Phenotypic detection of MBL, Ampc beta-lactamase and carbapenemases in multi drug resistant isolates ofAcinetobacter baumannii

Abstract

Introduction: Acinetobacter baumannii is one of the major pathogens causing nosocomial infections due to emergence of resistance to various antimicrobial agents. Resistance due to antimicrobial degrading enzymes is now a worldwide problem and a major reason of concern for the treating physicians. Keeping this in mind, the present study was designed to isolate Acinetobacter baumannii and study various antimicrobial resistance mechanisms in them. Materials and methods: A total of 50 A.baumannii isolates from various clinical samples were screened for meropenem resistance for the detection of Carbapenemase and MBL production. Carbapenemase production was confirmed by Modified Hodge Test whereas MBL by Disk Potentiation Test. Cefoxitin resistance was used as a screening test for AmpC beta-lactamase production which was confirmed by AmpC disk test. Results: Maximum isolation of A.baumannii was found in patients admitted in the Intensive care unit with respiratory tract infection. Among the 50 A.baumannii strains, Carbapenemase production was observed in 26.4%, MBL production in 52.9% and AmpC beta lactamase production in 56%. Conclusion: Our study emphasizes on multi-drug resistant A.baumannii highlighting the antibiotic crisis as a result of emergence of various bacteria that show resistance to various antibiotics. Acinetobacter epitomises this trend, as it is an important nosocomial pathogen with a capability of cross-infection particularly in ICUs and a grave limitation of treatment options, thus, requiring an urgent need to control the spread of MDR strains in the hospitals.