Vancomycin-resistant Enterococci in Singaporean hospitals: 5-year results of a multi-centre surveillance programme

<p><b>INTRODUCTION</b>Vancomycin-resistant enterococci (VRE) have emerged as one of the major nosocomial antimicrobial-resistant pathogens globally. In this article, we describe the epidemiology of VRE in Singaporean public hospitals in the 5 years following the major local VRE outbreak in 2005.</p><p><b>MATERIALS AND METHODS</b>A passive laboratory surveillance programme identified non-duplicate VRE isolates from 7 hospitals from 2006 to 2010. Descriptive statistics and time-series analysis was performed on all clinical VRE isolates for each individual hospital as well as for the combined dataset.</p><p><b>RESULTS</b>There were a total of 418 VRE isolates over 5 years, of which 102 isolates (24.4%) were from clinical cultures. Between 0.4% and 0.7% of all clinical enterococcal isolates were resistant to vancomycin. The overall incidence-density of VRE did not change over time in Singapore despite 2 separate outbreaks in tertiary hospitals in 2009 and 2010. Incidence-density of clinical VRE cases fell in 2 secondary hospitals, while another 2 hospitals experienced no significant VRE infections after 2008.</p><p><b>CONCLUSION</b>The prevalence of VRE clinical isolates remains low in Singaporean public sector hospitals. However, the presence of at least 2 outbreaks in separate hospitals over the past 5 years indicates the need for continued vigilance in order to prevent any further increase in VRE prevalence locally.</p>

Antibiotic resistance in gram-negative bacilli: a Singapore perspective

<p><b>INTRODUCTION</b>Antibiotic resistance in gram-negative bacilli is an area of increasing importance. This prospective study was performed to survey antibiotic resistance in Escherichia coli (E. coli), Klebsiella spp., Pseudomonas aeruginosa and Acinetobacter spp. over a 1-year period.</p><p><b>MATERIALS AND METHODS</b>Non-duplicate isolates of E. coli, Klebsiella spp., P. aeruginosa and Acinetobacter spp. were collected from participating Singapore hospitals during defined collection periods in 2006 and 2007. Confirmatory identification and antibiotic susceptibility testing were performed at Changi General Hospital. Minimum inhibitory concentrations (MIC) to a defined panel of antibiotics were determined using microbroth dilution methods. The presence of extended-spectrum beta lactamases and AmpC beta-lactamases in Enterobacteriaceae was determined by phenotypic methods, and susceptibility results were defined using current breakpoints from the Clinical Laboratory Standards Institute (CLSI).</p><p><b>RESULTS</b>Seven hundred and forty-six gram-negative bacilli were received for testing. Resistance to extended-spectrum cephalosporins was present in a third of Enterobacteriaceae isolates, and extended-spectrum beta-lactamases (ESBL) carriage was present in 19.6% and 30.1% of E. coli and Klebsiella pneumoniae, respectively. AmpC enzymes were also detected in 8.5% and 5.6% of E. coli and K. pneumoniae isolates respectively. All Enterobacteriaceae were susceptible to imipenem and meropenem. The most active antibiotics against P. aeruginosa were amikacin, meropenem and piperacillin-tazobactam. A third of P. aeruginosa showed reduced susceptibility to polymyxin B. Carbapenem resistance was significantly higher in Acinetobacter baumannii (70.5%) than in other Acinetobacter species (25.0%). The most active antibiotic against A. baumannii was polymyxin B.</p><p><b>CONCLUSION</b>Antibiotic resistance is prevalent in gram-negative bacilli isolated from Singapore hospitals. The MIC testing surveillance programme complemented susceptibility data from wider laboratory-based surveillance, and has revealed emerging mechanisms of antibiotic resistance.</p>

Cluster of Staphylococcus aureus and dengue co-infection in Singapore

<p><b>INTRODUCTION</b>Singapore saw a resurgence of dengue infections in 2005. Concurrent bacterial co-infections in dengue is rare.</p><p><b>CLINICAL PICTURE</b>We report a cluster of serious methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia or severe soft tissue infection in 5 epidemiologically linked construction workers presenting with dengue and non-resolving fever.</p><p><b>TREATMENT</b>Surgical intervention was indicated in 4 of the 5 patients despite appropriate antistaphylococcal therapy.</p><p><b>OUTCOME</b>All but 1 patient were eventually discharged. Clonality and Panton-Valentine leucocidin genes were not demonstrated. Epidemiological investigations suggested that occupational contact dermatitis could have predisposed the patients to this opportunistic co-infection.</p><p><b>CONCLUSION</b>Clinicians need to be vigilant to unusual manifestations of dengue which may signal a concomitant aetiology.</p>