Detection of metallobetalactamase producing imipenem resistant acinetobacter species in intensive care unit patient in a Tertiary Care Centre

Abstract

Introduction: Metallobetalactamase producing Acinetobacter species has been reported to be an important cause of nosocomial infection and is a critical therapeutic problem worldwide, especially in the intensive care unit. Objectives: To determine the frequency of metallo‐β‐lactamases among imipenem‐resistant Acinetobacter species and to compare different phenotypic methods. Materials and Methods: 59 imipenem‐resistant Acinetobacter species isolated from various clinical samples were tested for metallo‐β‐lactamase production using different phenotypic methods. Minimal Inhibitory Concentratrion (MIC) to meropenem was determined by E test. Results: Of all the imipenem resistant isolates, 50.8% of Acinetobacter species were MBL producers. MIC of all those MBL producing isolates were ? 16?g/ml. Among the Acinetobacter species MBL production were detected in 30 isolates (50.8%) by E test, 29 isolates (49.2%) by CDT and in 15 isolates (25.4%) by DDST and DPT. The sensitivity and specificity of CDT, DDST and DPT compared to E test was 98%, 48.1%, 48.1% and 100%, respectively. Conclusion: Prevalence of MBL producing Acinetobacter species is being increasingly reported in ICU patients. The MIC of all the MBL producing isolates for meropenem were >16?g/ml (Resistant). E test and CDT were more reliable for MBL detection. CDT was cost effective, easy to perform and interpretation also straightforward. MBL producing isolates were multidrug resistant making therapeutic choices limited. Continuous antibiotic surveillance, infection control practices and an effective antibiotic policy are required to address the problem of MBL – associated infections. Keywords: Acinetobacter species, MBL detection.