Medical Sciences

Title :

Characterization of genes responsible for carbapenem resistance in Enterobacteriaceae from clinical and environmental samples

Area of research :

Medical Sciences

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Principal Investigator :

Dr. B. N. Harish, Professor, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry

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Executive Summary :

Carbapenems represents last line antibiotic that are still effective in treating enterobacterial infections. The emergence of carbapenemase-producing Enterobacteriaceae is worrying and hence the study has been conducted. Production of carbapenemases such as blaNDM-1 and blaOXA 48, deficiency of outer membrane protein (OMP36) and enhanced efflux pump activity was characterized. In addition, prevalence and antimicrobial susceptibility patterns of Enterobacteriaceae isolates was evaluated in water samples. Multiplex PCR assay was optimized to detect blaNDM-1, blaOXA 48 and OMP 36 genes, and sequencing was carried out subsequently. No other genes such as blaIMP, blaVIM and blaKPC were identified in this study. Efflux pump inhibitor test was performed for NDM-1and OXA 48 negative strains using Phenyl Alanine ? Naphthylamide (PABN) inhibitor. Out of 239 betalactamases negative isolates, 38 strains were positive for inhibitor activity. All the isolates from these sources are sensitive to meropenem by disk diffusion and broth dilution method. Our data shows that carbapenemase-producing clinical isolates were found to be harbors with different underlying resistance mechanisms such as betalactamases production, outer membrane porin and efflux pump activity. The emergence of NDM -1 with loss of outer membrane porin was highlighted in this study.


Dr. S. Sujatha, Professor, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry

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