Tracking the Emergence of Pandemic Influenza A/H1N1/2009 and its Interaction with Seasonal Influenza Viruses in Singapore

Introduction: Since the emergence of the pandemic influenza A/H1N1/2009 virus in April 2009, diagnostic testing in many countries has revealed the rapid displacement and then replacement of circulating seasonal influenza viruses by this novel virus. Materials and Methods: In-house seasonal and pandemic influenza-specific polymerase chain reaction assays were introduced and/or developed at the Molecular Diagnosis Centre (MDC) at the National University Hospital (NUH), Singapore. These assays have been used to test all samples received from in-patients, out-patients, staff and visitors for suspected pandemic influenza A/H1N1/2009 infection. Results: Prior to the arrival of the pandemic A/H1N1/2009 virus in Singapore at the end of May 2009, seasonal influenza A/H3N2 predominated in this population, with very little seasonal influenza A/H1N1 and B viruses detected. Within about 1 month of its arrival in Singapore (mainly during June to July 2009), this pandemic virus rapidly displaced seasonal influenza A/H3N2 to become the predominant strain in the Singaporean population served by MDC/NUH. Conclusions: Real-time molecular techniques have allowed the prompt detection of different influenza subtypes during this current pandemic, which has revealed the displacement/replacement of previously circulating seasonal subtypes with A/H1N1/2009. Although some of this may be explained by immunological cross-reactivity between influenza subtypes, more studies are required. Key words: Diagnostic, H1N1, Polymerase chain reaction

Tracking the emergence of pandemic Influenza A/H1N1/2009 and its interaction with seasonal influenza viruses in Singapore

INTRODUCTION

Since the emergence of the pandemic influenza A/H1N1/2009 virus in April 2009, diagnostic testing in many countries has revealed the rapid displacement and then replacement of circulating seasonal influenza viruses by this novel virus.

MATERIALS AND METHODS

In-house seasonal and pandemic influenza-specific polymerase chain reaction assays were introduced and/or developed at the Molecular Diagnosis Centre (MDC) at the National University Hospital (NUH), Singapore. These assays have been used to test all samples received from in-patients, out-patients, staff and visitors for suspected pandemic influenza A/H1N1/2009 infection.

RESULTS

Prior to the arrival of the pandemic A/H1N1/2009 virus in Singapore at the end of May 2009, seasonal influenza A/H3N2 predominated in this population, with very little seasonal influenza A/H1N1 and B viruses detected. Within about 1 month of its arrival in Singapore (mainly during June to July 2009), this pandemic virus rapidly displaced seasonal influenza A/H3N2 to become the predominant strain in the Singaporean population served by MDC/NUH.

CONCLUSIONS

Realtime molecular techniques have allowed the prompt detection of different influenza subtypes during this current pandemic, which has revealed the displacement/replacement of previously circulating seasonal subtypes with A/H1N1/2009. Although some of this may be explained by immunological cross-reactivity between influenza subtypes, more studies are required.

Galactomannan testing of bronchoalveolar lavage fluid is useful for diagnosis of invasive pulmonary aspergillosis in hematology patients

Background

Invasive pulmonary aspergillosis (IPA) is a major cause of morbidity and mortality in patients with hematological malignancies in the setting of profound neutropenia and/or hematopoietic stem cell transplantation. Early diagnosis and therapy has been shown to improve outcomes, but reaching a definitive diagnosis quickly can be problematic. Recently, galactomannan testing of bronchoalveolar lavage (BAL) fluid has been investigated as a diagnostic test for IPA, but widespread experience and consensus on optical density (OD) cut-offs remain lacking.

Methods

We performed a prospective case-control study to determine an optimal BAL galactomannan OD cutoff for IPA in at-risk patients with hematological diagnoses. Cases were subjects with hematological diagnoses who met established definitions for proven or probable IPA. There were two control groups: subjects with hematological diagnoses who did not meet definitions for proven or probable IPA and subjects with non-hematological diagnoses who had no evidence of aspergillosis. Following bronchoscopy and BAL, galactomannan testing was performed using the Platelia Aspergillus seroassay in accordance with the manufacturer's instructions.

Results

There were 10 cases and 52 controls. Cases had higher BAL fluid galactomannan OD indices (median 4.1, range 1.1-7.7) compared with controls (median 0.3, range 0.1-1.1). ROC analysis demonstrated an optimum OD index cutoff of 1.1, with high specificity (98.1%) and sensitivity (100%) for diagnosing IPA.

Conclusions

Our results also support BAL galactomannan testing as a reasonably safe test with higher sensitivity compared to serum galactomannan testing in at-risk patients with hematological diseases. A higher OD cutoff is necessary to avoid over-diagnosis of IPA, and a standardized method of collection should be established before results can be compared between centers.

Cost-effectiveness analysis of hospital infection control response to an epidemic respiratory virus threat

Pandemic (H1N1) 2009 can be contained with less expensive measures than some other viruses.

The outbreak of influenza A pandemic (H1N1) 2009 prompted many countries in Asia, previously strongly affected by severe acute respiratory syndrome (SARS), to respond with stringent measures, particularly in preventing outbreaks in hospitals. We studied actual direct costs and cost-effectiveness of different response measures from a hospital perspective in tertiary hospitals in Singapore by simulating outbreaks of SARS, pandemic (H1N1) 2009, and 1918 Spanish influenza. Protection measures targeting only infected patients yielded lowest incremental cost/death averted of $23,000 (US$) for pandemic (H1N1) 2009. Enforced protection in high-risk areas (Yellow Alert) and full protection throughout the hospital (Orange Alert) averted deaths but came at an incremental cost of up to $2.5 million/death averted. SARS and Spanish influenza favored more stringent measures. High case-fatality rates, virulence, and high proportion of atypical manifestations impacted cost-effectiveness the most. A calibrated approach in accordance with viral characteristics and community risks may help refine responses to future epidemics.

Carbapenems and subsequent multiresistant bloodstream infection: does treatment duration matter?

It has been proposed that initial empirical broad-spectrum antibiotic therapy will result in better clinical outcomes and that shorter courses will reduce the 'collateral damage' of promoting antibiotic resistance. There are few data from Intensive Care Units (ICUs) that support this latter conclusion. A prospective observational study was undertaken at the National University Hospital, Singapore, to examine the relationship between duration of carbapenem therapy and subsequent nosocomial multidrug-resistant (MDR) bloodstream infection (BSI). Over a 2-year period, 415 ICU patients receiving empirical carbapenem therapy were prospectively followed. MDR BSI occurred on 35 occasions in 31 patients, comprising 21 carbapenem-resistant Acinetobacter baumannii, 3 carbapenem-resistant Pseudomonas aeruginosa and 11 meticillin-resistant Staphylococcus aureus (MRSA). There was no difference in the duration of carbapenems for those who developed MDR BSI compared with those who did not [median duration 8 days (range 3-23 days) vs. 9 days (range 3-59 days); P=0.78]. On multivariate analysis using the Cox proportional hazard model the hazard ratio was 0.935 (P=0.070). In this cohort of critically ill patients, a shorter duration of carbapenem therapy was not shown to protect against subsequent development of MDR BSI. Strategies that depend primarily on reducing broad-spectrum antibiotic duration may be inadequate in preventing the emergence of MDR organisms.

Monkey malaria in humans: a diagnostic dilemma with conflicting laboratory data

Plasmodium knowlesi has recently been recognized as the fifth Plasmodium species causing malaria in humans. Diagnosis is difficult morphologically, and currently, available rapid tests have not been comprehensively evaluated with this pathogen. We report a case of P. knowlesi malaria that was confirmed after the initial clue of discordant microscopy and immunochromatographic results, highlighting the importance of molecular diagnostics in cases with the relevant clinical and epidemiologic history.

Cost of medical education, financial assistance and medical school demographics in Singapore

INTRODUCTION

Medical tuition fees have been rising in many countries, including in Singapore. No formal study has been conducted to evaluate the financial situation of medical students in relation to the cost of medical education in Singapore. This study was conducted to determine the financial profile of Singaporean medical students and the financial expenses they incur over the five-year duration of their undergraduate medical course.

METHODS

A questionnaire study was conducted among Year one to Year five medical students in the Yong Loo Lin School of Medicine, National University of Singapore. The following quantifiable parameters were analysed: monthly household income, financial assistance, monthly allowances and expenses.

RESULTS

64.3 percent (735) of the 1,143 undergraduates completed the survey. 21.9 percent came from families with a monthly income of less than S$3,000, with another 26.2 percent from families with monthly incomes of S$3,000-S$5,000. The total tuition fees for a five-year medical course amounted to S$87,450. The average annual expenditure of medical students amounted to S$4,470. 31.1 percent of respondents were on loans. 14.6 percent received scholarships or bursaries.

CONCLUSION

A five-year medical course can cost more than S$100,000 and pose a significant financial burden for students. The proportion of students who came from lower-income families was lower in medical school than at the national level, while the proportion from high-income families was significantly higher than at the national level. A significant proportion of students took loans to pay for tuition, and a smaller percentage was under scholarships and bursaries. More substantial financial assistance is required, particularly for students from lower-income families.

Methicillin-resistant Staphylococcus aureus control at the National University Hospital, Singapore: a historical perspective

INTRODUCTION

The National University Hospital (NUH) was the first restructured public hospital in Singapore. As the most recently established hospital in Singapore, it has a unique record of alert organisms including methicillin-resistant Staphylococcus aureus (MRSA).

MATERIALS AND METHODS

We performed a critical review of multiple data sources including surveillance reports, task force reports, published abstracts and manuscripts concerning MRSA in NUH.

RESULTS

Three themes emerged: 1) the MRSA rates have remained relatively stable through the life of the hospital despite the increased complexity of patients and intermittent intensified control efforts; 2) the major MRSA task forces were driven by surgeons and 3) a scientific approach to epidemiology has a critical role in understanding and planning interventions.

CONCLUSION

Although containment of MRSA can be accomplished to a certain degree through mobilisation of existing resources, higher goals such as eradication would require massive infusions of infrastructural, scientific and human resources to have a chance of success.

Use of multiple methods for genotyping Fusarium during an outbreak of contact lens associated fungal keratitis in Singapore

Background

In Singapore, an outbreak of fungal keratitis caused by members of the Fusarium solani species complex (FSSC) was identified in March 2005 to May 2006 involving 66 patients. Epidemiological investigations have indicated that improper contact lens wear and the use of specific contact lens solutions were risk factors.

Methods

We assessed the genetic diversity of the isolates using AFLP, Rep-PCR, and ERIC-PCR and compared the usefulness of these typing schemes to characterize the isolates.

Results

AFLP was the most discriminative typing scheme and appears to group FSSC from eye infections and from other infections differently.

Conclusion

There was a high genomic heterogeneity among the isolates confirming that this was not a point source outbreak.

Update on influenza vaccines

Vaccination has been the most effective means for control of viral infections for centuries. While seasonal vaccines have been highly effective in the management of influenza, there are a number of obstacles to the development of safe and effective pandemic influenza vaccines. The good news is that there has been a lot of investment into novel approaches including reverse genetics and whole cell vaccines that hold promise for successful pandemic control if they can be rolled out in time.

Update on influenza anti-virals

While the mainstay of prevention and control of any viral infection has historically been the use of vaccines, it is recognized that the pace of a global pandemic is likely to be such that it is unlikely that an effective vaccine will be ready for the first wave of an influenza pandemic. As such, in addition to non-pharmacological public health and infection control measures, the first line of action will be the use of antivirals.

Twentieth Century Influenza Pandemics in Singapore

Introduction: Singapore was substantially affected by three 20th Century pandemics. This study describes the course of the pandemics, and the preventive measures adopted. Materials and Methods: We reviewed and researched a wide range of material including peer-reviewed journal articles, Ministry of Health reports, Straits Settlements reports and newspaper articles. Monthly mortality data were obtained from various official sources in Singapore. Results: The 1918 epidemic in Singapore occurred in 2 waves – June to July, and October to November – resulting in up to 3500 deaths. The 1957 epidemic occurred in May, and resulted in widespread morbidity, with 77,000 outpatient attendances in government clinics alone. The 1968 epidemic occurred in August and lasted a few weeks, with outpatient attendances increasing by more than 65%. The preventive measures instituted by the Singapore government during the pandemics included the closure of schools, promulgation of public health messages, setting up of influenza treatment centres, and screening at ports. Students, businessmen and healthcare workers were all severely affected by the pandemics. Conclusions: Tropical cities should be prepared in case of a future pandemic. Some of the preventive measures used in previous pandemics may be applicable during the next pandemic.

A clinical trial of a whole-virus H5N1 vaccine derived from cell culture

BACKGROUND

Widespread infections of avian species with avian influenza H5N1 virus and its limited spread to humans suggest that the virus has the potential to cause a human influenza pandemic. An urgent need exists for an H5N1 vaccine that is effective against divergent strains of H5N1 virus.

METHODS

In a randomized, dose-escalation, phase 1 and 2 study involving six subgroups, we investigated the safety of an H5N1 whole-virus vaccine produced on Vero cell cultures and determined its ability to induce antibodies capable of neutralizing various H5N1 strains. In two visits 21 days apart, 275 volunteers between the ages of 18 and 45 years received two doses of vaccine that each contained 3.75 microg, 7.5 microg, 15 microg, or 30 microg of hemagglutinin antigen with alum adjuvant or 7.5 microg or 15 microg of hemagglutinin antigen without adjuvant. Serologic analysis was performed at baseline and on days 21 and 42.

RESULTS

The vaccine induced a neutralizing immune response not only against the clade 1 (A/Vietnam/1203/2004) virus strain but also against the clade 2 and 3 strains. The use of adjuvants did not improve the antibody response. Maximum responses to the vaccine strain were obtained with formulations containing 7.5 microg and 15 microg of hemagglutinin antigen without adjuvant. Mild pain at the injection site (in 9 to 27% of subjects) and headache (in 6 to 31% of subjects) were the most common adverse events identified for all vaccine formulations.

CONCLUSIONS

A two-dose vaccine regimen of either 7.5 microg or 15 microg of hemagglutinin antigen without adjuvant induced neutralizing antibodies against diverse H5N1 virus strains in a high percentage of subjects, suggesting that this may be a useful H5N1 vaccine. (ClinicalTrials.gov number, NCT00349141.)

Twentieth century influenza pandemics in Singapore

INTRODUCTION

Singapore was substantially affected by three 20th Century pandemics. This study describes the course of the pandemics, and the preventive measures adopted.

MATERIALS AND METHODS

We reviewed and researched a wide range of material including peer-reviewed journal articles, Ministry of Health reports, Straits Settlements reports and newspaper articles. Monthly mortality data were obtained from various official sources in Singapore.

RESULTS

The 1918 epidemic in Singapore occurred in 2 waves--June to July, and October to November--resulting in up to 3500 deaths. The 1957 epidemic occurred in May, and resulted in widespread morbidity, with 77,000 outpatient attendances in government clinics alone. The 1968 epidemic occurred in August and lasted a few weeks, with outpatient attendances increasing by more than 65%. The preventive measures instituted by the Singapore government during the pandemics included the closure of schools, promulgation of public health messages, setting up of influenza treatment centres, and screening at ports. Students, businessmen and healthcare workers were all severely affected by the pandemics.

CONCLUSIONS

Tropical cities should be prepared in case of a future pandemic. Some of the preventive measures used in previous pandemics may be applicable during the next pandemic.

Screening for Vancomycin-resistant Enterococci Using Stools Sent for Clostridium difficile Cytotoxin Assay is Effective: Results of a Survey of 300 Patients in a Large Singapore Teaching Hospital

Introduction: To assess the efficacy of screening stools sent for Clostridium difficile cytotoxin assay (CDTA) for surveillance of vancomycin-resistant enterococci (VRE). Materials and Methods: From April to May 2005, all stools submitted for CDTA were also cultured for VRE using vancomycin containing culture media. Isolates were identified to species level and vancomycin resistance confirmed, followed by polymerase chain reaction (PCR) for detection of vancomycin resistance genes and DNA fingerprinting. Over 2 consecutive days during that period, stool specimens or rectal swabs were also obtained from all patients in high-risk units (haematology, oncology, renal and intensive care). Fifty-one patients in each group were compared in terms of VRE risk factors previously identified. Results and Discussion: The prevalence of VRE in both groups was similar [3/204 (1.5%) in the CDTA arm and 1/97 (1.0%) in the high-risk arm; P = 1.0, Fisher’s exact test]. Prevalence of risk factors for VRE colonisation, including age, duration of hospitalisation, exposure to antibiotics, exposure to surgical procedures, presence of malignancy and diabetes mellitus was similar in both groups (P > 0.05). Only renal failure (P < 0.05) was more common in the high-risk group. All 4 isolates of VRE identified were genetically distinct by variable number tandem repeat (VNTR) typing; 3 were Enterococcus faecium (2 with the vanB gene, 1 with vanA) and one E. faecalis. Conclusion: Less than 2% of our high-risk patients are VRE carriers. In-hospital VRE screening using stools sent for CDTA is a simple, reasonable surrogate for screening individual high-risk patients as the patient risk profile is similar and the yield comparable in a low-prevalence setting. Key words: Antibiotic resistance, Surveillance, Vancomycin-resistant enterococci

European and Asian guidelines on management and prevention of catheter-associated urinary tract infections

We surveyed the extensive literature regarding the development, therapy and prevention of catheter-associated urinary tract infections (UTIs). We systematically searched for meta-analyses of randomised controlled trials available in Medline giving preference to the Cochrane Central Register of Controlled Trials and also considered other relevant publications, rating them on the basis of their quality. The studies' recommendations, rated according to a modification of the US Department of Health and Human Services (1992), give a close-to-evidence-based guideline for all medical disciplines, with special emphasis on urology where catheter care is an important issue. The survey found that the urinary tract is the commonest source of nosocomial infection, particularly when the bladder is catheterised (IIa). Most catheter-associated UTIs are derived from the patient's own colonic flora (IIb) and the catheter predisposes to UTI in several ways. The most important risk factor for the development of catheter-associated bacteriuria is the duration of catheterisation (IIa). Most episodes of short-term catheter-associated bacteriuria are asymptomatic and are caused by a single organism (IIa). Further organisms tend to be acquired by patients catheterised for more than 30 days. The clinician should be aware of two priorities: the catheter system should remain closed and the duration of catheterisation should be minimal (A). While the catheter is in place, systemic antimicrobial treatment of asymptomatic catheter-associated bacteriuria is not recommended (A), except for some special cases. Routine urine culture in an asymptomatic catheterised patient is also not recommended (C) because treatment is in general not necessary. Antibiotic treatment is recommended only for symptomatic infection (B). Long-term antibiotic suppressive therapy is not effective (A). Antibiotic irrigation of the catheter and bladder is of no advantage (A). Routine urine cultures are not recommended if the catheter is draining properly (C). A minority of patients can be managed with the use of the non-return (flip) valve catheter, avoiding the closed drainage bag. Such patients may exchange the convenience of on-demand drainage with an increased risk of infection. Patients with urethral catheters in place for 10 years or more should be screened annually for bladder cancer (C). Clinicians should always consider alternatives to indwelling urethral catheters that are less prone to causing symptomatic infection. In appropriate patients, suprapubic catheters, condom drainage systems and intermittent catheterisation are each preferable to indwelling urethral catheterisation (B).

Screening for vancomycin-resistant enterococci using stools sent for Clostridium difficile cytotoxin assay is effective: results of a survey of 300 Patients in a large Singapore Teaching Hospital

INTRODUCTION

To assess the efficacy of screening stools sent for Clostridium difficile cytotoxin assay (CDTA) for surveillance of vancomycin-resistant enterococci (VRE).

MATERIALS AND METHODS

From April to May 2005, all stools submitted for CDTA were also cultured for VRE using vancomycin containing culture media. Isolates were identified to species level and vancomycin resistance confirmed, followed by polymerase chain reaction (PCR) for detection of vancomycin resistance genes and DNA fingerprinting. Over 2 consecutive days during that period, stool specimens or rectal swabs were also obtained from all patients in high-risk units (haematology, oncology, renal and intensive care). Fifty-one patients in each group were compared in terms of VRE risk factors previously identified.

RESULTS AND DISCUSSION

The prevalence of VRE in both groups was similar [3/204 (1.5%) in the CDTA arm and 1/97 (1.0%) in the high-risk arm; P = 1.0, Fisher's exact test]. Prevalence of risk factors for VRE colonisation, including age, duration of hospitalisation, exposure to antibiotics, exposure to surgical procedures, presence of malignancy and diabetes mellitus was similar in both groups (P > 0.05). Only renal failure (P < 0.05) was more common in the high-risk group. All 4 isolates of VRE identified were genetically distinct by variable number tandem repeat (VNTR) typing; 3 were Enterococcus faecium (2 with the vanB gene, 1 with vanA) and one E. faecalis.

CONCLUSION

Less than 2% of our high-risk patients are VRE carriers. In-hospital VRE screening using stools sent for CDTA is a simple, reasonable surrogate for screening individual high-risk patients as the patient risk profile is similar and the yield comparable in a low-prevalence setting.

Risk factors for contact lens-related fusarium keratitis: a case-control study in Singapore

OBJECTIVE

To evaluate the specific contact lens-related or other factors that may contribute to the outbreak of Fusarium keratitis.

METHODS

A case-control study was conducted of Fusarium keratitis in contact lens users in Singapore from March 1, 2005, to May 31, 2006, and included 61 patients with Fusarium keratitis and 188 population-based and 179 hospital-based control subjects. Interviewers asked about contact lens solution use and other risk factors.

RESULTS

Patients with Fusarium keratitis were more likely to use ReNu contact lens solutions (Bausch & Lomb, Rochester, NY) 58 [95.1%] of 61 cases) than were either population-based (62 [34.3%] of 181) or hospital-based (50 [30.1%] of 166) control subjects. After controlling for age, sex, contact lens hygiene, and other factors, the use of ReNu with MoistureLoc significantly increased the risk of Fusarium keratitis (odds ratio, 99.3; 95% confidence interval, 18.4-535.4; P<.001), and the risk was 5 times higher compared with the risk with use of ReNu MultiPlus, a multipurpose solution (odds ratio, 21.5; 95% confidence interval, 4.0-115.5; P<.001).

CONCLUSIONS

The use of ReNu contact lens solutions significantly increased the risk of contact lens-related Fusarium keratitis in Singapore. Our data support the recall of ReNu MultiPlus from the Singapore market and the need for further investigations into the role of ReNu MultiPlus in the development of Fusarium keratitis in other populations.

Outpatient parenteral antibiotic therapy in Singapore

Outpatient parenteral antibiotic therapy (OPAT) remains in its infancy in Singapore, with the first patients enrolled 4 years ago. Singapore's three largest hospitals, with over 3000 inpatient beds, now have designated and approved OPAT services. This study reviews the demographic, clinical and cost data of all patients enrolled in 2005 to facilitate benchmarking between services in Singapore and abroad and also to identify common needs for further development. In 2005, 225 OPAT enrollments in 208 different patients resulted in 4050 days of OPAT care. Orthopaedic diagnoses constituted 40% of admissions. Vancomycin was the most frequently used antibiotic (34%). The re-admission rate was 8.9%, but complications of OPAT care were only occasionally implicated. An estimated $207,200 was saved by patients despite there being significant financial disincentives to subsidised patients. OPAT is a safe, cost-efficient system that is becoming increasingly accepted in Singapore by patients, clinicians and management. Our three services have evolved independently into very similar practices. There is potential for further innovation, including outreach and carer-delivered dosing. However, major financial disincentives require review.

An outbreak of Fusarium keratitis associated with contact lens wear in Singapore

CONTEXT

Fungal keratitis is a potentially blinding condition that is rarely seen with contact lens wear.

OBJECTIVE

To describe a nationwide outbreak of fungal keratitis caused by Fusarium species among contact lens wearers in Singapore.

DESIGN, SETTING, AND PATIENTS

Nationwide, hospital-based case series. All cases of fungal keratitis among contact lens wearers in all ophthalmology departments in Singapore were reviewed along with the charts of all contact lens wearers with culture-proven fungal keratitis from March 2005 through May 2006. A standardized telephone interview was conducted to obtain additional clinical information.

MAIN OUTCOME MEASURE

Diagnosis of Fusarium keratitis associated with contact lens wear.

RESULTS

During the study period, 66 patients (68 affected eyes) were diagnosed with Fusarium keratitis associated with contact lens wear; the estimated annual national incidence is 2.35 cases per 10,000 contact lens wearers (95% confidence interval, 0.62-7.22). Patients ranged in age from 13 to 44 years (mean [SD], 27.1 [8.4] years), of which 32 (48.5%) were men. The vast majority (65 patients; 98.5%) wore soft, disposable contact lenses; 62 patients (93.9%) reported using 1 brand of contact lens cleaning solution (ReNu, Bausch & Lomb, Rochester, NY), including 42 patients (63.6%) who recalled using ReNu with MoistureLoc. Most patients (81.8%) reported poor contact lens hygiene practices, including overnight use of daily wear contact lenses (19.7%), and use of contact lenses past the replacement date (43.9%). The final best-corrected visual acuity ranged from 20/20 to 20/80. Five patients (5 eyes; 7.4%) required emergency therapeutic or tectonic corneal transplantation.

CONCLUSIONS

A new and evolving epidemic of Fusarium keratitis associated with contact lens wear was found in Singapore. Physicians and eye care practitioners worldwide need to be aware of the likelihood of similar outbreaks emerging among contact lens wearers.

Practical management of avian influenza in humans

There has been much alarm about avian influenza and its potential for a global pandemic ever since the current epidemic of avian influenza infections in humans began in 2003. While there have been a number of published reports on the clinical features of avian influenza, there are few guidelines on the practical management of patients with avian influenza. A symposium organised by the Society of Infectious Disease (Singapore), Society of Intensive Care Medicine and the Singapore General Hospital was held in Singapore to gather the views of experts from Turkey, Thailand, Vietnam and Indonesia who collectively had first-hand experience of the management of the majority (more than 100 of 192) of cases of avian influenza worldwide. The experts emphasised the importance of adapting international guidelines to the practicalities of situations on the ground. There was stress on wide screening using clinical criteria primarily, molecular diagnostic techniques (with reference laboratory confirmation) for diagnosis, and rational use of antiviral prophylaxis as well as infection control using at least surgical masks, gowns and gloves. A detailed analysis of data from a pooled database from these and other affected countries is critical to building up the evidence base for practical internationally applicable guidelines.

Selection of medical students in Singapore: a historical perspective

The selection of medical students in Singapore has been a contentious issue for more than 140 years. Initially, students were selected for Madras Medical College, the traditional source for medical officers in early Singapore, by a combination of an examination as well as an observed preceptorship at the General Hospital. With the establishment of the medical school in Singapore in 1905, the selection criteria have been progressively refined over the years. These have included a baseline academic threshold, linguistic competence and performance at an interview. In the past, other criteria such as gender and political suitability were important but at the present, only hepatitis B virologic status is a limiting factor for otherwise qualified applicants. Singapore's Ministry of Health reports an attrition rate of 10% from our medical school. This poses a challenge as there are far more qualified applicants for medical school in Singapore than there are places. This is a worldwide problem and locally, attempts are being made to further refine the admission process to ensure that the community as a whole is best served by the future doctors we select.

Paraneoplastic progressive supranuclear palsy syndrome in a patient with B-cell lymphoma

An important component in the diagnosis of atypical parkinsonian disorders is the exclusion of secondary causes. Paraneoplastic causes of parkinsonism are extremely rare. We describe a case which presented initially as probable progressive supranuclear palsy (PSP) but on follow-up displayed a rapidly progressive course, unexplained fever, peripheral neuropathy and an abnormal CSF. We highlight the difficulties faced in formulating a diagnosis for this unusual case prior to the discovery of an occult B-cell lymphoma, and discuss its relevance in the exclusion criteria for PSP. A paraneoplastic cause should be considered if disease progression is unusually rapid.

Methicillin-resistant Staphylococcus aureus endocarditis after transurethral prostatic resection

We report the first case, to our knowledge, of methicillin-resistant Staphylococcus aureus endocarditis complicating transurethral prostatic resection for benign prostatic hyperplasia. The patient had been catheterized preoperatively because of urinary retention and, postoperatively, developed pyrexia with persistent methicillin-resistant S. aureus-positive blood cultures. The cause remained elusive, despite extensive investigations (including echocardiography), until he developed embolic phenomena pathognomonic of infective endocarditis 1 month into treatment with intravenous vancomycin.

Tuberculosis post-liver transplantation: a rare but complicated disease

INTRODUCTION

Tuberculosis is a rare but serious complication after transplantation. We report a case and discuss its presentation and management.

CLINICAL PICTURE

A 60-year-old Indonesian male presented initially with fever, acute confusion and rapidly progressive right upper lobe pneumonia 3.5 months post-liver transplant, and was diagnosed with pulmonary tuberculosis by positive sputum smear for acid-fast bacilli and tuberculosis culture.

TREATMENT/OUTCOME

Standard anti-tuberculosis therapy was administered but was complicated by interaction with cyclosporine and drug-induced cholestasis.

CONCLUSION

A high level of suspicion, prompt antituberculosis treatment and close follow-up are essential in management of post-transplant tuberculosis.

Severe acute respiratory syndrome from the trenches, at a Singapore university hospital

The epidemiology and virology of severe acute respiratory syndrome (SARS) have been written about many times and several guidelines on the infection control and public health measures believed necessary to control the spread of the virus have been published. However, there have been few reports of the problems that infectious disease clinicians encounter when dealing with the protean manifestations of this pathogen. This is a qualitative account of some of the issues faced by an infectious disease physician when identifying and treating patients with SARS as well as protecting other healthcare workers and patients, including: identification of the chain of contagion, early recognition of the disease in the absence of a reliable and rapid diagnostic test, appropriate use of personal protective equipment, and the use of isolation to prevent super-spreading events. Many issues need to be addressed if clinicians are to be able to manage the virus should it reappear.

Nosocomial infection with vancomycin-dependent enterococci

In three patients with nosocomial vancomycin-resistant enterococcal infections, infections attributable to vancomycin-dependent enterococci developed.

We report three patients infected with unique strains of vancomycin-dependent enterococci. Two were first infected by genetically identical strains of vancomycin-resistant enterococci (VRE). All three patients had much greater exposure to vancomycin and third-generation cephalosporins than did two control groups (patients infected with VRE and hospitalized patients without enterococcal infections). While antimicrobial pressure promotes nosocomial colonization by VRE, prolonged exposure to vancomycin may foster the transition from vancomycin resistance to dependence.

Catheter-associated urinary tract infections: diagnosis and prophylaxis

Catheter-associated urinary tract infections (CAUTI) are the commonest nosocomial infections worldwide. While they are often asymptomatic and frequently cost less than nosocomial surgical site infections or nosocomial pneumonia, they are major reservoirs of antimicrobial resistant pathogens. Numerous strategies have been devised in an attempt to reduce the incidence of CAUTI but few have proven effective. Novel technologies such as the potential use of antiseptic or antimicrobial coatings on catheters hold promise for possibly reducing these infections in the fight against antimicrobial resistance.

SARS: responding to an unknown virus

The severe acute respiratory syndrome (SARS) is an emerging infection caused by a novel coronavirus which first appeared in southern China at the end of 2002. In early 2003, through a single incident, it spread to Hong Kong, Singapore, Canada and Vietnam. For busy clinicians in large public hospitals, the response to the virus was initially based on ensuring a high level of protection for staff. However, as the epidemic progressed and more information became available about the virus, procedures were rationalized and the virus is currently under control worldwide. There are, however, numerous unanswered questions concerning super-spreading events, the modes of transmission of the virus and, perhaps most importantly, the rapid detection of the virus early in the course of disease. These issues need to be addressed in case the virus becomes more widespread in the near future.

Confusion in travellers

Acute onset long haul in-flight confusion, restlessness, disorientation and abnormal behaviour in a 24 year old lady who had recent typhoid fever is reported. Confusion in travelers within the context of infections, including typhoid psychosis, and other causes, is discussed to enlighten practitioners on the problem, and ensuing potential medico-legal and ethical issues.

Mild illness associated with severe acute respiratory syndrome coronavirus infection: lessons from a prospective seroepidemiologic study of health-care workers in a teaching hospital in Singapore

BACKGROUND

Severe acute respiratory syndrome (SARS) is a newly recognized infectious disease that has recently emerged in East Asia and North America. Although the clinical features of acute infection have been well described, mildly symptomatic or asymptomatic infections have not been well characterized.

OBJECTIVE

To assess the spectrum of illness in health-care workers (HCWs).

METHODS

A prospective seroepidemiologic cohort study was conducted on 372 HCWs in a large teaching hospital in Singapore who were both exposed and not exposed to patients with SARS. Participating HCWs completed a questionnaire and provided paired serum samples, which were analyzed by 2 different laboratories blinded to clinical data, by use of an enzyme-linked immunosorbent assay based on a protocol developed by the Centers for Disease Control and Prevention and a dot-blot immunoassay, with confirmation by a viral neutralization assay.

RESULTS

A total of 21 patients with SARS were treated at our hospital. They were associated with transmission to 14 staff members, patients, and visitors in our hospital. Of the 372 HCWs participating in the present study, 8 were found to have positive antibodies to the SARS coronavirus in both samples by use of both test methods, and 6 had pneumonia and had been hospitalized for either probable or suspected SARS infection, whereas 2 had fever but did not have changes on chest radiographs. All seropositive HCWs had been exposed either directly or indirectly to patients with SARS. No asymptomatic, nonexposed staff members were found to be seropositive. There was a trend towards protection for HCWs who, while fully protected, had had contact with patients with SARS.

CONCLUSIONS

Although the majority of cases of SARS are associated with pneumonia, a small number of mildly symptomatic individuals do seroconvert. HCWs who are exposed to patients with SARS can be infected with SARS, regardless of the intensity of exposure. This has implications for surveillance and infection control planning, in the event that SARS returns next winter.