Molecular investigation of integron types and imipenem-resistance encoded genes in Acinetobacter baumannii strains isolated from burns patients in Iran

Abstract

Acinetobacter baumannii is commonly distributed as a significant opportunistic pathogen, particularly in burn cases, all over the world. The purpose of this research was the molecular identification of imipenem-resistant A. baumannii isolated from burns patients in a Motahari hospital in Tehran, Iran. In a 9-month period, 173 A. baumannii isolates were obtained from burns cases subjected to the Motahari Burn Center, Tehran, Iran. The resistance pattern of several antibiotics was evaluated. Metallo-β-lactamase (MBL)-producing isolates were detected by double-disk synergy and an MBL E-test. Polymerase chain reaction (PCR) was conducted to detection following β-lactamase genes: blaIMP, blaVIM, blaSIM, blaGIM, blaSPM, blaAIM, blaNDM, blaDIM, blaKPC, blaOXA-23/24/51, and blaOXA-58. The integron classes (I, II and III) were recognized using PCR. Out of the 173 tested isolates, 79.7% and 22.5% of the strains were multi drug-resistant (MDR) and extensively drug-resistant (XDR), respectively. The rate of resistance to imipenem was 87.3%. Based on double disk synergy and E-test, 87.4% and 62.3% of the isolates, were MBL-producing isolates respectively. The frequency of blaOXA-23 and blaOXA-24 were 74.2% and 32.5%, respectively. Our results showed 58.9%, 43%, and 1.3% of the strains were positive for blaVIM, blaIMP and blaNDM genes, respectively. Furthermore, 32.5%, 66%, and 1.5% of strains harbored intI, intII, and intIII genes, respectively. The increasing frequency of carbapenem-resistant A. baumannii in burns patients emphasizes the essential of infection management measures, including antibiotic susceptibility patterns and prompt detection of beta-lactamase-producing strains.