The Prevalence of ISAba1 and ISAba4 in Acinetobacter baumannii Species of Different International Clone Lineages Among Patients With Burning in Tehran, Iran

BACKGROUND Multidrug resistant strains of Acinetobacter baumannii (MDR-AB) have emerged as alarming nosocomial pathogens among patients with burning. OBJECTIVES The current study aimed to determine the susceptibility of A. baumannii species, carbapenems resistance patterns, and their association with IS Aba 1 and IS Aba 4 elements upstream of the bla OXA-like genes, and the distribution of international clone (IC) of A. baumannii isolates among patients with burning in Tehran, Iran. MATERIALS AND METHODS In the current study, 62 A. baumannii species isolates from patients with burning in Tehran, Iran, in 2012 were evaluated for the antimicrobial susceptibility, genetic relationships, ICs, carbapenemase encoding genes, and insertion elements IS Aba upstream of bla OXA-like genes. RESULTS The highest rates of susceptibility were observed with colistin (88.7%) and tigecycline (82.2%). The extensively drug-resistance and pan drug-resistance were observed in 37.1% and 8.1% of the isolates, respectively. About 98.3% of 17 genotypes categorized into three distinct clusters. Thirty-six of the 62 isolates (58%) belonged to the IC II lineage. The most prevalent acquired OXA-type carbapenemase was bla OXA-23-like (62.9%). IS Aba 1 and IS Aba 4 were detected upstream of bla OXA-23-like genes in 45.1% and 12.9% of isolates, respectively. In 32.2% of all isolates, IS Aba 1 laid upstream of bla OXA-51-like genes. The PCR results were negative for carbapenemase genes of Ambler class A and B, except bla VIM-2 . (1.6%). CONCLUSIONS It was the first study that attempted to detect the insertion elements IS Aba and IC lineages in MDR-AB species isolated from patients with burning in Iran.