive care unit (PICU) admission.A retrospective study between 2002 and 2013 of all children with a laboratory isolation of streptococcus.There were 40 (2.3%) PICU patients with streptococcal isolations including Streptococcus pyogenes (Group A streptococcus, GAS, n = 7), Streptococcus agalactiae (Group B streptococcus, GBS, n = 5), Streptococcus pneumoniae (SP, n = 20), alpha-hemolytic (n = 4), beta-hemolytic (n = 2) and gama-hemolytic (n = 2) streptococci. Comparing among GAS, GBS and SP, respiratory isolates were more likely positive for GAS or SP (P = 0.033), whereas cerebrospinal fluid was more likely positive for GBS (P = 0.002). All GAS and GBS, and the majority of SP (90%) were sensitive to penicillin. All SP specimens were sensitive to cefotaxime and vancomycin. These infections were associated with high PICU mortality of 43%, 20% and 25%, respectively. Isolation of streptococci was associated with a 30% mortality and high rates of need for mechanical ventilatory and inotropic supports. Patients with GAS, SP or any streptococcal isolation had relative risks [95% confidence interval (CI), P value] of PICU deaths of 7.5 (CI 3.1-18.1, P 0.0001), 4.5 (CI 2.0-9.8, P 0.0002) and 5.7 (CI 3.4-9.5, P 0.0001), respectively. In SP, older children had significantly higher prevalence of premorbid conditions such as malignancy, mental retardation/cerebral palsy ± seizure disorders, chromosomal or genetic disorders (P = 0.003) than children5 years of age. Serotypes were available for some of these specimens that included 19A, 6B, 3 and 6C. There were four SP deaths with multiorgan system failure and hemolytic uremic syndrome (two 19A and two serotype 3).Severe streptococcal infections are associated with significant morbidity and mortality despite treatment with systemic antibiotics and intensive care unit support. GAS and SP affect the lungs of children, whereas GBS more likely causes meningitis in infants. The expanded coverage of newer polyvalent pneumococcal vaccines can probably prevent infections by serotypes 19A, 19F, 6B and 3.
- Published
- 2013
246. Geographically Structured Populations of Cryptococcus neoformans Variety grubii in Asia Correlate with HIV Status and Show a Clonal Population Structure
- Author
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Leo van Iersel, Kunyaluk Chaicumpar, Varaporn Vuddhakul, Pojana Sriburee, Weihua Pan, Ferry Hagen, Margaret Ip, Matthew C. Fisher, Ridhawati Sjam, Teun Boekhout, Wanqing Liao, Sitali P. Simwami, Retno Wahyuningsih, Saad J. Taj-Aldeen, Wieland Meyer, Darma Imran, Luciana Trilles, Kantarawee Khayhan, Ziauddin Khan, Reiko Ikeda, Corné H. W. Klaassen, Arunaloke Chakrabarti, Anuradha Chowdhary, Jacques F. Meis, and Evolutionary Intelligence
- Subjects
Asia ,Population ,Population genetics ,lcsh:Medicine ,HIV Infections ,Gene flow ,03 medical and health sciences ,medicine ,Humans ,education ,lcsh:Science ,030304 developmental biology ,Cryptococcus neoformans ,Genetics ,0303 health sciences ,Genetic diversity ,education.field_of_study ,Multidisciplinary ,biology ,Geography ,030306 microbiology ,Ecology ,Haplotype ,lcsh:R ,Pathogenesis and modulation of inflammation Infection and autoimmunity [N4i 1] ,biology.organism_classification ,medicine.disease ,3. Good health ,Cryptococcosis ,Multilocus sequence typing ,lcsh:Q ,Research Article - Abstract
Contains fulltext : 125490.pdf (Publisher’s version ) (Open Access) Cryptococcosis is an important fungal disease in Asia with an estimated 140,000 new infections annually the majority of which occurs in patients suffering from HIV/AIDS. Cryptococcus neoformans variety grubii (serotype A) is the major causative agent of this disease. In the present study, multilocus sequence typing (MLST) using the ISHAM MLST consensus scheme for the C. neoformans/C. gattii species complex was used to analyse nucleotide polymorphisms among 476 isolates of this pathogen obtained from 8 Asian countries. Population genetic analysis showed that the Asian C. neoformans var. grubii population shows limited genetic diversity and demonstrates a largely clonal mode of reproduction when compared with the global MLST dataset. HIV-status, sequence types and geography were found to be confounded. However, a correlation between sequence types and isolates from HIV-negative patients was observed among the Asian isolates. Observations of high gene flow between the Middle Eastern and the Southeastern Asian populations suggest that immigrant workers in the Middle East were originally infected in Southeastern Asia.
- Published
- 2013
247. Seroprevalence of Antibody to Severe Acute Respiratory Syndrome (SARS)-Associated Coronavirus among Health Care Workers in SARS and Non-SARS Medical Wards
- Author
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Louis Yik-Si Chan, Alan Wu, Tony K. C. Ng, Joseph J.Y. Sung, H. M. Kwan, John S. Tam, Lily Tsang, Albert Ng, Paul K.S. Chan, Jo L.K. Cheung, Ida Chu, Margaret Ip, and Nelson Lee
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,Infectious Disease Transmission, Patient-to-Professional ,Health Personnel ,health care facilities, manpower, and services ,Antibodies, Viral ,Severe Acute Respiratory Syndrome ,medicine.disease_cause ,Health personnel ,Seroepidemiologic Studies ,Occupational Exposure ,Health care ,medicine ,Humans ,Seroprevalence ,Abstracts for Electronic Articles ,skin and connective tissue diseases ,Subclinical infection ,Coronavirus ,biology ,Infectious disease transmission ,business.industry ,fungi ,virus diseases ,medicine.disease ,body regions ,Infectious Diseases ,Severe acute respiratory syndrome-related coronavirus ,Immunology ,Emergency medicine ,biology.protein ,Hong Kong ,Brief Reports ,Severe acute respiratory syndrome ,Antibody ,business ,Hospital Units - Abstract
The seroprevalence of antibody to severe acute respiratory syndrome (SARS)–associated coronavirus (SARS-CoV) in cohorts of health care workers (HCWs) with subclinical infection in SARS and non-SARS medical wards was 2.3% (3 of 131 HCWs) and 0% (0 of 192 HCWs), respectively. Rates for clinical SARS-CoV infection among 742 HCWs on these wards were highest among nurses (11.6%) and health care assistants (11.8%), indicating that these occupations are associated with the highest risks for exposure.
- Published
- 2004
248. Increased nasopharyngeal carriage of serotypes 6A, 6C, and 6D Streptococcus pneumoniae after introduction of childhood pneumococcal vaccination in Hong Kong
- Author
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Margaret Ip, Shirley S.L. Chau, E. Anthony S. Nelson, Paul K.S. Chan, Helen Ma, and Lui Sau Lai
- Subjects
Microbiology (medical) ,Serotype ,Male ,medicine.medical_specialty ,Cefotaxime ,Nasopharyngeal carriage ,Microbial Sensitivity Tests ,Penicillins ,medicine.disease_cause ,Pneumococcal Infections ,Isolation rate ,Pneumococcal Vaccines ,Internal medicine ,Nasopharynx ,Streptococcus pneumoniae ,medicine ,Humans ,Prospective Studies ,Serotyping ,Child ,Vaccines, Conjugate ,business.industry ,Vaccination ,General Medicine ,Virology ,Anti-Bacterial Agents ,Infectious Diseases ,Carriage ,Child, Preschool ,Pneumococcal vaccination ,Acute Disease ,Hong Kong ,Female ,business ,medicine.drug - Abstract
Active surveillance on nasopharygeal carriage of Streptococcus pneumoniae in children was conducted in 5581 children under 16 years old admitted with respiratory illness to the pediatric wards in a Hong Kong teaching hospital during 2008-2010. The isolation rate of S. pneumoniae was 14.5%. The most common serotypes/groups from 911 isolates were 19F, 6B, 23F, 14, 6C, 6A, and 3. Considering only children under 2 years old, the percentage serotype belonging to that of the 7-, 10- and 13-valent conjugate pneumococcal vaccines in S. pneumoniae were 56.0% (115/205), 57% (117/205), and 80.5% (165/205), respectively. The prevalence of penicillin-nonsusceptibility (MIC ≥4.0 μg/mL) was 9.1% and for cefotaxime (MIC ≥2.0 μg/mL) was 14.7%. A high prevalence of non-6B serotype, including 6A, 6C, and 6D was noted after the introduction of PCV7 conjugate pneumococcal vaccines in Hong Kong.
- Published
- 2012
249. Role of atypical pathogens in nursing home-acquired pneumonia
- Author
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David S.C. Hui, Hon Ming Ma, Margaret Ip, Paul K.S. Chan, Elsie Hui, and Jean Woo
- Subjects
Male ,medicine.medical_specialty ,Mycoplasma pneumoniae ,medicine.drug_class ,Antibiotics ,Bacteriuria ,medicine.disease_cause ,Statistics, Nonparametric ,Article ,Serology ,Anti-Infective Agents ,Nasopharyngeal aspirate ,Risk Factors ,Internal medicine ,medicine ,Prevalence ,Humans ,Prospective Studies ,Intensive care medicine ,General Nursing ,Aged ,Aged, 80 and over ,Cross Infection ,Chi-Square Distribution ,aspiration ,business.industry ,Nursing home ,Health Policy ,atypical pathogens ,General Medicine ,Pneumonia ,medicine.disease ,Nursing Homes ,Chlamydophila pneumoniae ,Sputum ,Female ,Geriatrics and Gerontology ,medicine.symptom ,business - Abstract
Objectives No international consensus has been reached on the empirical use of antibiotics with atypical coverage in nursing home–acquired pneumonia (NHAP). Aspiration is an important cause of NHAP, but it may not require antimicrobial treatment. This study aimed to investigate the prevalence and clinical characteristics of AP infections and review the need for empirical antibiotics with atypical coverage in NHAP. Design A prospective cohort study. Setting Four nursing homes with a total number of 772 residents. Participants Patients were aged ≥ 65 years, hospitalized for NHAP, which was defined as the presence of respiratory symptoms and abnormal chest radiographs, from April 2006 to March 2007. Measurements Demographics, clinical parameters, and investigation results were recorded. Microbial investigations comprised sputum routine and mycobacterial cultures, blood and urine cultures, serology, and nasopharyngeal aspirate viral culture and polymerase chain reaction tests. Suspected aspiration pneumonitis was arbitrarily defined as NHAP without pathogens identified. Results After excluding lone bacteriuria, 108 episodes of NHAP in 94 patients were included. Twelve APs were detected in 11 patients. There was no clinical feature to distinguish between infections caused by APs and other pathogens. The commonest APs were Mycoplasma pneumoniae (6) and Chlamydophila pneumoniae (3). No Legionella pneumophila was detected by urinary antigen test. None of the patients with AP infection received antibiotics indicated for AP infections. However, AP infections did not result in mortality. No pathogen was isolated in 31.5% of cases. Patients without pathogens isolated were less likely to have purulent sputum and crepitations on chest auscultation, compared with those with pneumonia caused by identified pathogens. Conclusions Atypical pathogens (APs) were not associated with mortality even in cases where the prescribed antibiotics did not cover APs. NHAP may not necessarily be treated with empirical antibiotics covering APs.
- Published
- 2012
250. Pneumococcus 'die hard'
- Author
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K L, Hon, Margaret, Ip, Terene P Y, Ma, and Winnie C W, Chu
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Male ,Pneumococcal Vaccines ,Humans ,Infant ,Immunization ,Pneumococcal Infections - Published
- 2012
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