Search

Although almost all mycobacterial species are saprophytic environmental organisms, a few, such as Mycobacterium tuberculosis , have evolved to cause transmissible human infection. By analyzing the recent emergence and spread of the environmental organism M. abscessus through the global cystic fibrosis population, we have defined key, generalizable steps involved in the pathogenic evolution of mycobacteria. We show that epigenetic modifiers, acquired through horizontal gene transfer, cause saltational increases in the pathogenic potential of specific environmental clones. Allopatric parallel evolution during chronic lung infection then promotes rapid increases in virulence through mutations in a discrete gene network; these mutations enhance growth within macrophages but impair fomite survival. As a consequence, we observe constrained pathogenic evolution while person-to-person transmission remains indirect, but postulate accelerated pathogenic adaptation once direct transmission is possible, as observed for M. tuberculosis Our findings indicate how key interventions, such as early treatment and cross-infection control, might restrict the spread of existing mycobacterial pathogens and prevent new, emergent ones., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Data regarding the comparative profiling of HCAP and HAP from developing countries like India are scant. We set out to address the microbial aetiology, antibiotic resistance and treatment outcomes in patients with HCAP and HAP., Methods: 318 consenting patients with HCAP (n = 165, aged 16-90 years; median 60 years; 97 males) or HAP (n = 153; aged 16-85 years; median 45 years; 92 males) presenting to a tertiary care hospital in North India from 2013 to 2015 were prospectively recruited for the study. Data on patient characteristics, microbial aetiology, APACHE II scores, treatment outcomes and mortality were studied. Clinical outcomes were compared with various possible predictors employing logistic regression analysis., Results: Patients in HCAP had more comorbidity. Escherichia coli (30, 18%) and Acinetobacter baumannii (62, 41%) were the most commonly isolated bacteria in HCAP and HAP, respectively. Multidrug-resistant bacteria were isolated more frequently in HCAP, only because the incidence of extensively drug-resistant bacteria was markedly high in HAP (p = 0.00). The mean APACHE II score was lower in HCAP (17.55 ± 6.406, range 30) compared to HAP (19.74 ± 8.843, range 37; p = 0.013). The length of stay ≥ 5 days (p = 0.036) and in-hospital mortality was higher in HAP group (p = 0.002). The most reliable predictors of in-hospital mortality in HCAP and HAP were APACHE II score ≥ 17 (OR = 14, p = 0.00; HAP: OR = 10.8, p = 0.00), and septic shock (OR = 4.5, p = 0.00; HAP: OR = 6.9, p = 0.00)., Conclusion: The patient characteristics in HCAP, treatment outcomes, bacterial aetiology, and a higher incidence of antibiotic-resistant bacteria, suggest that HCAP although not as severe as HAP, can be grouped as a separate third entity.

We report the case of a 35-year-old quadriplegic male with confirmed Bordetella bronchiseptica pneumonia, manifesting with acute hypoxic respiratory failure on a background of chronic hypercarbia requiring mechanical ventilation in intensive care. B. bronchiseptica are known to colonise the upper respiratory tracts of many mammals but are very rarely responsible for acute respiratory tract infections in humans.A review of the literature suggests preponderance for immunocompromised or immunoincompetent patients who have experienced environmental exposure to colonised animals. The disease pattern of B. bronchiseptica infection is non-uniform and while it is rarely described as a commensal or colonising organism, very few case reports describe severe respiratory infections., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Rationale: Ventilator-associated pneumonia (VAP) is the most common nosocomial infections in patients admitted to the ICU. The adapted island model predicts several changes in the respiratory microbiome during intubation and mechanical ventilation., Objectives: We hypothesised that mechanical ventilation and antibiotic administration decrease the diversity of the respiratory microbiome and that these changes are more profound in patients who develop VAP., Methods: Intubated and mechanically ventilated ICU-patients were included. Tracheal aspirates were obtained three times a week. 16S rRNA gene sequencing with the Roche 454 platform was used to measure the composition of the respiratory microbiome. Associations were tested with linear mixed model analysis and principal coordinate analysis., Measurements and Main Results: 111 tracheal aspirates were obtained from 35 patients; 11 had VAP, 18 did not have VAP. Six additional patients developed pneumonia within the first 48 hours after intubation. Duration of mechanical ventilation was associated with a decrease in α diversity (Shannon index; fixed-effect regression coefficient (β): -0.03 (95% CI -0.05 to -0.005)), but the administration of antibiotic therapy was not (fixed-effect β: 0.06; 95% CI -0.17 to 0.30). There was a significant difference in change of β diversity between patients who developed VAP and control patients for Bray-Curtis distances (p=0.03) and for Manhattan distances (p=0.04). Burkholderia, Bacillales and, to a lesser extent, Pseudomonadales positively correlated with the change in β diversity., Conclusion: Mechanical ventilation, but not antibiotic administration, was associated with changes in the respiratory microbiome. Dysbiosis of microbial communities in the respiratory tract was most profound in patients who developed VAP., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

We investigated the molecular epidemiology and microbiological characteristics of 51 Escherichia coli isolates causing hospital-acquired pneumonia (HAP) in eight Asian areas. Sequence type 131 (ST131) was the most prevalent among E. coli isolates causing HAP, especially in South Korea, Thailand, and the Philippines. The current study showed that CTX-M-15-producing E. coli ST131 has emerged in and disseminated among patients with HAP in Asia. Our data suggest that this pandemic clone poses an important public health threat even in nosocomial infections.

Lung infections with Mycobacterium abscessus, a species of multidrug-resistant nontuberculous mycobacteria, are emerging as an important global threat to individuals with cystic fibrosis (CF), in whom M. abscessus accelerates inflammatory lung damage, leading to increased morbidity and mortality. Previously, M. abscessus was thought to be independently acquired by susceptible individuals from the environment. However, using whole-genome analysis of a global collection of clinical isolates, we show that the majority of M. abscessus infections are acquired through transmission, potentially via fomites and aerosols, of recently emerged dominant circulating clones that have spread globally. We demonstrate that these clones are associated with worse clinical outcomes, show increased virulence in cell-based and mouse infection models, and thus represent an urgent international infection challenge., (Copyright © 2016, American Association for the Advancement of Science.)

Background: Tracheal tube biofilm develops during mechanical ventilation. We compared a novel closed-suctioning system vs standard closed-suctioning system in the prevention of tracheal tube biofilm., Methods: Eighteen pigs, on mechanical ventilation for 76 h, with P. aeruginosa pneumonia were randomized to be tracheally suctioned via the KIMVENT* closed-suctioning system (control group) or a novel closed-suctioning system (treatment group), designed to remove tracheal tube biofilm through saline jets and an inflatable balloon. Upon autopsy, two tracheal tube hemi-sections were dissected for confocal and scanning electron microscopy. Biofilm area, maximal and minimal thickness were computed. Biofilm stage was assessed., Results: Sixteen animals were included in the final analysis. In the treatment and control group, the mean (sd) pulmonary burden was 3.34 (1.28) and 4.17 (1.09) log cfu gr(-1), respectively (P=0.18). Tracheal tube P. aeruginosa colonization was 5.6 (4.9-6.3) and 6.2 (5.6-6.9) cfu ml(-1) (median and interquartile range) in the treatment and control group, respectively (P=0.23). In the treatment group, median biofilm area was 3.65 (3.22-4.21) log10 μm2 compared with 4.49 (4.27-4.52) log10 μm2 in the control group (P=0.031). In the treatment and control groups, the maximal biofilm thickness was 48.3 (26.7-71.2) µm (median and interquartile range) and 88.8 (43.8-125.7) µm, respectively. The minimal thickness in the treatment and control group was 0.6 (0-4.0) µm and 23.7 (5.3-27.8) µm (P=0.040) (P=0.017). Earlier stages of biofilm development were found in the treatment group (P<0.001)., Conclusions: The novel CSS reduces biofilm accumulation within the tracheal tube. A clinical trial is required to confirm these findings and the impact on major outcomes., (© The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose of Review: We present the key advances in the infections that clinicians conventionally associate with atypical pneumonia: legionellosis, Mycoplasma pneumonia, Chlamydophila species pneumonia and Q fever., Recent Findings: There have been significant developments in molecular diagnosis to include Mycoplasma pneumoniae and Chlamydophila pneumoniae in multiplex PCR of respiratory specimens. There are diagnostic challenges in distinguishing carriage from infection, which is recognized in C. pneumoniae and now also evident in M. pneumoniae. Macrolide-resistant M. pneumoniae has emerged in Asia. There are new antimicrobials on the horizon in the ketolide class with activity against typical and atypical pathogens and useful empirical agents., Summary: There are few advances in our knowledge of the epidemiology of atypical pathogens or the effectiveness of antimicrobial therapy--empirical or pathogen specific. However, if molecular testing becomes widely implemented, there will be an increased understanding of the epidemiology and presentation of atypical pneumonia and a shift to more targeted antimicrobial therapy.

Background: Q fever is a common cause of febrile illness and community-acquired pneumonia in resource-limited settings. Coxiella burnetii, the causative pathogen, is transmitted among varied host species, but the epidemiology of the organism in Africa is poorly understood. We conducted a systematic review of C. burnetii epidemiology in Africa from a "One Health" perspective to synthesize the published data and identify knowledge gaps., Methods/principal Findings: We searched nine databases to identify articles relevant to four key aspects of C. burnetii epidemiology in human and animal populations in Africa: infection prevalence; disease incidence; transmission risk factors; and infection control efforts. We identified 929 unique articles, 100 of which remained after full-text review. Of these, 41 articles describing 51 studies qualified for data extraction. Animal seroprevalence studies revealed infection by C. burnetii (≤13%) among cattle except for studies in Western and Middle Africa (18-55%). Small ruminant seroprevalence ranged from 11-33%. Human seroprevalence was <8% with the exception of studies among children and in Egypt (10-32%). Close contact with camels and rural residence were associated with increased seropositivity among humans. C. burnetii infection has been associated with livestock abortion. In human cohort studies, Q fever accounted for 2-9% of febrile illness hospitalizations and 1-3% of infective endocarditis cases. We found no studies of disease incidence estimates or disease control efforts., Conclusions/significance: C. burnetii infection is detected in humans and in a wide range of animal species across Africa, but seroprevalence varies widely by species and location. Risk factors underlying this variability are poorly understood as is the role of C. burnetii in livestock abortion. Q fever consistently accounts for a notable proportion of undifferentiated human febrile illness and infective endocarditis in cohort studies, but incidence estimates are lacking. C. burnetii presents a real yet underappreciated threat to human and animal health throughout Africa.

Background: Health care-associated pneumonia (HCAP) affects a heterogeneous group of patients in frequent contact with health care systems. However, HCAP criteria poorly predict infection with drug-resistant (DR) pathogens., Objective: To validate our previously reported risk-scoring model (predictive of DR pathogen infection) in patients admitted to hospital with pneumonia., Design: We evaluated 580 patients admitted with culture-positive bacterial pneumonia. We identified risk factors, evaluated the risk-scoring model's capacity to predict infection by DR pathogens and compared the model's diagnostic accuracy with that of current HCAP criteria., Results: DR pathogens were observed in 227/580 patients (39.1%). Of 269 HCAP patients, 153 (56.9%) were infected with DR pathogens. Overtreatment was more common in HCAP than in community-acquired pneumonia (58.7% vs. 41.2%, P < 0.001). Recent hospitalisation, admission from a long-term care facility, recent antibiotic treatment and tube feeding were independently associated with DR pathogens. For pathogen prediction, the risk-scoring model showed better diagnostic accuracy than HCAP criteria (area under receiver operating-characteristic curve = 0.723 vs. 0.673, P < 0.001)., Conclusion: According to current HCAP criteria, half of the HCAP patients were treated unnecessarily with broad-spectrum antibiotics. Risk scoring by stratifying risk factors could improve the identification of patients likely to be infected with DR pathogens.

Background: The incidence of hospital acquired pneumonia (HAP) varies according to the type of intensive care units (ICUs)., Aim: The aims of this study were to determine the frequency of hospital acquired pneumonia (HAP) and the effect of isolation rooms on the frequency of pneumonia in the ICU., Materials and Methods: The present investigation was carried out between January 2004 and July 2008. The ICU, which was 4-bed ward-type between January 2004 and February 2006 (1st period), was reconfigured as isolated rooms with only 2 beds each after March 2006 (2nd period). 153 and 379 patients were followed up in the ICU in the 1st and 2nd periods, respectively. Blood, sputum, and deep tracheal aspiration cultures were used for the isolation of the causative agents., Results: No significant difference was detected between the general characteristics of patients. HAP developed in 101 patients (19%). The prevalence of HAP was 22.9% in the 1st period and 17.4% in the 2nd period. During the 1st and 2nd periods, the HAP infection densities were 22.2 and 16.1/1000 patient-days and the ventilator-associated pneumonia densities were 48.1 and 37.6/1000 ventilator-days, respectively. Eighty-six percent of HAP was ventilator-associated pneumonia (VAP)., Conclusions: Isolation rooms in the ICU may be an effective strategy to control and decrease the rate of pneumonia in the ICU in addition to other preventive strategies.

Rhodococcus equi pneumonia is a worldwide infectious disease of major concern to the equine breeding industry. The disease typically manifests in foals as pyogranulomatous bronchopneumonia, resulting in significant morbidity and mortality. Inhalation of aerosolised virulent R. equi from the environment and intracellular replication within alveolar macrophages are essential components of the pathogenesis of R. equi pneumonia in the foal. Recently documented evidence of airborne transmission between foals indicates the potential for an alternative contagious route of disease transmission. In the first of this two-part review, the complexity of the host, pathogen and environmental interactions that underpin R. equi pneumonia will be discussed through an exploration of current understanding of the epidemiology and pathogenesis of R. equi pneumonia in the foal., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To determine differences in aetiologies, initial antimicrobial treatment choices and outcomes in patients with nursing-home-acquired pneumonia (NHAP) compared with patients with community-acquired pneumonia (CAP), which is a controversial issue., Methods: Data from the prospective multicentre Competence Network for Community-acquired pneumonia (CAPNETZ) database were analysed for hospitalised patients aged ≥65 years with CAP or NHAP. Potential differences in baseline characteristics, comorbidities, physical examination findings, severity at presentation, initial laboratory investigations, blood gases, microbial investigations, aetiologies, antimicrobial treatment and outcomes were determined between the two groups., Results: Patients with NHAP presented with more severe pneumonia as assessed by CRB-65 (confusion, respiratory rate, blood pressure, 65 years and older) score than patients with CAP but received the same frequency of mechanical ventilation and less antimicrobial combination treatment. There were no clinically relevant differences in aetiology, with Streptococcus pneumoniae the most important pathogen in both groups, and potential multidrug-resistant pathogens were very rare (<5%). Only Staphylococcus aureus was more frequent in the NHAP group (n=12, 2.3% of the total population, 3.1% of those with microbial sampling compared with 0.7% and 0.8% in the CAP group, respectively). Short-term and long-term mortality in the NHAP group was higher than in the CAP group for patients aged ≥65 years (26.6% vs 7.2% and 43.8% vs 14.6%, respectively). However, there was no association between excess mortality and potential multidrug-resistant pathogens., Conclusions: Excess mortality in patients with NHAP cannot be attributed to a different microbial pattern but appears to result from increased comorbidities, and consequently, pneumonia is frequently considered and managed as a terminal event.

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40–60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.

Background & Objectives: The congregation of a large number of people during Hajj seasons from different parts of the world in overcrowded conditions within a confined area for a long period of time presents many public health challenges and health risks. One of the main health problems of the crowding is ease transmission of pneumonia by air droplets. This study was aimed to determine the most common causes of bacterial pneumonia during the 2005 Hajj season and to relate the findings with clinical conditions., Methods: A total of 141 patients with suspected pneumonia from the three main tertiary care hospitals in Makkah, Saudi Arabia, were investigated during Hajj season, 2005. Sputum and serum samples were collected and investigated for the possible presence of typical or atypical causative agents., Results: Of the 141 clinically suspected pneumonia cases, 76 (53.9%) were confirmed positive by microbiological tests. More than 94 per cent of the confirmed cases were in the age group >50 yr, and 56.6 per cent of the cases were men. The most frequent isolates were Candida albicans (28.7%) and Pseudomonas aeruginosa (21.8%), followed by Legionella pneumophila (14.9%) and Klabsiella pneumoniae (9.2%). More than one causative pathogens were isolated in 15 patients (16.3%), and 55 per cent of patients were diabetic., Interpretation & Conclusions: Clinicians should be aware that typical pneumonia treatment regimens may not work well during the Hajj season due to the wide variety of isolated organisms. This necessitates taking a sputum sample before starting treatment for identification and sensitivity testing. Special precautions need to be taken for >50 yr old patients.

Health care-acquired pneumonia (HAP) is associated with significant morbidity and mortality. These infections most frequently arise from a patient's indigenous flora, although occasionally they result from exposure to environmental pathogens such as Legionella and Aspergillus. This article reviews infection prevention strategies to reduce the incidence of HAP. Successful implementation of these prevention strategies usually requires a multidisciplinary approach and standardization of protocols. This article also discusses strategies to prevent transmission of Mycobacterium tuberculosis within health care settings., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Ventilator-associated pneumonia (VAP) is an important nosocomial infection at neonatal intensive care units (NICU), frequently caused by Pseudomonas aeruginosa. A 6-month prospective study from January 2009 through June 2009 was performed to investigate the respective contribution of endogenous and exogenous transmission of P aeruginosa in the respiratory colonization or/and infection in the mechanically ventilated patients at a NICU to identify routes of lung infection with P aeruginosa and to assess risk factors for colonization or respiratory infection with P aeruginosa., Methods: Samples from oropharyngeal swab, tracheobronchial aspirates, gastric aspirate, and rectal swab were obtained in each patient after intubation and then twice a week. Surveillance cultures for the presence of P aeruginosa from environmental surfaces of the ICU were taken once every 5 days during the study period. Pulsed-field gel electrophoresis was used to characterize the clonal relatedness of the strains by SpeI-digested genomic DNA., Results: Eighteen patients (78.3%) had colonization of the upper respiratory tract. Sixteen (69.6%) patients with colonization of the respiratory tract were infected from other patients or environmental surfaces, which was considered exogenous, and, among strains causing pulmonary infection, there were 4 (50%) patients with exogenous infection. Eight of these developed VAP after a mean of 9 ± 3.4 days. The incidence of P aeruginosa VAP on the unit was 6.2%. The respiratory tract was the earliest site of colonization in all patients of VAP. Low birth weight, duration of mechanical ventilation, previous ampicillin group use, and previous second-generation cephalosporins use were independently associated with patient-related acquisition of P aeruginosa., Conclusion: Our results confirm that the upper respiratory tract acts as an important reservoir of P aeruginosa colonization and infection in the mechanically ventilated patients and emphasize the importance of exogenous acquisition of P aeruginosa. A combination of early identification and eradication of airways colonization by P aeruginosa plus infection control measures may be the basis to prevent pulmonary infection., (Copyright © 2010 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

Pasteurella multocida is a non-motile, faculatively-anaerobic, gram-negative bacillus associated with a spectrum of human disease. Direct and indirect zoonotic transmission is recognised with animal bites being most frequently encountered as a result of salivary colonisation in farm and domestic animals. Despite the prevalence of P. multocida in swine herds, the relationship between porcine colonisation and human disease is poorly established. This lesson reports a previously unrecognised mode of zoonotic transmission in respiratory pasteurellosis; domestic cooking of pig trotters.

The incidence of Acinetobacter baumannii pneumonia in hospital-acquired pneumonia in Japan is rare. We report a case of ventilator-associated A. baumanii pneumonia. A 69-year-old man admitted for fever was diagnosed with Streptococcus pneumoniae pneumonia based on chest radiography, urine antigen, and sputum examination. Despite appropriate antibiotics, the pneumonia progressed, necessitating intensive respiratory management. Ten days there after, he suffered sudden septic shock and superimposed pneumonia despite both carbapenem and fluoroquinolone administration. A. baumanii was detected from blood and sputum. Piperacilline/tazobactam, amikacin, and intensive care saved his life.

Background: Pneumonia among nursing home (NH) residents has increased considerably in recent years, but it remains unclear whether it should be considered as community-acquired pneumonia (CAP) or a new category of infection., Methods: 150 consecutive cases of NH-acquired pneumonia (NHAP) (from 1 February 1997 to 1 July 2007) were analysed., Results: Patients (median age, 82 years; range, 77-87 years) showed numerous co-morbidities, (neurological, 55%; pulmonary, 38%; cardiac, 35%) and severe disability for daily activities (partial, 32%; total, 31%). Cases of NHAP were mainly classified as mild to moderate according to the CRB-65 score (CRB-65 classes 0-1 and 2, 41% each). In-hospital and 30-day mortality were 8.7% and 20%, respectively. Aetiology was defined in 57 cases (38%). The most common isolates were Streptococcus pneumoniae (58%), Enterobacteriaceae (Gram-negative bacteria (GNB)) (9%), atypical bacteria (7%), respiratory viruses (5%), methicillin-resistant Staphylococcus aureus (MRSA) (5%) and Legionella pneumophila (5%). The most frequent causes of treatment inadequacy were use of beta-lactams alone (25%) and lack of aspiration assessment (15%). Prognostic factors of 1-month mortality were neurological comorbidities (OR 4.5; 95% CI 1.3 to 15.7; p=0.020), septic shock (OR 6.6; 95% CI 1.3 to 34.0; p=0.025), pleural effusion (OR 3.6; 95% CI 1.1 to 11.7; p=0.036) and isolation of GNB or MRSA (OR 16.4; 95% CI 2.1 to 128.9; p=0.008)., Conclusions: The patients show clinical characteristics (eg, age and co-morbidities) comparable with those with hospital-acquired pneumonia. However, microbiological and mortality data of patients with NHAP are more similar to the data of those with CAP. Isolation of GNB or MRSA was associated with increased mortality risk. CAP empirical antibiotic coverage is still indicated in NHAP, although specific risk factors for multidrug-resistant infections should be assessed on an individual basis.

Exposure of healthcare workers to patients with rapidly fatal infections invariably raises concerns regarding the risk of occupational acquisition. We describe acquisition of Streptococcus pyogenes by 2 nurses from a patient with fatal pneumonia and review previously reported cases of transmission of bacterial pathogens from patients with pneumonia to healthcare workers.

Objectives: The impact of time-dependent exposures on the time until study endpoint may correctly be analyzed with data of a full cohort. Ignoring the time-dependent nature of these exposures leads to time-dependent bias. Matching for time to exposure is often applied to take the time-dependency into account, but prefixed sets of exposed and unexposed may still create bias. This approach is attractive since a subcohort would also save resources, especially when exposure and outcome data are only available in the full cohort but further covariate information is required. The first objective is to show to which extent matching for time to exposure yields biased results. Secondly, exposure density sampling is introduced and explored., Methods: To evaluate how both sampling methods perform, they are compared to the correct method as well as to the approach in which the time-dependent nature of the exposure is ignored. Real data of the SIR-3 study (Germany, 2000-2001) and a simulation study are used., Results: Simulations show that matching may reduce the time-dependent bias but still there is a bias. The matching bias decreases if fewer patients are exposed. Exposure density sampling yields unbiased results., Conclusions: Results from studies in which matching for time to exposure was applied are only tolerable for rare exposures. Whenever subcohorting is the intention in order to save resources, exposure density sampling should be preferred instead.

Background: Acinetobacter baumannii is increasingly recognized as being a significant pathogen associated with nosocomial outbreaks in both civilian and military treatment facilities. Current analyses of these outbreaks frequently describe patient-to-patient transmission. To date, occupational transmission of A. baumannii from a patient to a health care worker (HCW) has not been reported. We initiated an investigation of an HCW with a complicated case of A. baumannii pneumonia to determine whether a link existed between her illness and A. baumannii-infected patients in a military treatment facility who had been entrusted to her care., Methods: Pulsed-field gel electrophoresis and polymerase chain reaction/electrospray ionization mass spectrometry, a form of multilocus sequencing typing, were done to determine clonality. To further characterize the isolates, we performed a genetic analysis of resistance determinants., Results and Conclusions: A "look-back" analysis revealed that the multidrug resistant A. baumannii recovered from the HCW and from a patient in her care were indistinguishable by pulsed-field gel electrophoresis. In addition, polymerase chain reaction/electrospray ionization mass spectrometry indicated that the isolates were similar to strains of A. baumannii derived from European clone type II (Walter Reed Army Medical Center strain type 11). The exposure of the HCW to the index patient lasted for only 30 min and involved endotracheal suctioning without use of an HCW mask. An examination of 90 A. baumannii isolates collected during this investigation showed that 2 major and multiple minor clone types were present and that the isolates from the HCW and from the index patient were the most prevalent clone type. Occupational transmission likely occurred in the hospital; HCWs caring for patients infected with A. baumannii should be aware of this potential mode of infection spread.

We report a case of community acquired methicillin resistant Staphylococcus aureus pneumonia. The causative organism was positive for the toxin Panton-Valentine Leukocidin. This resulted in a severe pneumonia requiring a prolonged stay on our intensive care unit. This infection is becoming more common in the United Kingdom. It can cause a far more aggressive illness than the hospital acquired infection with a high mortality if it becomes an invasive infection. The Department of Health has recently produced interim guidelines for its treatment which we have also reviewed.

Pneumonia is a medical and public health priority, and advances against this disease will require improved knowledge of biological mechanisms. Human pneumonia is modeled with experimental infections of animals, most frequently mice. Mouse models are leading to important discoveries relevant to pneumonia, but their limitations must be carefully considered. Several approaches to establishing pneumonia in mice have been developed, and each has specific strengths and weaknesses. Similarly, procedures for characterizing microbial and host responses to infection have unique advantages and disadvantages. Mice are not small humans, and the applicability of results from murine models to human disease depends on understanding the similarities and differences between species. Additional considerations such as mouse strain, microbe strain, and prior mouse-microbe interactions also influence the design and interpretation of experiments. Results from studies of pneumonia in animals, combined with complementary basic and translational studies, are elucidating mechanisms responsible for susceptibility to and pathophysiology of lung infection.

We report the case of a patient with pneumonia caused by Pasteurella multocida (P. multocida). An 83-year-old woman admitted for bronchiectasis, productive cough, and a high fever was found in chest radiography on admission to have a new infiltrative shadow in the left lower lung field. Chest computed tomography indicated bilateral bronchiectasis and an infiltrative lingular shadow. P. multocida was isolated from sputum samples. Biapenem and minocycline therapy ameliorated symptoms. Pulsed-field gel electrophoresis (PFGE) showed that the clinical isolate recovered was identical to the P. multocida isolate recovered from the pharyngeal swab specimen culture obtained from the patient's dog. Several years later, P. multocida subsp. gallicida isolates were recovered from human sputum and a canine pharyngeal swab specimen. PFGE confirmed these isolates to be identical and PFGE band patterns were identical to those of previous P. multocida isolates. These findings suggest that P. multocida was transmitted from the patient's dog to the patient and underscore the need to inform susceptible hosts at risk of contracting zoonotic agents about basic hygiene rules for keeping pets. PFGE data strengthened the evidence of zoonotic transmission of P. multocida through casual contact in a patient with a respiratory infection caused by this organism. PFGE should prove useful in both epidemiological tracing and preventing pasteurellosis and clarifying its pathology. Case reports of respiratory infections including pneumonia caused by P. multocida are increasing in humans, and P. multocida respiratory infections appear to occur mostly in patients with chronic respiratory disease. A history of pet exposure, even without bites or scratches, should alert the physician to P. multocida as a potential respiratory pathogen.

We described a case of chest wall dissemination after percutaneous transthoracic needle biopsy. A 65-year-old man had a lung nodule which was suspected to be lung carcinoma. He underwent percutaneous transthoracic needle biopsy using an 18G semiautomated biopsy needle and pathologic diagnosis showed organizing pneumonia. Two months after the biopsy, chest wall dissemination occurred. Implantation of carcinoma along the biopsy route was suspected, but the mass was actually due to pulmonary nocardiosis.

Panton-Valentine leukocidin-producing Staphylococcus aureus is an emerging pathogen world-wide, causing necrotizing lung infections in otherwise healthy individuals. We describe 2 episodes of patient-to-patient transmission of Panton-Valentine leukocidin-producing S. aureus, resulting in acute, life-threatening pulmonary complications in patients with cystic fibrosis. Appropriate infection control measures may be warranted to prevent similar episodes.

Objective: We evaluated whether Pseudomonas aeruginosa associated nosocomial infections in our ICU originate mainly from patients' endogenous flora or from exogenous cross-transmission., Design and Setting: A 6-month prospective surveillance survey was performed according to standardized protocols at the interdisciplinary ICU of the Azienda Ospedaliera Cannizzaro., Patients: The study analyzed 121 patients and focused on three different states: carriage upon admission, colonization of sterile sites, and infections during ICU stay., Results: We identified 138 P. aeruginosa isolates from 45 patients. The cumulative incidence of P. aeruginosa sustained colonization in the ICU was 29.9/100 patients, and the incidence density was 16.2/1,000 patient-days. The cumulative incidence of P. aeruginosa-sustained infections in the ICU was 36.7/100 patients, and the incidence density was 19.9/1,000 patient-days. The most frequent infection type was ventilator-associated pneumonia. PFGE analysis of P. aeruginosa isolates led to the identification of a major clone represented by 60.8% of isolates involving 45.9% of patients. The impact of cross-transmission, i.e., the preventable proportion of P. aeruginosa acquisition, was estimated to be at least 59.5% of all colonization or infection episodes. Acquisition of multidrug-resistant P. aeruginosa was significantly associated with cross-transmission., Conclusions: Our results suggest that the ICU personnel and environment served as reservoirs for cross-transmission and emphasize the importance of exogenous acquisition of multidrug-resistant P. aeruginosa, of reduction in antibiotic pressure, and prompt enforcement of infection control measures.

Community-acquired pneumonia (CAP) is a common illness, with the majority of patients treated out of the hospital, yet the greatest burden of the cost of care comes from inpatient management. In the past several years, the management of these patients has advanced, with new information about the natural history and prognosis of illness, the utility of serum markers to guide management, the use of appropriate clinical tools to guide the site-of-care decision, and the finding that guidelines can be developed in a way that improves patient outcome. The challenges to patient management include the emergence of new pathogens and the progression of antibiotic resistance in some of the common pathogens such as Streptococcus pneumoniae. Few new antimicrobial treatment options are available, and the utility of some new therapies has been limited by drug-related toxicity. Ancillary care for severe pneumonia with activated protein C and corticosteroids is being studied, but recently, inpatient care has been most affected by the development of evidence-based "core measures" for management that have been promoted by the Centers for Medicare and Medicaid Services, which form the basis for the public reporting of hospital performance in CAP care.

Objective: To identify factors contributing to a cluster of deaths from invasive group A streptococcus (GAS) infection in a nursing home facility and to prevent additional cases., Design: Outbreak investigation., Setting: A 146-bed nursing home facility in northern Nevada., Methods: We defined a case as the isolation of GAS from a normally sterile site in a resident of nursing home A. To identify case patients, we reviewed resident records from nursing home A, the local hospital, and the hospital laboratory. We obtained oropharyngeal and skin lesion swabs from staff and residents to assess GAS colonization and performed emm typing on available isolates. To identify potential risk factors for transmission, we performed a cohort study and investigated concurrent illness among residents and surveyed staff regarding infection control practices., Results: Six residents met the case patient definition; 3 (50%) of them died. Among invasive GAS isolates available for analysis, 2 distinct strains were identified: emm11 (3 isolates) and emm89 (2 isolates). The rate of GAS carriage was 6% among residents and 4% among staff; carriage isolates were emm89 (8 isolates), emm11 (2 isolates), and emm1 (1 isolate). Concurrently, 35 (24%) of the residents developed a respiratory illness of unknown etiology; 41% of these persons died. Twenty-one (30%) of the surveyed employees did not always wash their hands before patient contacts, and 27 (38%) did not always wash their hands between patient contacts., Conclusions: Concurrent respiratory illness likely contributed to an outbreak of invasive GAS infection from 2 strains in a highly susceptible population. This outbreak highlights the importance of appropriate infection control measures, including respiratory hygiene practices, in nursing home facilities.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most important diseases of cattle in Sub-Saharan Africa. The live T1/44 vaccine is normally used for its control but produces only transient protection and gives rise to adverse reactions. The present study evaluated the efficacy of danofloxacin (2.5% Advocintrade mark, Pfizer Ltd.) for the treatment of naturally infected cattle and in the prevention of CBPP transmission to in-contact cattle. Adult cattle, taken from a natural outbreak, were placed into two groups of 10 animals and kept on a research farm in paddocks 50m apart. One group was treated with 2.5mg/kg danofloxacin on days 0, 1 and 2; the other group were saline treated. On day 2, 10 CBPP-free, seronegative cattle were placed in contact with each of the two groups. All cattle were monitored for 3.5 months. No differences were seen in clinical improvement of the CBPP-affected cattle treated with danofloxacin compared with the untreated CBPP-affected cattle with approximately half of each group being withdrawn because of CBPP or showing CBPP lesions at post mortem examination. Clinical scores of the two groups were also similar. However cattle kept in contact with the danofloxacin-treated CBPP-affected animals showed significantly fewer lesions, less mortality and fewer animals were seropositive (P<0.02) and had reduced clinical scores (P<0.001) compared to cattle kept in contact with untreated CBPP-affected cattle. MmmSC was also isolated from fewer contact controls kept with the treated group. These findings could have important implications for the control of CBPP in Africa.

Objective: To determine the pathogens causing pneumonia in community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) and to investigate serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8) and CRP in pneumonia caused by different aetiological agents., Study Design: Eighty-seven children (mostly < 5 years of age) were recruited in a prospective study, 55 of them with CAP without prior antibiotic treatment and 32 with HAP. Thirty healthy outpatient children served as controls., Results: The causative micro-organisms were determined by serological and microbiological methods in 40 cases with CAP (72.7%) and 30 with HAP (93.7%). In CAP, M. pneumoniae was the most common causative agent (43.6%), followed by S. pneumoniae (20%) and C. pneumoniae (18.1%). Bacteria alone were the sole causative agents in only 21.8% of cases with HAP. Pseudomonas aeruginosa (34.3%) and K. pneumoniae (32.5%) were the most frequently isolated. Although IL-6 and IL-8 levels were raised, there was no statistical difference between the CAP and HAP groups, or between bacterial and mycoplasma infections; neither was there a difference in CRP levels between these two groups., Conclusion: The causes of pneumonia differ between CAP and HAP. Levels of IL-6, IL-8 and CRP are raised in pneumonia but are unhelpful in differentiating the various aetiologies.

The authors present the case of a 32 years male patient admitted for lung consolidations with bilateral extension tendency, associated to fever, respiratory failure and hepatic involvement, with a sudden onset two weeks after contact with apparently healthy parrots. Bronchiolo-alveolar lavage was suggestive for a hypersensitivity pneumonia, but the clinical evolution was good with antibiotics (macrolides, than doxycycline). Radiologic resolution was spectacular. Serum antibodies anti-ch. Psittaci were present in low titre, at the limit of significance. Final diagnosis was chlamydia psittaci pneumonia.

Purpose: To evaluate the clinical benefit of in-hospital observation after the switch from intravenous (IV) to oral antibiotics in a large Medicare population. Retrospective studies of relatively small size indicate that the practice of in-hospital observation after the switch from IV to oral antibiotics for patients hospitalized with community-acquired pneumonia (CAP) is unnecessary., Methods: We performed a retrospective examination of the US Medicare National Pneumonia Project database. Eligible patients were discharged with an ICD-9-CM diagnosis consistent with community-acquired pneumonia and divided into 2 groups: 1) a "not observed" cohort, in which patients were discharged on the same day as the switch from IV to oral antibiotics and 2) an "observed for 1 day" cohort, in which patients remained hospitalized for 1 day after the switch from IV to oral antibiotics. We compared clinical outcomes between these 2 cohorts., Results: A total of 39,242 cases were sampled, representing 4341 hospitals in all 50 states and the District of Columbia. There were 5248 elderly patients who fulfilled eligibility criteria involving a length of stay of no more than 7 hospital days (2536 "not observed" and 2712 "observed for 1 day" patients). Mean length of stay was 3.8 days for the "not observed" cohort and 4.5 days for the "observed for 1 day" cohort (P <.0001). There was no significant difference in 14-day hospital readmission rate (7.8% in the "not observed" cohort vs 7.2% "observed for 1 day" cohort, odds ratio 0.91; 95% confidence interval [CI] 0.74-1.12; P =.367) and 30-day mortality rate (5.1% "not observed" cohort vs 4.4% in the "observed for 1 day" cohort, odds ratio 0.86; 95% CI, 0.67-1.11; P =.258) between the "not observed" and "observed for 1 day" cohorts., Conclusions: Our analysis of the US Medicare Pneumonia Project database provides further evidence that the routine practice of in-hospital observation after the switch from IV to oral antibiotics for patients with CAP may be avoided in patients who are clinically stable although these findings should be verified in a large randomized controlled trial.

A 67-year-old man was admitted due to severe pneumonia. Initially he was treated with beta-lactam antibiotics and oxygen. However, he developed respiratory failure and was transferred to the intensive-care unit for mechanical ventilation. He was a bird-keeper who collected many species of exotic birds, including parrots. The diagnosis psittacosis (parrot fever) was confirmed serologically and by PCR on bronchoalveolar lavage fluid. PCR techniques lead to rapid diagnosis which allows for early treatment. The initial treatment of atypical pneumonia with ciprofloxacin failed. After the patient was treated with doxycycline 200 mg i.v. his clinical condition improved and he was cured. The patient was discharged from intensive care after 10 days when acute respiratory-distress syndrome and pericarditis had resolved. Psittacosis is seen sporadically in the Netherlands. It may be encountered more frequently among patients who have had contact with birds and should be considered in the differential diagnosis of atypical pneumonia.

In 1911, Lindner and colleagues identified intracytoplasmic inclusions in infants with a nongonococcal form of ophthalmia neonatorum called inclusion conjunctivitis of the newborn (ICN). Mothers of affected infants were found to have inclusions in their cervical epithelial cells, fathers of such infants had inclusions in their urethral cells, and the epidemiology of sexually transmitted chlamydial infections was revealed. Fifty years later, chlamydial isolation procedures were developed, and studies again demonstrated Chlamydia trachomatis as an etiology of ICN and the female birth canal as the reservoir. In the late 1970s, a report by Beem and Saxon described respiratory tract colonization and a distinct pneumonia syndrome in infected infants. Genital chlamydial infection is recognized as the world's most common sexually transmitted disease, with estimates of greater than 4 million new infections occurring annually in the United States. Although most C. trachomatis infections in men and women are asymptomatic, infection can lead to severe reproductive complications in women. The high prevalence in women of child-bearing age results in exposure of an estimated 100,000 neonates in the United States annually. Many of these infants develop conjunctivitis, pneumonia, or both in the first few months of life. Clinical features, diagnosis, treatment, and approaches to prevention of conjunctivitis and pneumonia in the newborn and young infant are reviewed here. Appropriate testing for chlamydial infection in a pediatric victim of sexual assault and the implications of identifying C. trachomatis in suspected cases of childhood sexual abuse also are reviewed.

Study Objective: Evaluation of efficacy and safety of pristinamycin (PRI), compared with amoxicillin (AMX), both at 3 g daily for 7 to 10 days in adults with community-acquired pneumonia (CAP)., Patients and Methods: Multinational, randomized, double blind, double dummy clinical trial of non-inferiority was conducted in 399 patients with a CAP., Results: At inclusion, the mean age was 47.8+/-18.3 years, 24.3% patients were 65 or older. The Fine score was < or =III in 85.4% patients. The bacterial etiology was documented in 34.8% of patients: Streptococcus pneumoniae (48.1%), Mycoplasma pneumoniae (18.6%), Haemophilus influenzae (14.7%), Chlamydia pneumoniae (13.2%), Legionella pneumophila (9.3%). In the clinical per-protocol population, the clinical success rate was 87.6% in each group: 149/170 patients (PRI) and 148/169 (AMX); The 95% confidence interval was [-6.61%; 7.23%]. In modified intend to treat population, the clinical success rate was 79.9% (151/189) in the PRI group and 83.0% (151/182) in the AMX group [CI 95% (-10.87%; 4.69%)]. A satisfactory bacteriological response was observed in 82.3% (51/62) of PRI patients and 88.1% (59/67) of AMX patients. Treatment related adverse events occurred similarly in both groups according to the expected tolerance profile of the two drugs. No serious adverse events in both groups were related to the study drugs., Conclusions: In this study, PRI 3 g daily was clinically as effective and well tolerated as AMX 3 g daily, for 7 to 10 days, in PPc, in the treatment of bacterial community-acquired pneumonia.

This article will critically review the evidence linking pneumonia to the aspiration of microbe-laden oropharyngeal secretions and tie that to the predisposition for these processes to affect dependent, medically compromised individuals. The goal of this review is to alert the reader to the role that oral disease and oral health play in fostering and preventing, respectively, widespread and potentially fatal pulmonary disease among high-risk individuals.

Most cases of community-acquired pneumonia result from infection with predictable common pathogens. However, rare patients develop pneumonia from unusual bacterial species such as Pasteurella multocida, a Gram-negative oral commensal of most dogs and cats. The majority of P. multocida infections involve skin and soft tissue and complicate a bite or scratch. I report the case of an elderly man who owned 16 cats and developed bacteremic pneumonia with P. multocida. .

Principles: Intensive Care Unit Acquired Pneumonia is the most frequent infection among patients receiving mechanical ventilation and has an important impact on patient mortality. Thrombocytopenia is one of the most common laboratory abnormalities in Intensive Care Unit (ICU). The aim of this study was to evaluate the relationship between platelet count and Intensive Care Unit Acquired Pneumonia (ICUAP)., Methods: Medical records of 41 mechanically-ventilated pulmonary ICU patients having at least one ICUAP were reviewed. The date of first ICUAP, etiologic pathogens, platelet count at admission, the nadir value within seven days before and after the date of ICUAP, development of thrombocytopenia (platelet <100 x 10(3)/mm(3)), acute physiology and chronic health evaluation (APACHE) II scores on admission, medications and events that can effect platelet count and other laboratory values were noted., Results: The meantime for the first ICUAP was 13 +/- 10.3 days after ICU admission. The nadir platelet count associated with ICUAP (ICUAPplatelet count) was seen on 12.1 +/- 11.3th day after ICU admission; with a significant fall (30% fall) when compared to admission platelet count (platelet counts are 157.2 +/- 87.4 x 10(3)/mm(3), 224.1 +/- 106.3 x 10(3)/mm(3) respectively, p <0.001). Fifteen of the 41 patients had an episode of thrombocytopenia during their ICU stay and these patients had a higher mortality rate than nonthrombocytopenics (mortality rates are 80% and 50% respectively, p = 0.05)., Conclusion: Besides the proven role of thrombocytopenia in prognosis in ICU, the significant fall in platelet count can be an early warning parameter and possible diagnostic hint for severe infections in ICU such as ICUAP.