The emergence of antibiotic resistance among microorganisms has become a global problem. One of the mechanisms by which bacteria acquire resistance to antimicrobial agents is by the production of enzymes that either destroy or modify the antibiotic before it reaches the target. One among them is metallo beta lactamases (MBL). The importance of NDM-1 gene is that it inactivates all beta lactams except aztreonam. Treatment of multidrug resistant bacteria causes a serious challenge to physicians treating patients in ICUs. A study was conducted in the Dept. of Microbiology, Govt. Medical College, Ernakulam for a period of one year from July 2018 to June 2019. A total number of 200 isolates obtained from clinical samples of patients admitted in different ICUs were included in the study. Out of the 200 isolates, 164 were Gram negative bacteria. Among them 104(52%) were multidrug resistant. The predominant MDR Gram negative isolate was Acinetobacter species (32%) followed by Klebsiella species (29%) and E.coli (26%). Majority of the isolates were obtained from sputum samples (42%). Proportion of metallo beta lactamase production was detected by phenotypic methods such as double disk synergy test and modified Hodge test. Molecular characterization, especially detection of NDM-1 gene was done by RT PCR. NDM-1 gene was detected in 8.5% of the isolates predominantly in Acinetobacter species (58.82%) followed by E.coli (23.5%) and Klebsiella species (17.64%). Among patients who had infection with MDR Gram negative bacteria, 54.8% of the patients improved after appropriate antibiotic therapy. Mortality rate in our study was 41% which is lower than the mortality rate reported by previous studies in India.

Keywords: Gram negative bacteria, multidrug resistant, metallobetalactamase.

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Dr Lancy Justus

Professor of Microbiology, Govt. Medical College, Ernakulam, Kerala, India