Review of the role of gastrointestinal multiplex polymerase chain reaction in the management of diarrheal illness.

Acute and chronic diarrheal illness secondary to gastrointestinal infection is a significant cause of morbidity and mortality around the world. A cornerstone of management includes prompt diagnosis and appropriate treatment of culprit pathogens. Timely diagnosis can improve patient care, assist in infection control, and prevent disease outbreaks. Historical methods of diagnosis include traditional culture methods and stool analysis. These are limited by long turnaround time and inability to simultaneously assess multiple pathogens. The advent of multiplexed nucleic acid amplification tests first began with the Food and Drug Administration-approved respiratory virus multiplex polymerase chain reaction (PCR) panel in 2009, followed by gastrointestinal infections in 2013, and neurological infections in 2014. We conducted a review of current literature pertaining to the clinical utility of a gastrointestinal multiplex PCR in management of acute and chronic diarrhea in patients. To date, seven platforms approved by the US Food and Drug Administration are used in detection of various bacterial, viral, and parasitic causative organisms for diagnosis of gastrointestinal infections. The sensitivity and specificity of each assay vary depending on the tested organism. Interpretation of a positive result has to be tailored to the clinical context. Further studies are required to establish the utility of gastrointestinal multiplex PCR from a cost-based perspective, whether specific enteropathogens such as Clostridioides difficile are better assessed with toxin gene detection and whether new parameters such as cycle threshold values can improve clinical application of test results.

Neurology of the H1N1 pandemic in Singapore: a nationwide case series of children and adults.

Neurologic complications have long been associated with influenza. A novel strain of influenza A (H1N1) first described in humans to have outbreak potential in 2009 in Mexico went on to become the first influenza pandemic of this century. We evaluated the neurologic complications of the novel influenza A (H1N1) 2009 in children and adults admitted to all public hospitals in Singapore during the influenza A (H1N1) 2009 pandemic between May 2009 and March 2010. All patients were positive for novel H1N1 infection and presented with neurologic symptoms prior to oseltamivir treatment. Ninety-eight patients (median age 6.6 years, range 0.4-62.6) were identified; 90 % were younger than 18 years; 32 % suffered from preexisting neurological, respiratory, or cardiac disease; and 66 % presented with seizures. Of those presenting with seizures, new onset seizures were the most common manifestation (n = 40, 61.5 %), followed by breakthrough seizures (n = 18, 27.7 %) and status epilepticus (n = 7, 10.8 %). Influenza-associated encephalopathy occurred in 20 %. The majority of children (n = 88) presented with seizures (n = 63, 71.6 %), encephalopathy (n = 19, 21.6 %), and syncope (n = 4, 4.5 %). Among adults, a wider range of neurological conditions were seen, with half of them presenting with an exacerbation of their underlying neurological disease. The neurological symptoms developed at a median of 2 days after the onset of systemic symptoms. The median length of hospital stay was 3 days, and 79 % were monitored in general wards. Neurologic complications associated with the novel influenza A (H1N1) 2009 strain were generally mild and had a good outcome. They occurred more frequently in patients with underlying neurological disorders. Seizures and encephalopathy were the most common manifestations, similar to other influenza virus strains.

A prediction tool for nosocomial multi-drug Resistant Gram-Negative Bacilli infections in critically ill patients - prospective observational study.

BACKGROUND: The widespread use of empiric broad spectrum antibiotics has contributed to the global increase of Resistant Gram-Negative Bacilli (RGNB) infections in intensive care units (ICU). The aim of this study was to develop a tool to predict nosocomial RGNB infections among ICU patients for targeted therapy. METHODS: We conducted a prospective observational study from August'07 to December'11. All adult patients who were admitted and stayed for more than 24 hours at the medical and surgical ICU's were included. All patients who developed nosocomial RGNB infections 48 hours after ICU admission were identified. A prediction score was formulated by using independent risk factors obtained from logistic regression analysis. This was prospectively validated with a subsequent cohort of patients admitted to the ICUs during the following time period of January-September 2012. RESULTS: Seventy-six patients with nosocomial RGNB Infection (31bacteremia) were compared with 1398 patients with Systemic Inflammatory Response Syndrome (SIRS) without any gram negative bacterial infection/colonization admitted to the ICUs during the study period. The following independent risk factors were obtained by a multivariable logistic regression analysis - prior isolation of Gram negative organism (coeff: 1.1, 95% CI 0.5-1.7); Surgery during current admission (coeff: 0.69, 95% CI 0.2-1.2); prior Dialysis with end stage renal disease (coeff: 0.7, 95% CI 0.1-1.1); prior use of Carbapenems (coeff: 1.3, 95% CI 0.3-2.3) and Stay in the ICU for more than 5 days (coeff: 2.4, 95% CI 1.6-3.2). It was validated prospectively in a subsequent cohort (n = 408) and the area-under-the-curve (AUC) of the GSDCS score for predicting nosocomial ICU acquired RGNB infection and bacteremia was 0.77 (95% CI 0.68-0.89 and 0.78 (95% CI 0.69-0.89) respectively. The GSDCS (0-4.3) score clearly differentiated the low (0-1.3), medium (1.4-2.3) and high (2.4-4.3) risk patients, both for RGNB infection (p:0.003) and bacteremia (p:0.009). CONCLUSION: GSDCS is a simple bedside clinical score which predicts RGNB infection and bacteremia with high predictive value and differentiates low versus high risk patients. This score will help clinicians to choose appropriate, timely targeted antibiotic therapy and avoid exposure to unnecessary treatment for patients at low risk of nosocomial RGNB infection. This will reduce the selection pressure and help to contain antibiotic resistance in ICUs.

Risk factors for infection/colonization caused by resistant Gram negative bacilli in critically ill patients (an observational study of 1633 critically ill patients).

OBJECTIVE: The objective of this study is to identify risk factors associated with multi-resistant Gram negative (RGNB) infection and colonization among critically ill patients. METHODS: A prospective cohort study of all patients aged 21-90 admitted for more than 24 hours in Medical and Surgical intensive care units (ICU) at a large teaching hospital in Singapore for the period of Aug '07-Dec '09 was conducted. Patient demographics, comorbidities, antibiotics, invasive devices, and culture results were collected. Forward stepwise logistic regression analyses were done to identify risk factors associated with RGNB infection and colonization. RESULTS: Of the 1373 patients included in the analysis, 13.5% developed RGNB infection. A logistic regression analysis including variables with a p value of <0.2 in the univariate analysis showed that recent surgery (OR 2.1, 95% CI 1.2-3.6), renal impairment (OR 2.9, 95% CI 1.5-5.4), liver disease (OR: 3.8, 95% CI 1.7-8.8), central line (OR 1.8, 95% CI 1.01-3.4) were independently associated with RGNB infection in the ICU. Surgery (OR 3.9, 95% CI 2.7-5.7), third-line antibiotics (carbapenem, vancomycin, linezolid) (OR 1.8, 95% CI 1.2-2.9) were independently associated with RGNB infection during their hospitalization. CONCLUSION: The major risk factors identified for RGNB infection and colonization in the ICU were mainly patient dependent. However, broad spectrum initial antibiotic treatment remains an important independent modifiable risk factor. Interventions aimed at reducing initial broad spectrum antibiotics are clearly needed to help control the spread of these difficult to treat infections.

Financial burden and financial aid for medical students in Singapore: a national survey across all three medical schools.

INTRODUCTION: Singapore has had three medical schools since 2013. We undertook a cross-sectional quantitative national survey to determine the financial impact of medical education on medical students in Singapore. METHODS: All 1,829 medical students in Singapore were invited to participate in this study. Information on demographics, financial aid utilisation and outside work was collected and analysed. RESULTS: 1,241 (67.9%) of 1,829 students participated in the survey. While the overall proportion of students from households with monthly incomes < SGD 3,000 was only 21.2% compared to the national figure of 31.4%, 85.4% of medical students expected to graduate with debts > SGD 75,000. There were significant differences in per capita incomes among the schools, with 54.5%, 23.3% and 7.8% of Duke-NUS Medical School (Duke-NUS), NUS Yong Loo Lin School of Medicine (NUS Medicine) and Lee Kong Chian School of Medicine (LKCMedicine) students, respectively, reporting a per capita income of < SGD 1,000 (p < 0.001). There were significant differences in financial support: 75.0%, 34.1% and 38.8% of Duke-NUS, NUS Medicine and LKCMedicine students, respectively, received financial aid (p < 0.001). The top reasons for not applying for aid included a troublesome application process (21.4%) and the perception that it would be too difficult to obtain (21.0%). CONCLUSION: Students in the three medical schools in Singapore differ in their financial needs and levels of financial support received. A national approach to funding medical education may be needed to ensure that financial burdens do not hamper the optimal training of doctors for Singapore's future.

A rapid simple point-of-care assay for the detection of SARS-CoV-2 neutralizing antibodies.

Background: Neutralizing antibodies (NAbs) prevent pathogens from infecting host cells. Detection of SARS-CoV-2 NAbs is critical to evaluate herd immunity and monitor vaccine efficacy against SARS-CoV-2, the virus that causes COVID-19. All currently available NAb tests are lab-based and time-intensive. Method: We develop a 10 min cellulose pull-down test to detect NAbs against SARS-CoV-2 from human plasma. The test evaluates the ability of antibodies to disrupt ACE2 receptor-RBD complex formation. The simple, portable, and rapid testing process relies on two key technologies: (i) the vertical-flow paper-based assay format and (ii) the rapid interaction of cellulose binding domain to cellulose paper. Results: Here we show the construction of a cellulose-based vertical-flow test. The developed test gives above 80% sensitivity and specificity and up to 93% accuracy as compared to two current lab-based methods using COVID-19 convalescent plasma. Conclusions: A rapid 10 min cellulose based test has been developed for detection of NAb against SARS-CoV-2. The test demonstrates comparable performance to the lab-based tests and can be used at Point-of-Care. Importantly, the approach used for this test can be easily extended to test RBD variants or to evaluate NAbs against other pathogens.

Severe community-acquired Acinetobacter baumannii pneumonia: an emerging highly lethal infectious disease in the Asia-Pacific.

BACKGROUND AND OBJECTIVE: Patients with community-acquired Acinetobacter baumannii (AB) pneumonia have been reported from subtropical countries. We investigated the epidemiology, clinical and microbiological characteristics of community-acquired pneumonia (CAP) due to AB in Singapore. METHOD: A retrospective case series was performed over a 21-month period at two institutions. RESULTS: From 1 January 2007 to 30 September 2008, eight patients were diagnosed with CAP due to AB. Seven had bacteraemia and five were sputum culture-positive. The median age at presentation was 58.5 years (range 45-76 years). Five patients (71.4%) acquired the pneumonia in the warmer months of June to September. Presentation was acute, with a median duration of 2.5 days (range 1-7 days). The median Acute Physiology and Chronic Health Evaluation II score was 28.5 (range 6-36). Six patients presented with septic shock, lactic acidosis, acute kidney injury and respiratory failure, necessitating ICU care; five of these patients eventually died. All patients received empirical antibiotics, including third-generation cephalosporins, which were inactive against the organism. All isolates were susceptible to ampicillin/sulbactam, ciprofloxacin, co-trimoxazole, aminoglycosides and imipenem. CONCLUSIONS: Community-acquired AB pneumonia have a fulminant course. In a region endemic for melioidosis and severe community-acquired Klebsiella pneumoniae, the challenge lies in rapid identification and initiation of appropriate empirical antibiotics to improve the survival of patients with AB CAP.

Persistent Dengue Infection in an Immunosuppressed Patient Reveals the Roles of Humoral and Cellular Immune Responses in Virus Clearance.

Detailed understanding of the roles of humoral and cellular immune responses in sterilizing dengue virus (DENV) infection in humans is required to inform effective vaccine development. We report an unusual case of persistent DENV infection in a lymphopenic renal transplant recipient who was therapeutically immunosuppressed to prevent organ rejection. Following resolution of symptomatic dengue, this patient remained positive for DENV3 RNA in the blood for 4 months and viruric up to 9 months post-infection despite demonstrable levels of serum neutralizing antibodies throughout this period. Full resolution of DENV infection instead coincided with recovery of CD8+ T cell counts during reversal from lymphopenia. Taken collectively, our observations suggest a role for cellular immunity in sterilizing DENV infection in humans. Any dengue vaccine should thus be able to induce both humoral and cellular immunity that respectively prevent symptomatic infection and enable effective viral clearance.

Epidemiology and outcomes of community-onset methicillin-susceptible Staphylococcus aureus bacteraemia in a university hospital in Singapore.

BACKGROUND: Methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia remains a condition associated with considerable morbidity and mortality worldwide. It is a common but little-studied problem outside of Europe and North America. METHODS: A single-centre retrospective case series profiling all patients with community onset-MSSA bacteraemia presenting between March 2005 and February 2006 to a tertiary acute-care university hospital in Singapore. In addition to epidemiological and clinical data collection, risk factors for complicated bacteremia and attributable mortality were analysed. RESULTS: A total of 100 patients met the case definition. Patients were more likely to be male (65%) and below 65 years of age (69%). Seventeen patients were intravenous drug abusers, while 38 had diabetes mellitus. There were 18 cases of endocarditis, with 11 occurring in intravenous buprenorphine abusers. Attributable mortality was 11%, and 46% of patients developed complicated bacteremia. On multivariate analysis, age > 65 years and presence of chronic pulmonary disease were the only significant risk factors for the former, while valvular heart disease was a significant risk factor for the latter. CONCLUSION: MSSA bacteraemia is associated with a significant risk of serious complications in Singapore. Other Asian cities should be alert to the risk factors for adverse outcomes for this important cause of morbidity and mortality.

The efficacy of influenza vaccination in healthcare workers in a tropical setting: a prospective investigator blinded observational study.

INTRODUCTION: Influenza vaccine has been shown to be highly effective in temperate regions with well-defined seasonal influenza. Healthcare workers (HCWs) are advised to receive regular influenza vaccination to protect themselves and their patients. However, there are limited data on the efficacy of influenza vaccine in HCWs in the tropics. MATERIALS AND METHODS: In this observational, investigator blinded cohort study, bi-monthly questionnaires recording influenza-like illness (ILI) episodes and medical leave were administered to 541 HCWs at the Singapore National University Hospital and KK Women's and Children's Hospital from 2004 to 2005. ILI was defined according to a standard symptom score. RESULTS: Baseline characteristics were comparable in both the vaccinated and non-vaccinated groups. Overall, the relative risk of self-reported ILI in vaccinated HCWs was 1.13 [95% confidence interval (CI), 0.98-1.13; P=0.107]; medical leave taken was lower in the vaccinated group [mean 0.26+/-0.6 days per visit, compared with 0.30+/-0.5 days in the non-vaccinated group (P=0.40)]. Because of the reported Northern Hemisphere 2003/04 vaccine mismatch, we stratified the cohort and determined that the group which received a matched vaccine had a relative risk of ILI of 0.49 (95% CI, 0.37-0.66; P<0.001), achieving a vaccine efficacy of 51%. Mean medical leave decreased significantly in HCWs who received the matched vaccine, compared with those who did not receive vaccination (0.13+/-0.3 vs 0.30+/-0.5; P<0.001) and with HCWs vaccinated with mismatched strains (0.13+/-0.3 vs 0.39+/-0.9; P=0.01). CONCLUSIONS: A well-matched influenza vaccine is effective in preventing ILI and reducing sickness absence in healthcare workers in tropical settings. Efforts need to be made to increase influenza vaccination rates and to improve the currently available vaccines.

Impact of financial background and student debt on postgraduate residency choices of medical students in Singapore.

INTRODUCTION: Medical school fees are rising globally. Student debt and financial background may affect residency choices, but few studies have been conducted in Asia. This study aimed to explore the relationship between financial background, student debt and postgraduate residency choices among medical students in Singapore. METHODS: An anonymised survey of all medical students in Singapore was conducted and had a response rate of 67.9%. RESULTS: 40.5% of our study population would graduate with debt. Medical students with monthly per capita household income < SGD 1,000 were more likely to graduate with debt (unadjusted odds ratio [OR] 2.0, 95% confidence interval [CI] 1.6-2.7; p < 0.001) and feel burdened by the cost of medical education (unadjusted OR 2.8, 95% CI 2.0-3.9; p < 0.001). Students with monthly per capita household income < SGD 1,000 (unadjusted OR 1.818, 95% CI 1.338-2.470, p < 0.001; adjusted OR 1.692, 95% CI 1.202-2.381, p = 0.003) and those with debt (unadjusted OR 1.623, 95% CI 1.261-2.090, p < 0.001; adjusted OR 1.393, 95% CI 1.048-1.851, p = 0.022) were more likely to rank at least one economic factor as 'very significant' in influencing their postgraduate training choices. CONCLUSION: It is concerning that despite financial aid schemes, the cost of medical education remains a burden to students from lower-income households in Singapore. Student debt and financial background may distort postgraduate career choices, creating an undue push towards high-paying specialties.

The costs of nosocomial resistant gram negative intensive care unit infections among patients with the systemic inflammatory response syndrome- a propensity matched case control study.

BACKGROUND: Infections due to multi-drug resistant gram negative bacilli (RGNB) in critically ill patients have been reported to be associated with increased morbidity and costs and only a few studies have been done in Asia. We examined the financial impact of nosocomial RGNB infections among critically ill patients in Singapore. METHODS: A nested case control study was done for patients at medical and surgical ICUs of a tertiary university hospital (August 2007-December 2011) matched by propensity scores. Two groups of propensity-matched controls were selected for each case patient with nosocomial drug resistant gram negative infection: at-risk patients with no gram negative infection or colonization (Control A) and patients with ICU acquired susceptible gram negative infection (SGNB) (Control B). The costs of the hospital stay, laboratory tests and antibiotics prescribed as well as length of stay were compared using the Wilcoxon matched-pairs signed rank test. RESULTS: Of the 1539 patients included in the analysis, 76 and 65 patients had ICU acquired RGNB and SGNB infection respectively. The median(range) total hospital bill per day for patients with RGNB infection was 1.5 times higher than at-risk patients without GNB infection [Singapore dollars 2637.8 (458.7-20610.3) vs. 1757.4 (179.9-6107.4), p0.0001]. The same trend was observed when compared with SGNB infected patients. The median costs per day of antibiotics and laboratory investigations were also found to be significantly higher for patients with RGNB infection. The length of stay post infection was not found to be different between those infected with RGNB and SGNB. CONCLUSION: The economic burden of RGNB infections to the patients and the hospital is considerable. Efforts need to be taken to prevent their occurrence by cost effective infection control practices.

Bacteraemic melioidosis pneumonia: impact on outcome, clinical and radiological features.

OBJECTIVES: Melioidosis is an endemic disease in South-east (SE) Asia and bacteraemia in melioidosis is associated with high mortality. We describe some clinical and radiological features of bacteraemic pneumonia due to Burkholderia pseudomallei as well as a comparison with bacteraemic patients without pneumonia. METHODS: Patients with positive blood cultures for B. pseudomallei from October 1997 to November 2001 were included. Patients were grouped as 'Pneumonia' and 'Non-pneumonia' according to clinical and radiological features. RESULTS: Eighteen (60%) out of total 30 patients were in the pneumonia group. There was no significant difference in age, WBC count, platelet counts and bilirubin levels between the groups. However the 'Pneumonia' group had higher incidences of hyponatraemia, acidosis, diabetes with poor control, renal impairment and shorter length of stay. Twelve (66%) of 18 patients in the pneumonia group required ICU admission compared to none in the non-pneumonia group; all required mechanical ventilation. Only 13/30 (43%) patients had initial empiric antibiotic therapy that is appropriate for melioidosis. The pneumonia group also had significantly higher mortality (13/18, 72%) rate than the non-pneumonia group (3/12, 25%, P=0.03). Chest radiographs were non-specific. 7/18 (38%) had unilobar involvement of the lung, mostly left sided; the rest had multilobar or bilateral involvement. Six (33%) had pleural effusion. No patient had cavitary lung disease. Visceral abscesses (spleen, liver and prostate) were also common in ultrasound and CT scans in both groups. CONCLUSION: (1) Bacteraemic melioidosis with pneumonia carries high mortality with most patients dying early. (2) Radiological features of melioidosis pneumonia are non-specific. (3) Clinicians who treat patients from SE Asia need to be aware of this condition to institute early and appropriate antibiotic therapy.

High burden of antimicrobial drug resistance in Asia.

The rapid development of antimicrobial resistance among micro-organisms is a serious public health concern. Moreover, the dissemination of antibiotic-resistant bacteria makes this issue a global problem, and Asia is no exception. For example, since New Delhi metallo-ß-lactamase (NDM)-producing Enterobacteriaceae were identified in India, further spread of NDM has become a worldwide threat. However, the epidemiology of antibiotic-resistant bacteria in Asia may be different to other regions, and clinical condition may be worse than in western countries. Antibiotic-resistant bacteria, including community-acquired and hospital-acquired meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA), vancomycin-resistant enterococci, macrolide- and penicillin-resistant Streptococcus pneumoniae, extend-spectrum ß-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, carbapenem-resistant Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa and Acinetobacter spp., are becoming prevalent in many countries in Asia. Moreover, the prevalence of each antibiotic-resistant bacterium in each country is not identical. This review provides useful information regarding the critical condition of antibiotic resistance in Asia and emphasises the importance of continuous surveillance of resistance data.

Neisseria gonorrhoeae paravertebral abscess.

The authors present the case of an isolated gonococcal paravertebral abscess with an epidural component in a 42-year-old man. A primary epidural abscess of the spine is a rare condition and is most commonly caused by Staphylococcus aureus. In this report, the authors present their therapeutic decisions and review the relevant literature on disseminated gonococcal infection in a patient presenting with an epidural abscess. A 42-year-old Indonesian man was admitted with symptoms of neck and upper back pain and bilateral lower-limb weakness. Clinical examination was unremarkable apart from tenderness over the lower cervical spine. Postgadolinium T1-weighted MRI of the cervical and thoracic spine demonstrated an enhancing lesion in the right paraspinal and epidural soft tissue at C-6 to T1-2, in keeping with a spinal epidural abscess. The patient underwent laminectomy of C-7 and T-1 with abscess drainage. Tissue cultures subsequently grew Neisseria gonorrhoeae that was resistant to quinolones by genotyping. Upon further questioning, the patient admitted to unprotected sexual intercourse with commercial sex workers. Further investigations showed that he was negative for other sexually transmitted infections. Postoperatively, he received a course of beta-lactam antibiotics with good recovery. Clinicians should be aware of this unusual disseminated gonococcal infection manifested in any patient with the relevant risk factors.