Molecular Characterization of Metallo Beta Lactamase Producing Clinical Isolates of Acinetobacter

Introduction: Metallo-beta-lactamase (MBL)-producing Acinetobacter is a therapeutic challenege all over the world. The aims of this study were to determine the prevalence of MBL genes and evaluate the antimicrobial susceptibility profile of carbapenem non-susceptible isolates of Acinetobacter. Material and Method: During a period of 12 months (November 2012 to October 2013) 94 isolates of carbapenem non susceptible Acinetobacter were collected from different clinical specimens. All isolates were tested for antimicrobial susceptibility by Kirby-Bauer disk diffusion method. Carbapenem non-susceptible isolates were further screened for production of MBL by DDST, CDT with Imipenem, Meropenem and EDTA,Etest and were then subjected to PCR for detection of MBL genes. Result: Among 94 Carbapenem (resistant to either or both Imipenem and Meropenem) non-susceptible isolates of Acinetobacter 25 (26.59%) were found to be MBL producers. Of 25 MBL-producing isolates, 24% carried the bla(IMP) gene and 76% carried the bla(VIM) gene. All MBL-producing isolates were multidrug resistant. Conclusion: Our study was intended to find out the prevalence of MBL in Acinetobacter (26.59% of total carbapenem resistant isolates). All the MBL producing isolates were resistant to almost all the group of drugs except Tigecycline(100% sensitivity).This indicate that generally MBL producing isolates carry multidrug resistant integrons. Hence,identification and AST of MBL producing Acinetobacter is essential for proper prophylaxis.