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Introduction: The overall reject rate (RR) of our newly set up Radiology department was an average of 14%, higher than the recommended 8% target and 10% threshold set by the American Association of Physicists in Medicine (AAPM). An analysis done to identify potential causes of a high RR suggested that radiographers might have been rejecting images of diagnostic value. A lack of consistency in the definition of a diagnostic value image amongst radiographers may be a possible cause in the higher overall RR. This study aims to investigate potential discrepancies among radiographers in defining a diagnostic radiograph., Methods: An online survey composed of an image bank with a questionnaire was created, participants grade each image as either accepted or rejected. Fleiss Kappa was used to determine the level of agreement between the radiographers in accepting or rejecting the images in the image bank., Results: Twenty radiographers with varying years of experience participated in this study. There was fair agreement amongst the radiographers' judgements, k=.277 (95% CI, .277 to .278), p < .005. Individual kappa for the "Accept" and "Reject" categories were both 0.277. There is no significant difference in the agreement level across the junior (k=.278), intermediate (k=.371) and senior (k=.275) radiographers., Conclusion: The result suggests that there is discrepancy in the radiographers' definition of a diagnostic radiograph and this misalignment of radiographers' perception might be one of the underlying causes of high RR., Implications for Practice: This study has provided the researchers with a better insight on the underlying cause of the department high RR. By calibrating the radiographers' definition of a diagnostic radiograph, it will help realign the radiographer's agreement on when a radiograph should be rejected. This will reduce the overall RR and patient's overall dose. A lower RR translates to a more efficient turnaround time in General Radiography services, ensuring quality service is provided without further strain on our limited resources., (Copyright © 2024. Published by Elsevier Inc.)

Introduction: Tuberculosis (TB) remains endemic in Singapore. Singapore's clinical practice guidelines for the management of tuberculosis were first published in 2016. Since then, there have been major new advances in the clinical management of TB, ranging from diagnostics to new drugs and treatment regimens. The National TB Programme convened a multidisciplinary panel to update guidelines for the clinical management of drug-susceptible TB infection and disease in Singapore, contextualising current evidence for local practice., Method: Following the ADAPTE framework, the panel systematically reviewed, scored and synthesised English-language national and international TB clinical guidelines published from 2016, adapting recommendations for a prioritised list of clinical decisions. For questions related to more recent advances, an additional primary literature review was conducted via a targeted search approach. A 2-round modified Delphi process was implemented to achieve consensus for each recommendation, with a final round of edits after consultation with external stakeholders., Results: Recommendations for 25 clinical questions spanning screening, diagnosis, selection of drug regimen, monitoring and follow-up of TB infection and disease were formulated. The availability of results from recent clinical trials led to the inclusion of shorter treatment regimens for TB infection and disease, as well as consensus positions on the role of newer technologies, such as computer-aided detection-artificial intelligence products for radiological screening of TB disease, next-generation sequencing for drug-susceptibility testing, and video observation of treatment., Conclusion: The panel updated recommendations on the management of drug-susceptible TB infection and disease in Singapore.

Tuberculosis (TB) is a public health challenge globally, and molecular testing is recommended to expedite diagnosis. Concerns that Xpert MTB/RIF assay (Xpert) may be less sensitive when testing paucibacillary samples led to the development of the Xpert MTB/RIF Ultra assay (Ultra). We evaluated the performance of Ultra against Xpert on clinical samples sent to the national reference laboratory in Singapore. In total, 149 samples collected between January 2019 and November 2020 were analysed. Mycobacterium tuberculosis complex (MTBC) was isolated from 55 cultures. Using culture as the reference standard, Ultra demonstrated higher sensitivity (96.4% vs 85.5%) and marginally lower specificity (88.3% vs 89.4%) compared to Xpert in the full cohort. When considering only paucibacillary specimens such as extrapulmonary and smear-negative samples, similar results were obtained. Reclassifying Ultra trace results (low levels of MTB are detected but no rifampicin resistant result is detected) as negative in the full cohort led to a decrease in sensitivity by 10.9% and a marginal increase in specificity by 1.1%. In instances of low bacillary load, Ultra also identified rifampicin resistance more accurately than Xpert, when corroborated against other methods such as broth microdilution, line probe assay and whole genome sequencing (WGS). One isolate tested rifampicin-resistant using Xpert and Ultra, but was phenotypically susceptible and WGS demonstrated the presence of the silent mutation Thr444Thr. Ultra is more sensitive than Xpert in the detection of MTBC and rifampicin resistance in our local setting. Nevertheless, the results of molecular testing should still be correlated with phenotypic studies., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Open Reduction and Internal Fixation (ORIF) with volar locking plates are commonly used to manage distal radial fractures. The anatomical tilt lateral (ATL) wrist X-ray is often required for evaluation of intra-articular screw penetration due to the screw position. This study aims to evaluate the correlation between the tube angulation given by performing radiographers for the ATL projection and the post-examination measurement of radial inclination (RI) on the Posterior Anterior (PA) wrist image., Methods: A retrospective review was performed for 36 patients. A standardised method developed by Kreder et al. (1996) was used to measure the RI on the PA wrist image. All ATL images sent into Picture Archiving and Communications System (PACS) have the tube angulation applied annotated on the image. Pearson's correlation was used to analyse the co-relationship between the RI and the tube angle applied for ATL projection., Results: The average angle of RI measured by the four observers was 19. Normality of 0.385 was established. A positive correlation (p = 0.792) between the RI and the tube angle applied for ATL was found., Conclusion: Our study found a strong positive correlation between the tube angulation applied by performing radiographers for the ATL projection and the post-examination RI measured on the PA wrist image by the independent reviewers. This suggests that radiographers can use the measured RI to apply the tube angulation when performing the ATL wrist X-ray, instead of estimating the tube angulation to be applied., Implications for Practice: Using the measured RI to apply the tube angulation when performing the ATL wrist X-ray will ensure a more reliable and reproducible way that could reduce the number of repeated images and, thus, unnecessary radiation dose to patients., (Copyright © 2023 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe the molecular epidemiology of Mycobacterium tuberculosis complex (MTBC) and factors associated with its transmission in Singapore., Methods: Spoligotyping, 24-loci mycobacterial interspersed repetitive units - variable number of tandem repeats (MIRU-VNTR) typing and demographic data from the national TB notification registry of MTBC culture-positive cases notified from January 2011 to December 2017 were analysed., Results: Of the 12,046 culture-positive cases notified, complete spoligotyping and MIRU-VNTR typing results were available for 8690 (72.1%) belonging to 4950 (57.0%) local-born and 3740 (43.0%) foreign-born persons. From these, 4810 (55.3%) were identified in 883 clusters. The proportion of recent transmission was 45.2%. The East-Asian Lineage 2 accounted for 4045 (47.1%) of isolates, and disproportionately accounted for large clusters. Clustered cases were more likely to be older than 50 years, male, Malay, local-born, Singapore citizens or Permanent Residents, of lower socioeconomic status, imprisoned; to harbour East-Asian Lineage 2 strain; to have cavitary pulmonary TB, positive sputum smear or be recalcitrant treatment defaulters. They were less likely to have multidrug-resistant, or isoniazid or rifampicin mono-resistant TB., Conclusion: We demonstrated the diversity of MTBC strains and, notwithstanding the likely over-estimation of clustering using these genotyping methods, elucidated factors associated with TB transmission in Singapore., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Introduction: The current technique of angulating for a skyline knee projection relies heavily on the radiographer's estimation of the patella tilt, rendering it subjective and prone to errors. This study therefore aims to (i) examine the correlation between angle ABC measured on the lateral X-ray image and skyline angulation (measured in degrees) and (ii) determine the inter-rater reliability of angle ABC measurements., Methods: 145 sets of lateral and skyline X-ray images from patients aged 40-70 years old were retrospectively analysed. Angle ABC was measured using prominent landmarks such as the trochlear sulcus, tibial tuberosity and the anterior border of the patella on the lateral knee radiograph. It was then retrospectively compared with the skyline tube angulations to identify any correlation between the two. An inter-rater reliability test was also conducted using the intraclass correlation coefficient (ICC) to determine the reproducibility of the measurement method., Results: A weak correlation was found between angle ABC and skyline angulation (r = 0.1, p = 0.25). The proposed method of measurement shows good inter-rater reliability (ICC = 0.81, 95% CI: 0.77 to 0.84)., Conclusion: There is insufficient evidence to indicate a correlation between angle ABC and skyline angulation. However, angle ABC can be reliably measured, implying the replicability of the measurement method for other purposes., Implications for Practice: The proposed measurement method of angle ABC on the lateral view could have future applications in other areas such as in the measurement of patellofemoral alignment and trochlear morphology., Competing Interests: Conflict of interest statement None., (Copyright © 2021 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Introduction: A chest X-ray (CXR), taken in full inspiration, is important to ensure pathology in the lungs will not be missed. To achieve this, effective communication on breathing instructions for patients is crucial. During the COVID-19 pandemic, radiographers in Sengkang General Hospital (SKH) were challenged when performing CXR for the patients whose native language is not English. Most of these patients were foreign workers living in the same dormitory which had formed the largest COVID-19 cluster in Singapore. These dormitory residents found it difficult to understand and adhere to breathing instructions, resulting in a suboptimal degree of inspiration when the CXRs were taken. This may ultimately affect the diagnostic value of the radiographs. This paper aims to share and evaluate how radiographers tackled this issue and continued to acquire fully-inspired CXR for the dormitory residents despite the language barrier., Methods: Using a combination of online survey and retrospective analysis of the rejection rates of CXR done over the period of early April to early June, a team of radiographers evaluated the effectiveness of using audio recordings in managing the issue of not achieving a fully inspired CXR for patients due to language barrier., Results: The rejection rate for CXR due to suboptimal inspiration decreased from 26% to 9% upon implementation of the audio recordings. 92.3% of the CXRs taken within this period also fulfilled the criteria of a fully-inspired CXR, as evidenced by having at least 9 posterior ribs seen above the right hemi-diaphragm. Survey results found a fairly balanced number of radiographers who agreed and disagreed that a fully-inspired CXR was achieved for most of their patients after utilisation of translation manuals and audio recordings., Conclusion: After the implementation of audio recordings, the decrease in rejection rate of CXR and an audit which demonstrated that CXR quality was upheld had proven that the radiographers successfully achieved fully-inspired CXR for suspected COVID-19 patients. This confirmed that using pre-recorded audio instructions was an efficient intervention albeit being a one-way communication, leads to more accurate imaging results, aligning with existing literature on communication experiences between radiographers and patients. Moreover, the decreased rejection rate of CXRs had increased department efficiency consequently reducing departmental expenses in the long run., Implications of Practice: Given that we have an ageing population and the vast majority of the elderly converse in their various dialects, positive feedback from radiographers presented opportunities to expand the translation manual and audio recordings to include local dialects. These can be seamlessly integrated in CXR and other procedures in the hospital setting. To ensure that the translations are culturally sensitive, attention should be paid to the translation process of instructions into other languages and local dialects by enlisting the help of native speakers., Competing Interests: Conflict of interest statement None., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Previously treated (ie, recurrent) tuberculosis (TB) cases account for approximately 7%-8% of incident TB globally and in Singapore. Molecular fingerprinting has enabled the differentiation of these patients into relapsed or reinfection cases., Methods: Patient demographics, disease characteristics, and treatment information were obtained from the national TB notification registry and TB Control Unit. We performed a retrospective, case-control study to evaluate factors associated with recurrent TB disease in Singapore citizens and permanent residents with culture-positive TB from 2006 to 2013 and who developed a second episode of culture-positive TB up to 2016 using multivariable logistic regression analyses., Results: Ninety-one cases with culture-positive first and recurrent TB disease episodes were identified. Recurrent TB was associated with age ≥60 years (adjusted odds ratio [aOR], 1.98 [95% confidence interval {CI}, 1.09-3.61), male sex (aOR, 2.29 [95% CI, 1.22-4.51]), having concomitant pulmonary and extrapulmonary TB (aOR, 3.10 [95% CI, 1.59-6.10]) and extrapulmonary TB alone (aOR, 3.82 [95% CI, 1.12-13.31]), and was less likely in non-Malays (aOR, 0.52 [95% CI, .27-.99]). DNA fingerprinting results for both episodes in 49 cases differentiated these into 28 relapsed and 21 reinfection cases. Relapse was associated with having concomitant pulmonary and extrapulmonary TB (aOR, 9.24 [95% CI, 2.50-42.42]) and positive sputum acid-fast bacilli smear (aOR, 3.95 [95% CI, 1.36-13.10])., Conclusions: Relapse and reinfection contributed to 57% and 43%, respectively, of recurrent TB in Singapore. Our study highlights the underappreciated association of concomitant pulmonary and extrapulmonary TB as a significant risk factor for disease relapse., (© The Author(s) 2021. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

There were 290 multidrug-resistant (MDR)-TB cases diagnosed in Singapore from 2006 to 2018. Eighty-one percent were foreign-born. Spoligotyping and MIRU-VNTR methods identified 108 patients in 24 clusters. The Beijing spoligotype accounted for 22 clusters. Whole genome sequencing (WGS) analysis reduced the number of clustered patients and clusters to 43 and nine respectively. One MIRU cluster was redefined into three WGS clusters. All the clusters had foreign-born source cases. Forty percent of local-born, versus 9% of foreign-born, MDR-TB cases belonged to WGS clusters. WGS more accurately elucidated potential MDR-TB transmission which was overestimated by conventional genotyping methods in Singapore.

Introduction: With the current Covid-19 pandemic, general wards have been converted into cohort wards for Covid-19 patients who are stable and ambulant. A 2-radiographer mobile radiography team is required to perform bedside Chest X-rays (CXR) for these patients. Hospital guidelines require both radiographers to be in full Personal Protective Equipment (PPE) throughout the image acquisition process and the mobile radiographic unit needs to be disinfected twice after each case. This affects the efficiency of the procedure and an increase usage of limited PPE resources. This study aims to explore the feasibility of performing mobile chest radiography with the mobile radiographic unit in a "clean" zone of the hospital ward., Methods: An anthropomorphic body phantom was used during the test. With the mobile radiographic unit placed in a "clean" zone, the phantom and the mobile radiographic unit was segregated by the room door with a clear glass panel. The test was carried out with the room door open and closed. Integrated radiation level and patient dose were measured. A consultant radiologist was invited to review and score all the images acquired using a Barco Medical Grade workstation. The Absolute Visual Grading Analysis (VGA) scoring system was used to score these images., Results: A VGA score of 4 was given to all the 40 test images, suggesting that there is no significant differences in the image quality of the images acquired using the 2 different methods. Radiation exposure received by the patient at the highest kV setting through the glass is comparable to the regular CXR on patient without glass panel at 90 kV, suggesting that there is no significant increase in patient dose., Conclusion: The result suggests that acquiring CXR with the X-ray beam attenuating through a glass panel is a safe and feasible way of performing CXR for COVID-19 patients in the newly converted COVID wards. This will allow the mobile radiographic unit as well as one radiographer to be completely segregated from the patient., Implications for Practice: This new method of acquiring CXR in an isolation facility set up requires a 2-Radiographer mobile radiography team, and is applicable only for patients who are generally well and not presented with any mobility issues. It is also important to note that a clear glass panel must be present in the barriers set up for segregation between the "clean" zone and patient zone in order to use this new method of acquiring CXR., (Copyright © 2020 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Introduction: The value of combined blended and experiential learning on radiographer diagnostic comment has not been explored. This study aims to examine the accuracy of image interpretation comment of radiographers who received a period of blended and experiential learning in Radiographer Abnormality Detection Systems (RADS)., Methods: We evaluated the diagnostic opinions of 13 radiographers who received a blended training and experiential learning (a process of self-learning and reflection) in RADS. Radiographers' opinions on 16,483 images were examined using the final radiologists' report as a reference standard. For each radiographer, we recorded the number of true positive, true negative, false positive and false negative opinions and MedCal® was used to calculate diagnostic performance and error rates. A t-test was used to assess whether the number of images read was associated with performance and whether the radiographers retained performance over time., Results: Sensitivity ranged from 87.4 (84.0-90.2) to 98.9 (97.5-99.7) with a mean of 94.3 (93.6-94.8). Specificity varied from 96.4 (94.8-97.5) to 99.9 (99.41-100.0) with a mean of 98.2 (97.9-98.4). Diagnostic accuracy ranged from 93.1 (91.5-94.4) to 99.5 (98.9-99.8) with a mean of 96.9 (96.6-97.1). The mean false positive rate was 0.018 (range: 0.010-0.031) with a false negative rate of 0.057 (range: 0.026-0.11). There were no differences in performance between the first and latter nine months of providing opinions and the number of images reviewed was not associated with performance., Conclusion: Radiographers who received blended and experiential learning in RADS provide accurate diagnostic comments on plain emergency appendicular skeleton radiographs., Implication for Practice: A combined blended and experiential learning can equip radiographers to provide diagnostic opinion on plain appendicular skeleton radiographs., (Copyright © 2020 The College of Radiographers. All rights reserved.)

Introduction: The COVID-19 pandemic resulted in the suspension of clinical training for undergraduate radiography students in Singapore. Coordinated preparation plans and strategies between the university and hospitals were needed to safely resume clinical placements within national and hospitals' risk control measures against COVID-19 transmission., Methods: Singapore Institute of Technology (SIT) and the Radiology Department of Singapore General Hospital (SGH) had collaborated to meet requirements for safe resumption of clinical placements. SIT prepared students by emphasising compliance to all risk measures, addressing concerns of risk transmission, meeting learning objectives, and reassessing infection control competencies. In tandem, SGH prepared an orientation programme and used technology for open communication among faculty, clinical educators and students which included monitoring of well-being and rapid dissemination of updates. Of note, SGH reorganised operating procedures and physical spaces to meet national standards of safe physical distancing, restricted movement between treatment areas and teams, and rosters to remain committed to the supervision and education of students., Results: Clinical placements resumed 3 months following suspension. Clinical educators faced the challenge of the need for balance between increasing clinical load and student supervision. A solution was frequent engagement and support by faculty, with educators and students via video conferencing platforms. Students' well-being was frequently checked. There was less variation in cases which simulation training made up for some of the learning objectives., Conclusion: Adaptation and commitment to continue active and quality clinical education while ensuring students' safety were vital during a pandemic. Clinical training within stringent precautionary measures may shape the era of the new norm., (Copyright © 2020. Published by Elsevier Inc.)

Background: Disseminated Bacillus Calmette-Guérin (BCG) disease (BCGosis) is a classical feature of children with primary immunodeficiency disorders (PIDs)., Methods: A 15-year retrospective review was conducted in KK Women's and Children's Hospital in Singapore, from January 2003 to October 2017., Results: Ten patients were identified, the majority male (60.0%). The median age at presentation of symptoms of BCG infections was 3.8 (0.8 - 7.4) months. All the patients had likely underlying PIDS - four with Severe Combined Immunodeficiency (SCID), three with Mendelian Susceptibility to Mycobacterial Diseases (MSMD), one with Anhidrotic Ectodermal Dysplasia with Primary Immunodeficiency (EDA-ID), one with combined immunodeficiency (CID), and one with STAT-1 gain-of-function mutation. Definitive BCGosis was confirmed in all patients by the identification of Mycobacterium bovis subsp BCG from microbiological cultures. The susceptibility profiles of Mycobacterium bovis subsp BCG are as follows: Rifampicin (88.9%), Isoniazid (44.47%), Ethambutol (100.0%), Streptomycin (100.0%), Kanamycin (100.0%), Ethionamide (25.0%), and Ofloxacin (100.0%). Four patients (40.0%) received a three-drug regimen. Five patients (50.0%) underwent hematopoietic stem cell transplant (HSCT), of which three (60%) have recovered. Overall mortality was 50.0%., Conclusion: Disseminated BCG disease (BCGosis) should prompt immunology evaluation to determine the diagnosis of the immune defect. A three-drug regimen is adequate for treatment if the patient undergoes early HSCT., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Heater-cooler units (HCUs) have been implicated in the recent global outbreak of invasive Mycobacterium chimaera infection among patients following cardiothoracic surgery. Because infected patients tend to remain asymptomatic for extended periods, detection of M. chimaera from HCUs in real time is essential to halting the ongoing M. chimaera HCU-associated outbreak. Sample collection protocols to evaluate the presence of M. chimaera offer conflicting recommendations regarding the addition of sodium thiosulfate (NaT) during the collection process., Aim: To study the effect of NaT on M. chimaera recovery and culture contamination., Methods: Seventy-six paired HCU water samples (with and without NaT) were collected, processed and cultured simultaneously into Lowenstein-Jensen slants, Middlebrook 7H10 agar plates, and mycobacterial growth indicator tubes (MGITs), and incubated at 37°C. A subset of 31 paired samples was additionally cultured on MGITs and incubated at 30°C., Findings: Of 76 samples incubated at 37°C in each of the three media, with and without NaT, M. chimaera was identified in at least one aliquot of 21 samples., Conclusion: The presence of NaT did not significantly increase the probability of recovering M. chimaera in a multi-variable conditional logistic model and culture contamination rates were similar between aliquots with and without NaT. In the subset of samples cultured on MGITs at both 30°C and 37°C, the presence of NaT again was not associated with M. chimaera recovery, but was significantly associated with reduced culture contamination., (Copyright © 2020 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

Background: Unfamiliarity with the presentation, diagnostic process, and treatment of cutaneous non-tuberculous mycobacterium (NTM) infection leads to poorer outcomes. We describe our experience with managing cutaneous NTM infection in a regional hospital in Singapore from 2005 to 2014., Methods: Adult patients with cutaneous NTM infections were identified through positive skin tissue cultures in this retrospective case series. We excluded patients younger than 21 years of age, patients whose care was transferred to another hospital, and patients with catheter-related infections. Data including demographic variables, as well as disease and treatment outcomes, were collected. We compared the data between patients with and without risk factors for immunosuppression to look for any significant difference., Results: Fifty-eight cases were reviewed. Mycobacterium abscessus was the commonest organism isolated (51.7%), and abscesses or inflamed cysts were the most common presentation. Nineteen specimens (57.6%) showed suppurative or necrotizing granulomatous dermatitis on biopsy and acid-fast bacilli were identified in 2 of 21 histologic specimens (9.5%) stained for mycobacterium. Treatment included systemic antibiotics, surgery, or both. In total, 33 cases had clinical resolution while 25 cases were lost to follow-up. Our study was limited by the under-reporting of cases, bias due to data from a single center, and high dropout rates, thereby precluding a detailed assessment of treatment outcomes., Conclusions: A high index of suspicion is required to diagnose cutaneous NTM infection. Education of both patients and physicians will help to raise the level of awareness and reduce treatment delays., (© 2018 The International Society of Dermatology.)

Background: Information on non-tuberculosis mycobacterial (NTM) diseases remains limited in Singapore and other Southeast Asian countries. This study aimed to delineate epidemiological and clinical features of pulmonary NTM disease., Methods: A retrospective review was performed on all NTM isolates identified in Singapore General Hospital from 2012 to 2016 using the 2007 ATS/IDSA diagnostic criteria., Results: A total of 2026 NTM isolates from 852 patients were identified. M. abscessus-chelonae group (1010, 49.9%) was the most commonly isolated and implicated in pulmonary NTM disease. Pulmonary cases (352, 76%) had the highest prevalence among patients diagnosed with NTM diseases (465/852, 54.6%) with no gender difference. Male patients were older (68.5 years, P = 0.014) with a higher incidence of chronic obstructive pulmonary disease (COPD) (23.6%, P < 0.001) and recurrent cough with phlegm production (51.6%, P = 0.035). In contrast, more female patients had bronchiectasis (50%, P < 0.001) and haemoptysis (37.6%, P = 0.042). Age and COPD were associated with multiple NTM species isolation per patient., Conclusions: M. abscessus-chelonae group was the commonest NTM species isolated in Singapore. Pulmonary NTM infection has the highest frequency with male and female patients associated with a higher incidence of COPD and bronchiectasis respectively. Age and COPD were associated with multiple NTM species isolation per patient.

Introduction: Leprosy is rarely reported in developed countries with low-prevalence settings. Its diagnosis may be missed due to its low frequency in non-endemic regions, as well as its long incubation period. The report describes an imported leprosy case of a healthcare worker in Singapore., Case Presentation: A Filipino nursing personnel presented with a persistent non-tender erythematous plaque over his right upper back for many years despite topical treatment. He had the lesion before coming to Singapore but decided to seek medical consultation only after the lesion progressed with new erythematous papules developing over his face, trunk and upper limbs. Punch biopsies of skin lesions revealed fite-positive bacilli, which were identified to be Mycobacterium leprae by GenoType LepraeDR v1 assay (Hain LifeScience, Germany). No mutation was detected at rpoB (rifampicin), gyrA (ofloxacin) and folP1 (dapsone) gene targets. He was started on multi-drug therapy and responded to the treatment. The only prolonged close contact he had was his housemate who was screened and given a single dose of rifampicin as chemoprophylaxis., Conclusion: In non-endemic settings, awareness is crucial in diagnosing leprosy. The availability of molecular testing and multi-disciplinary management are essential in the confirmation and control of this disease of public health importance., Competing Interests: The authors declare that there are no conflicts of interest., (© 2019 The Authors.)

Accurate and reliable drug susceptibility testing (DST) is essential for the effective treatment and control of tuberculosis. With the increase in drug-resistant organisms, newer and less conventional antimicrobial agents are used for treatment. Recently, we found an unprecedented rise in the number of clofazimine-resistant Mycobacterium tuberculosis isolates in our laboratory. An investigation found that this phenomenon was due to a change in the method of drug preparation. We performed studies to assess the impact of water and dimethyl sulfoxide (DMSO) as a final diluent for clofazimine drug testing. Based on our findings, the use of DMSO as a solvent for M. tuberculosis DST was optimised using the BACTEC MGIT 960 platform., (Copyright © 2018 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Objective: Between February 2012 and May 2016, six residents of an 11-storey apartment block were diagnosed with MDR-TB. Based on initial tests, all isolates had similar genotypic profiles, although there were no identifiable epidemiological transmission patterns between three cases. We present findings from the cluster investigation and results of a mass screening exercise., Design: Free voluntary TB screening was offered to past and current residents of the apartment block, comprising an interview, Chest X-Ray, and Interferon Gamma Release Assay or Tuberculin skin test. Expected latent TB proportions were calculated using a reference population, and whole genome sequencing (WGS) was performed., Results: The index case was involved in a separate gaming centre outbreak involving five patrons. 241 current (67.9% of 355 residents) and 18 past residents were screened. The latent TB proportion was 19.9%, which was at the higher end of the expected range. WGS confirmed relatedness of cases' MDR-TB isolates- eight of 10 isolates were genetically identical, while the remaining two were one Single Nucleotide Polymorphism apart., Conclusion: With WGS, TB clusters not apparent through regular activity-based contact tracing may be detected. Mass screening may help inform the extent of transmission, but is limited by participation and difficulties in interpretation., (Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Diagnostic and treatment delays increase the severity and transmission of pulmonary tuberculosis (PTB). This study aimed to evaluate TB diagnostic and treatment delays in acid-fast bacilli (AFB) smear-negative patients., Methods: This was a retrospective observational study. Patients with positive AFB culture of Mycobacterium tuberculosis complex (MTC) were selected from among hospitalised patients with a diagnosis of pneumonia. Admission ward, anti-tuberculosis treatment and the duration of AFB culture were compared between smear-positive and smear-negative patients., Results: Of the 70 patients with positive isolation of MTC in AFB culture, 27 (38.5%) were smear-negative; of these, 18 (66.7%) were not isolated while in hospital, and 17 (63%) were neither diagnosed nor treated for TB. In contrast, 41 of the 43 smear-positive patients (95.3%) were directly admitted or quickly transferred to the isolation room and started on anti-tuberculosis treatment (P < 0.001). Samples from smear-negative patients required more time to grow MTC in AFB culture than those of smear-positive patients (23 days vs. 14 days, P < 0.001). Diabetes was significantly associated with AFB smear positivity, with an odds ratio of 12.2., Conclusions: Negative AFB smears caused significant diagnostic and treatment delay. Patients staying in the general ward were exposed to TB patients who were not diagnosed in time.

Background: Nontuberculous mycobacterium (NTM) infections are rare in children, with limited published studies. The course of the disease can be variable and there are no accepted treatment guidelines for the management of NTM infections in children., Objective: To review a cohort of pediatric patients admitted to a tertiary pediatric hospital in Singapore for cutaneous NTM infections., Methods: A retrospective review was performed of all children admitted to KK Women's and Children's Hospital with cutaneous NTM infections from 2002 to 2012., Results: Sixty-seven patients with positive NTM cultures from various body sites were identified. Eight of the 67 patients (11.9%) presented with cutaneous NTM without evidence of systemic involvement. The mean age at diagnosis for these eight patients was 10 years (range 5-21 yrs). Mycobacterium abscessus was the most common NTM isolated (five patients), followed by Mycobacterium hemophilium (two patients) and Mycobacterium kansasii (one patient). Most patients presented with isolated skin abscesses. Two patients were immunocompromised. Six patients required multidrug antibiotic treatment for a median duration of 5.5 months (range 3-17 mos). The median follow-up duration was 8.5 months (range 2 wks-29 mos)., Conclusion: Although the incidence of cutaneous NTM is rare, the diagnosis should be considered in patients presenting with chronic wounds. Most patients require treatment with multidrug antibiotic therapy, although uncomplicated abscesses can be treated with surgical incision and drainage alone., (© 2015 Wiley Periodicals, Inc.)

Mycobacterium tuberculosis strains of the Beijing lineage are globally distributed and are associated with the massive spread of multidrug-resistant (MDR) tuberculosis in Eurasia. Here we reconstructed the biogeographical structure and evolutionary history of this lineage by genetic analysis of 4,987 isolates from 99 countries and whole-genome sequencing of 110 representative isolates. We show that this lineage initially originated in the Far East, from where it radiated worldwide in several waves. We detected successive increases in population size for this pathogen over the last 200 years, practically coinciding with the Industrial Revolution, the First World War and HIV epidemics. Two MDR clones of this lineage started to spread throughout central Asia and Russia concomitantly with the collapse of the public health system in the former Soviet Union. Mutations identified in genes putatively under positive selection and associated with virulence might have favored the expansion of the most successful branches of the lineage.

Nontuberculous mycobacteria infection is a growing global concern, but data from Asia are limited. This study aimed to describe the distribution and antibiotic susceptibility profiles of rapidly growing mycobacterium (RGM) isolates in Singapore. Clinical RGM isolates with antibiotic susceptibility tests performed between 2006 and 2011 were identified using microbiology laboratory databases and minimum inhibitory concentrations of amikacin, cefoxitin, clarithromycin, ciprofloxacin, doxycycline, imipenem, linezolid, moxifloxacin, sulfamethoxazole or trimethoprim-sulfamethoxazole, tigecycline and tobramycin were recorded. Regression analysis was performed to detect changes in antibiotic susceptibility patterns over time. A total of 427 isolates were included. Of these, 277 (65%) were from respiratory specimens, 42 (10%) were related to skin and soft tissue infections and 36 (8%) were recovered from blood specimens. The two most common species identified were Mycobacterium abscessus (73%) and Mycobacterium fortuitum group (22%), with amikacin and clarithromycin being most active against the former, and quinolones and trimethoprim-sulfamethoxazole against the latter. Decreases in susceptibility of M. abscessus to linezolid by 8.8% per year (p 0.001), M. fortuitum group to imipenem by 9.5% per year (p 0.023) and clarithromycin by 4.7% per year (p 0.033) were observed. M. abscessus in respiratory specimens is the most common RGM identified in Singapore. Antibiotic options for treatment of RGM infections are increasingly limited., (Copyright © 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Mycobacterium tuberculosis Beijing strains represent targets of special importance for molecular surveillance of tuberculosis (TB), especially because they are associated with spread of multidrug resistance in some world regions. Standard 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing lacks resolution power for accurately discriminating closely related clones that often compose Beijing strain populations. Therefore, we evaluated a set of 7 additional, hypervariable MIRU-VNTR loci for better resolution and tracing of such strains, using a collection of 535 Beijing isolates from six world regions where these strains are known to be prevalent. The typeability and interlaboratory reproducibility of these hypervariable loci were lower than those of the 24 standard loci. Three loci (2163a, 3155, and 3336) were excluded because of their redundant variability and/or more frequent noninterpretable results compared to the 4 other markers. The use of the remaining 4-locus set (1982, 3232, 3820, and 4120) increased the number of types by 52% (from 223 to 340) and reduced the clustering rate from 58.3 to 36.6%, when combined with the use of the standard 24-locus set. Known major clonal complexes/24-locus-based clusters were all subdivided, although the degree of subdivision varied depending on the complex. Only five single-locus variations were detected among the hypervariable loci of an additional panel of 92 isolates, representing 15 years of clonal spread of a single Beijing strain in a geographically restricted setting. On this calibrated basis, we propose this 4-locus set as a consensus for subtyping Beijing clonal complexes and clusters, after standard typing.

Background: Tuberculosis remains common in Singapore, increasing in incidence since 2008. We attempted to determine the molecular epidemiology of Mycobacterium tuberculosis complex (MTC) isolates locally, identifying major circulating genotypes and obtaining a glimpse of transmission dynamics., Methodology: Non-duplicate MTC isolates archived between 2006 and 2012 at the larger clinical tuberculosis laboratory in Singapore were sampled for spoligotyping and MIRU-VNTR typing, with case data obtained from the Singapore Tuberculosis Elimination Program registry database. Isolates between 2008 and 2012 were selected because of either multidrug-resistance or potential epidemiological linkage, whereas earlier isolates were randomly selected. Separate analyses were performed for the early (2006-2007) and later (2008-2012) study phases in view of potential selection bias., Principal Findings: A total of 1,612 MTC isolates were typed, constituting 13.1% of all culture-positive tuberculosis cases during this period. Multidrug-resistance was present in 91 (5.6%) isolates - higher than the national prevalence in view of selection bias. The majority of isolates belonged to the Beijing (45.8%) and EAI (22.8%) lineages. There were 347 (30.7%) and 133 (27.5%) cases clustered by combined spoligotyping and MIRU-VNTR typing from the earlier and later phases respectively. Patients within these clusters tended to be of Chinese ethnicity, Singapore resident, and have isolates belonging to the Beijing lineage. A review of prior contact investigation results for all patients with clustered isolates failed to reveal epidemiological links for the majority, suggesting either unknown transmission networks or inadequate specificity of the molecular typing methods in a country with a moderate incidence of tuberculosis., Conclusion: Our work demonstrates that Singapore has a large and heterogeneous distribution of MTC strains, and with possible cross-transmission over the past few years based on our molecular typing results. A universal MTC typing program coupled with enhanced contact investigations may be useful in further understanding the transmission dynamics of tuberculosis locally.

We describe three zoonotic streptococcal soft tissue infections resulting from fresh seafood contact. One was a localized thumb infection with Streptococcus iniae in an immunocompetent healthy young male resulting from a puncture wound from a crab pincer. The other two were cases of ascending upper limb cellulitis associated with bacteraemia in mastectomy patients. One of these infections was caused by S. iniae while the other was caused by Streptococcus dysgalactiae subsp. dysgalactiae, a species that has not been previously described as a cause of zoonotic infection. Hence when cleaning raw seafood, protective equipment should be used to minimize the risk of percutaneous injuries.

The Mycobacteria Growth Indicator Tube (MGIT 960) system was evaluated against Lowenstein-Jensen (LJ) medium and the BACTEC 460 TB system for the recovery of mycobacteria from 1393 consecutive urine specimens. The MGIT had a sensitivity of 91.3% [95% confidence interval (CI), 83.2-99.4] when the combination of BACTEC 460 and LJ medium was used as the reference method. The mean time for positivity for MGIT and BACTEC 460 was 19.3 days and 20 days, respectively, while that for LJ medium was 35 days.The incidence of contamination was highest for LJ medium (n=148), followed by MGIT 960 (n=81), and BACTEC 460 had the lowest incidence of contamination (n=50). In conclusion, the isolation of mycobacteria from urine specimens by the MGIT 960 is comparable to that of the BACTEC 460 TB system and solid media.

We reevaluated the BACTEC MGIT 960 antimicrobial susceptibility testing system (MGIT 960 AST) by using 1,112 isolates of Mycobacterium tuberculosis. When the results of MGIT 960 AST were compared with that of the proportion method using Ogawa medium (Ogawa PM), discrepant results were obtained for 30 strains with isoniazid, all resistant by MGIT 960 AST but susceptible by Ogawa PM. For 93% of the strains that produced discrepant results, the MIC was 0.4 or 0.8 microg/ml, showing resistance by the proportion method using Middlebrook agar plates. Furthermore, it was also established by analyses of the katG and inhA genes that strains resistant only by MGIT 960 AST have a low level of isoniazid (INH) resistance, indicating that MGIT 960 AST is a reliable method. Ninety-six strains were resistant to 0.1 microg/ml INH by MGIT 960 AST. When they were divided into three groups, Low-S (susceptible at 0.2 microg/ml), Low-R (resistant at 0.2 microg/ml), and High-R (resistant at 1.0 microg/ml), by Ogawa PM, 43.3% of the Low-S strains had mutations in the promoter region of inhA and no mutations were detected in katG codon 315, while 61.7% of the High-R strains had katG codon 315 mutations or a gross deletion of katG. These results suggest that mutations in inhA are associated with low-level resistance to INH and katG codon 315 mutations are associated with high-level resistance to INH. In addition, the analyses demonstrated some relationship of mutations in the inhA gene with ethionamide resistance for the Low-S strains, but not for the High-R strains.

Objective: To compare the incidence of carbapenemase genes in Acinetobacter baumannii between two time periods., Methods: We studied 114 isolates of imipenem-resistant A. baumannii collected over two 5 month periods (in 1996 and 2001). Isolates showing carbapenemase activity by plate bioassay were screened for carbapenemase genes using PCR. Chromosomal DNA from strains carrying carbapenemase genes was subjected to PFGE after digestion with ApaI., Results: The incidence of imipenem-resistant A. baumannii in our hospital rose from 1.1 per 1000 admissions in 1996 to 2.3 per 1000 admissions in 2001. However, the number of carbapenemase-producing A. baumannii rose only slightly in 2001 (0.8 per 1000 admissions) compared to 1996 (0.5 per 1000 admissions). Of 44 isolates with carbapenemase activity, 4 isolates carried bla(IMP-4), 5 carried bla(OXA-58), and 40 carried bla(OXA-23). In addition, most isolates carried a bla(OXA-51)-type beta-lactamase gene. All strains with bla(IMP-4), also carried bla(OXA-58) and bla(PSE-1), but not bla(OXA-51)-type beta-lactamase genes. PCR analysis repeated on seven recent isolates of susceptible A. baumannii showed only the presence of bla(OXA-51)-type beta-lactamase genes. A total of five novel bla(OXA-51)-type beta-lactamase genes (bla(OXA-88),-91,-93,-94, and -95) and one new bla(OXA-58)-type beta-lactamase gene (bla(OXA-96)) were found., Conclusions: The incidence of carbapenemase genes did not vary significantly between the two study periods. There is a wide diversity of OXA genes in A. baumannii in Singapore. The most common carbapenemase gene found in our study was bla(OXA-23).

We report the first outbreak of vancomycin-resistant Enterococcus faecium colonization and infection among inpatients in the hematology ward of an acute tertiary care public hospital in Singapore. Two cases of bacteremia and 4 cases of gastrointestinal carriage were uncovered before implementation of strict infection control measures resulted in control of the outbreak.

Introduction: The accuracy and practicality of PCR-restriction endonuclease analysis (PRA) for rapid identification of pathogenic rapidly growing mycobacteria (RGM) isolates were evaluated., Materials and Method: PRA identification using an amplified 439-bp segment (amplicon) of the 65-kDa heat shock protein gene was compared to identification by conventional methods, for 39 clinically significant RGM isolates., Results: The accuracy of PRA in the identification of RGM isolates was comparable to that of conventional methods. Moreover, PRA was able to identify RGM faster, within 2 to 3 working days compared to conventional methods which require 2 to 4 weeks to perform and complete different tests., Conclusion: PRA methodology could be easily incorporated into the clinical laboratory setting. This would be beneficial for the management of patients with infections due to pathogenic RGM.

Thirty-six isolates of carbapenem-resistant Pseudomonas aeruginosa were studied. Pulsed-field gel electrophoresis revealed the presence of two clones. One clone carried a bla(IMP-1) gene identical to that first described in Japan. The other clone carried a bla(IMP-1) variant containing four silent mutations. One isolate with a unique pulsed-field gel electrophoresis pattern contained bla(IMP-7).