A Study On Metallo-Beta Lactamase Producing Pseudomonas Aeruginosa Species In Clinical Isolates Of A Tertiary Care Hospital Of Bihar

Introduction: Metallo-beta lactamase production is the most common mechanism of carbapenem resistance. Metallo-beta lactamase is a zinc dependent enzyme belonging to Ambler class B that can hydrolyse all beta lactam antibiotics including carbapenem. Keeping it in mind we have conducted a research to find out MBL positivity rate in clinical isolates of Pseudomonas in a tertiary care hospital of Bihar. Methodology: This is a descriptive cross-sectional study conducted in the Department of Microbiology, Jawaharlal Nehru Medical College and Hospital, Bhagalpur, Bihar, India over a period of 1 year from May 2020 to April 2021. Depending upon site of infection samples were collected like urine, pus, sputum, BAL, ear swab etc in sterile container. Carbapenem resistance was suspected when either imipenem or meropenem was resistant (mic>8 μl/ml).MBL production was tested in all carbapenem resistant Pseudomonas species by Combined disc test with imipenem and was confirmed by MBL- E test. Results: A total of 1357 various body fluids were obtained from various wards of the hospital over the study period, out of which, Pseudomonas species were isolated from 207 samples. Among 207 samples, 181 were P. aeruginosa and 26 were P. putida. Majority of the samples were obtained from OPD followed by IPD and ICU. MBL production (MBL +) was noted among 13.5% (28/207) of isolates and carbapenem resistance was observed among 14.9% (31/207). When both these characters were matched, it was noted that almost two-third (74.2%) of carbapenem resistance (CR) Pseudomonas were MBL positive. Both these characteristics were more common among p. putida as compared with P. aeruginosa. Conclusion: MBL producing Pseudomonas is difficult to treat but easy to prevent by proper hospital infection control measures and antibiotic policy