Simple, time saving pulsed-field gel electrophoresis protocol for the typing of Stenotrophomonas maltophilia

We developed a time-saving and cost-efficient Pulsed Field Gel Electrophoresis (PFGE) method for the typing of Stenotrophomonas maltophilia by modifying the conventional procedures. Our modifications related to the cell suspension preparation, lysis of bacterial cells in plugs, washing steps, and consumption of restriction enzyme. Although few rapid PFGE protocols on Gram-negative bacteria are available, the use of comparatively large amounts of costly reagents prompted us to look for other alternative. Hence, by considering the speed, simplicity, and relatively low cost, the modified protocol may be of more practical value than other established protocols in investigating S. maltophilia nosocomial outbreaks

Toxin gene profiling of methicillin-susceptible Staphylococcus aureus (MSSA) isolated from a Malaysian teaching hospital

Entero- and exfoliative toxin gene profiling of 237 methicillin-susceptible Staphylococcus aureus (MSSA) isolated from Universiti Kebangsaan Malaysia Medical Centre (UKMMC) were carried out via PCR amplification. Among the tested toxin genes, sei was found to be the most prevalent (54.9%)

Virulence gene typing of Methicillin-susceptible Staphylococcus aureus (MSSA)isolates in Universiti Kebangsaan Malaysia Medical Centre (UKMMC)

We determined the presence of four virulence genes: (cna, seh, PVL, TSST-1) using multiplex PCR in 880 isolates of methicillin-susceptible Staphylococcus aureus (MSSA) collected from the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2009. We found that 51.59% (454/880) of the strains had cna; 21.82% (192/880) possessed seh; 10.23% (90/880) had PVL and 6.82% (60/880) haboured TSST-1. Although methicillin-susceptible, MSSA carries important virulence genes which could affect patient’s clinical course

Species identification of Coagulase Negative Staphylococci (CoNS) isolates in Universiti Kebangsaan Malaysia Medical Centre (UKMMC)

Coagulase negative Staphylococcus (CoNS) are common colonizers of the human skin but has become increasingly recognized as agents of clinically significant infections. At the Universiti Kebangsaan Malaysia Medical Centre (UKMMC), the prevalence of CoNS among staphylococcus genus in 2009 was 47.1%. The aim of this study was to identify Staphylococcus epidermidis, S. saprophyticus and S. xylosus from the CoNS and MRCoNS (methicillin resistant CoNS) collected in 2009 using a multiplex PCR approach with primers specific for each species. Our results showed that S. epidermidis is the most common species among both MRCoNS and CoNS isolates in UKMMC. Among 1142 CoNS strains, 68.4% were S. epidermidis, 1.3% were S. saprophyticus while 30.3% were non-typeable (other species). A total of 659 CoNS strains have been identified as methicillin resistant (MRCoNS); where 68.1% were S. epidermidis,1.5% was S. saprophyticus and 30.3% were from other CoNS species. S. xylosus was not identified among the isolates

Screening and detection of heterogenous vancomycin intermediate Staphylococcus aureus in Hospital Kuala Lumpur Malaysia, using the glycopeptide resistance detection etest and population analysis profiling

In a 3-month study done in Hospital Kuala Lumpur (HKL), 7 out of 320 methicillin resistant Staphylococcus aureus isolates were confirmed as heterogeneous vancomycin intermediate S. aureus (hVISA) using the glycopeptide resistance detection e-test and population analysis, giving a prevalence rate of 2.19%. This is the first report of hVISA in Malaysia

Clonal Diversity of Methicillin-resistant Staphylococcus aureus in UKM Medical Centre: characterisation by Multilocus Sequence Typing of different SCCmec type representatives

Multilocus sequence typing (MLST) has been used to characterise methicillin-resistant Staphylococcus aureus (MRSA) isolates into sequence types (STs) and together with SCCmec typing, form the clonal nomenclature for MRSA. MLST was conducted as per the standard protocol on ten out of 236 isolates collected previously from January to December 2009 representing four different SCCmec types. Relationship analysis was performed with eBURST via the MLST website. Four unlinked ‘singleton’ STs were detected: ST30, ST239, ST772 and ST1178. Together with SCCmec typing, five MRSA clones were identified: ST30-IV, ST239-II, ST239-III, ST772-V and ST1178-IV. Clones ST239-III and ST30-IV are already established in Malaysian hospitals and in the local community, respectively. ST772-V is an emerging clone reported previously to have a propensity to displace pre-existing predominant clones. A clone involving the predominant ST in Malaysia (ST239) with SCCmec type II is the first of its kind to be identified. MRSA clones in our centre are very diverse and clone surveillance with large sample sizes should be undertaken as collaborative efforts between local institutions to maximise detection coverage

Activated ADI pathway: the initiator of intermediate vancomycin resistance in Staphylococcus aureus

Comparative proteomic profiling between two vancomycin intermediate Staphylococcus aureus (VISA) strains, Mu50Ω-vraSm and Mu50Ω-vraSm-graRm, and vancomycin-susceptible S. aureus (VSSA) strain Mu50Ω, revealed up-regulated levels of catabolic ornithine carbamoyltransferase (ArcB) of the arginine catabolism pathway in VISA. Subsequent analyses showed that the VISA strains have higher levels of cellular ATP and ammonia, which are by-products of arginine catabolism, and displayed thicker cell walls. We postulate that elevated cytoplasmic ammonia and ATP molecules, resulting from activated arginine catabolism upon acquisition of vraS and graR mutations, are important requirements facilitating cell wall biosynthesis, thereby contributing to thickened cell wall and consequently reduced vancomycin susceptibility in VISA.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author