Phenotypic and genotypic detection of metallo-β-lactamases in A. baumanii isolates obtained from clinical samples in Shahrekord, southwest Iran
Abstract Objective: Acinetobacter baumanii is a pathogenic bacterium that is the cause of many nosocomial infections. This study aimed to determine metallo-β-lactamases (MBL) produced by the A . baumanii isolated obtained from clinical samples in Shahrekord, southwest Iran . Results: A total of 100 A . baumanii isolates were isolated from 250 clinical samples between June 2013 and June 2014. Then, the isolates were identified by biochemical tests and MBL screening conducted by the phenotypic tests modified Hodge, EDTA-disk synergy (EDS), combined disk (CD) and AmpC disc after antibiotic sensitivity test, and the bla genes detected by PCR. Eighty-five (85%) isolates were resistant to meropenem and imipenem. Phenotypic tests showed that out of the 100 isolates, 46, 59, 50, 65 and 65 isolates were positive: AmpC disk, CD, EDS, Modified Hodge and Etest MBL, suggesting MBL production, respectively. Gene detection by PCR showed that 23 isolates carried the VIM-1 gene and only three isolates carried the IMP-1 gene. The prevalence of metallo-β-lactamases-containing A . baumanii isolates is increasing, and the coexistence of various carbapenemases is a problem. Continuous monitoring of the infections due to these bacteria should be taken into account in planning for alternative and new therapeutic strategies.