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Title: Prevalence and Characterization of Heterogenous Vancomycin Intermediate Staphylococcus aureus Hvisa and Visa in a Tertiary Care Hospital of Northern India and their Possible Mechanism of Resistance
Researcher: Singh Avinash
Guide(s): J.K.Srivastava
University: Amity University
Completed Date: 2016
Abstract: Emergence of heterogeneous vancomycin intermediate Staphylococcus aureus (hVISA) strains has raised global concerns. hVISA strains are increasingly reported and their association with vancomycin treatment failure is a well-known problem worldwide. Currently several screening methods have been proposed for the detection of hVISA isolates, but the screening and identification methods are tediously time-consuming and hence are restricted to limited laboratories. Glycopeptides MIC increase within the susceptible range was observed among the clinical MRSA isolates at our centre over a 4-year period. Though no daptomycin MIC creep was observed in MRSA isolates, but the emergence of daptomycin non-susceptible hVISA strains calls for constant monitoring. Although the prevalence of hVISA was low but increasing trend over the periods was observed at our centre. Detection of daptomycin non-susceptible hVISA isolates is a major concern and thus it calls for judicious use of this drug. Since, the confirmatory PAP-AUC method is cumbersome and labour intensive, each clinical laboratory should use at least one screening method for early detection of hVISA. Further studies are needed to provide a better insight into the development of daptomycin non-susceptibility in some hVISA strains. This study demonstrates that the molecular epidemiology of VS-MRSA and hVISA is changing, and distinction between CA-MRSA and HA-MRSA is increasingly becoming blurred. CA-MRSA markers like SCCmec V and PVL are common in hVISA isolates at our centre. Whether such strains are truly introduced in our hospital from the community or there are some genetic resortment between CA- and HA-MRSA strains need further studies. Although the exact mechanism of thickening of cell wall in hVISA has not been determined, it is thought that the thickened cell wall prevents the diffusion of vancomycin into the cytoplasmic membrane leading to treatment failure. newline
Appears in Departments:Amity Institute of Biotechnology Lucknow

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1. cover page.pdfAttached File9.41 MBAdobe PDFView/Open
2. certificate.pdf9.41 MBAdobe PDFView/Open
3. prelimnary pages.pdf9.41 MBAdobe PDFView/Open
4. introduction.pdf9.41 MBAdobe PDFView/Open
5. review of literature.pdf9.41 MBAdobe PDFView/Open
6. materials & methods.pdf9.41 MBAdobe PDFView/Open
7. results.pdf9.41 MBAdobe PDFView/Open
8. discussion.pdf9.41 MBAdobe PDFView/Open
9. references.pdf9.41 MBAdobe PDFView/Open

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