Phenotypic Methods for the Detection of Various Betalactamases in Carbapenem Resistant Isolates of Acinetobacter baumanii at a Tertiary Care Hospital in South India

Purpose of the Study: The purpose of this study was to evaluate the production of various beta lactamases among multi-drug resistant Acinetobacter baumanii isolates from clinical specimens. Methods Used: A total of 100 Acinetobacter baumannii meropenem resistant isolates were used for the detection of carbapenemases (Modified Hodge test), AmpC beta lactamase (the AmpC disc test) and metallo beta lactamase (the Disc potentiation test). Results and Conclusion: Among 100 meropenem resistant isolates, 20% were carbapenemase producers, 73% were AmpC producers, and 10% were metallo beta lactamase producers. MBL production, AmpC beta lactamase production and carbapenemase production is becoming common in the multi drug resistant isolates of A. baumannii. Our study suggests that the disc potentiation test, the Amp C disc test, and the Modified Hodge test are simple tests that can be done routinely in the lab for all the multi drug resistant isolates of A. baumannii.