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, 173 clinical and 28 environmental isolates of A. baumannii were collected from Shahid Motahari hospital within a 9-month period (2018-2019). The isolates were confirmed by biochemical and molecular tests with OXA-51 primer. Antibiotic sensitivity was performed by the disc diffusion method according CLSI M100-S21 guidelines. MLVA-PCR was performed with six STR markers including Abaum-3530, Abaum-3002, Abaum-2240, Abaum-1988, Abaum-826, and Abaum-2396. Out of 201 tested strains for antibiotic sensitivity, 127 (63.2%) and 35 (17.5%) of isolates of the strains were multidrug-resistant (MDR) and extensively drug-resistant (XRD). Microsatellite typing of 201 A. baumannii isolates showed 197 genotypes in four clusters. The Hunter-Gaston diversity index (HGDI) of six markers (STRs) for all isolates was 0.9169. 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.