Detection of multidrug-resistant Acinetobacter baumannii from burn patients and healthcare workers in Iran

Multidrug-resistant (MDR) Acinetobacter baumannii is a serious global health threat. Burn patients are at high risk to acquire A. baumannii infections from endogenous sources. This study evaluated carbapenem resistance and clonal relatedness of A. baumannii isolated from burn patients and healthcare workers (HCWs).The study was performed in 100 non-duplicated A. baumannii isolates from nasal and hand samples of hospitalized burn patients and HCWs in two hospitals of Iran from June 2020 to August 2021. Antimicrobial susceptibility testing was performed and carbapenemase genes were detected by PCR. Clonal relatedness of A. baumannii isolates was determined by two single-locus sequence-based typing of blaOXA-51-like and ampC and by multilocus sequence typing (MLST).All A. baumannii isolates were found to be MDR while susceptible to colistin. The intI1, conserved segments of class 1 integron (intI1 CS), blaIMP, blaVIM, blaOXA-51-like, and blaOXA-23-like, genes were detected in 32.5%, 29.1%, 36%, 95.3%, 100%, 100%; and 14.3%, 14.3%, 21.4%, 92.9%, 100%, and 85.7% of isolates from patients and from healthcare workers, respectively. The blaOXA-58, and blaOXA-143 were not detected among the isolates. Using dual-locus blaOXA-51-like and ampC sequence-based typing (SBT), the isolates obtained from nasal samples of burn patients were grouped into 3 clusters including blaOXA-317, blaADC-88 (72.1%); blaOXA-64, ampC-25 (18.6%); and blaOXA-69, ampC-1 (9.3%). While only allele type blaOXA-317, blaADC-88 was determined among isolates from HCWs. MLST results showed A. baumannii ST136, ST25, and ST1 from burn patients. However, A. baumannii strains from HCWs belonged to ST136. Our findings indicate high prevalence of globally spreading of MDR A. baumannii ST136 carrying blaOXA-23-like from nasal and hand samples of burn patients and HCWs.