Antibiotic sensitivity and genotyping of Acinetobacter baumannii isolated from clinical and environmental samples of burn hospital of Tehran using MLVA method

Acinetobacter baumannii has emerged as an important hospital pathogen worldwide especially in the burn ward. The aim of this study is to determine the pattern of antibiotic susceptibility and genotyping of A. baumannii isolated from clinical and environmental samples of Shahid Motahari hospital in Tehran using MLVA method. In this study, ۱۷۳ clinical and ۲۸ environmental isolates of A. baumannii were collected from Shahid Motahari hospital within a ۹-month period (۲۰۱۸-۲۰۱۹). The isolates were confirmed by biochemical and molecular tests with OXA-۵۱ primer. Antibiotic sensitivity was performed by the disc diffusion method according CLSI M۱۰۰-S۲۱ guidelines. MLVA-PCR was performed with six STR markers including Abaum-۳۵۳۰, Abaum-۳۰۰۲, Abaum-۲۲۴۰, Abaum-۱۹۸۸, Abaum-۸۲۶, and Abaum-۲۳۹۶. Out of ۲۰۱ tested strains for antibiotic sensitivity, ۱۲۷ (۶۳.۲%) and ۳۵ (۱۷.۵%) of isolates of the strains were multidrug-resistant (MDR) and extensively drug-resistant (XRD). Microsatellite typing of ۲۰۱ A. baumannii isolates showed ۱۹۷ genotypes in four clusters. The Hunter-Gaston diversity index (HGDI) of six markers (STRs) for all isolates was ۰.۹۱۶۹. The progressive increase in A. baumannii infections and antibiotic resistance in hospitals demands some measures for rapid description of the typing of isolates and identification of sources of infection. Our results indicated that MLVA a method based on PCR was more effective for typing of clinical and environmental strains of A. baumannii. These findings highlight the importance of international resistance against different antibiotics as well as molecular epidemiological control of A. baumannii isolates with XDR and MDR characteristics.