Elevated prevalence of multidrug-resistant Acinetobacter baumannii with extensive genetic diversity in the largest burn centre of northeast Iran.

OBJECTIVES: The emergence and spread of multidrug-resistant (MDR) Acinetobacter baumannii isolates is now frequently associated with nosocomial infections. The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst A. baumannii isolated from a burn centre at a teaching hospital in Iran.

METHODS: A total of 54 A. baumannii isolates were collected from burn wound infections of hospitalised patients. Antimicrobial susceptibility of the isolates was determined, and genotyping analysis was performed by repetitive extragenic palindromic PCR (rep-PCR). PCR assay was performed to investigate the distribution of β-lactamase, aminoglycoside-modifying enzyme and efflux pump genes.

RESULTS: Etest results revealed that the most active antimicrobial agent was colistin (100% susceptibility), followed by tigecycline (96.3%). The blaOXA-51 and blaADC genes were detected in all of the isolates, but blaOXA-58-like was not detected. The prevalence of blaTEM, blaIMP, blaVIM, blaOXA-23-like and blaOXA-24-like genes was 64.8%, 70.4%, 70.4%, 66.7% and 68.5%, respectively. ISAba1 was detected upstream of blaOXA-23-like and blaADC in 66.7% and 77.8% of isolates, respectively. This study showed a high level of distribution of adeB (72.2%), aphA6 (81.5%), aacC1 (85.2%), aadA1 (59.3%), aadB (31.5%), tetB (70.4%) and aphA1 (29.6%) in A. baumannii strains. Based on rep-PCR analysis, four clusters (I-IV) were defined.

CONCLUSIONS: The elevated prevalence of MDR A. baumannii strains in this burn centre suggests that local antibiotic prescription policies should be precisely revised. Moreover, strict infection control procedures to prevent further dissemination need to be prioritised immediately.