Authors: Vedavati B. I, Halesh L.H, Mallikarjun Koppad
Introduction: Infections due to Gram-negative bacilli are increasing worldwide. The extended spectrum β-lactamases (ESBLs), AmpC β- lactamases and metallo βlactamases (MBLs), have emerged as a cause of antibacterial resistance in Gram negative bacteria (GNB). β-lactamase producing GNB presents significant diagnostic and therapeutic challenge in the management of infection. So the present study was conducted to know the antibiogram of Gram negative bacterial isolates, to detect the different β-lactamases and their co-existence, to guide clinician to start appropriate antibiotic therapy for the management of infection. Materials and Methods: A total of 150 Gram negative clinical isolates were identified and antibiotic susceptibility testing was done according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Detection of ESBL was done by the combined disk diffusion method as per CLSI guidelines. Detection of AmpC β lactamase was done by phenyl boronic acid test. MBL was detected using EDTA disc potentiation test. Result: Among 150 Gram negative bacteria studied, 26(17.34%) were pure ESBL producer, 50(33.34%) were pure AmpC producer. ESBL and AmpC co-existed in 16(10.67%) isolates and AmpC and MBL co-occured in 16(10.67%) isolates. Conclusion: Along with routine antibiotic sensitivity testing, special tests should be done to detect “hidden” resistance mechanisms for the effective management of infection. Keywords: Antibiogram, β-lactamases, Extended spectrum β-lactamases (ESBLs), AmpCβ-lactamases, Metalloβ-lactamases (MBLs), Co-existence.
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