Antimicrobial susceptibility patterns and distribution of BlaAXA genes among Acinetobacter spp. isolated from patients at Tehran hospitals

Multiple drug-resistant strains of Acinetobacter have created therapeutic problems worldwide. This study was conducted to determine the antimicrobial susceptibility patterns and prevalence of blaOXA-type carbapenemases among isolates of Acinetobacter spp. obtained from Iranian patients. Here, 128 Acinetobacter isolates were identified at the species level, and their susceptibilities to different antibiotics were determined using disk agar diffusion testing. Isolates were then subjected to multiplex-PCR targeting blaOXA genes. More than 50 of the isolates showed multidrug resistance to different antibiotics. The rates of susceptibility to imipenem, meropenem, piperacillin-tazobactam, and amikacin were 50.7, 50, 42.1, and 38.2, respectively. The MICs of carbapenems for the resistant isolates ranged from 64 to ≥256 μg/ml. All strains of Acinetobacter baumannii possessed a blaOXA-51-like gene. The co-existence of blaOXA-51-like/blaOXA-23-like and blaOXA-51-like/blaOXA-24-like was detected in 25 (n = 32) and 17.9 (n = 23) of the isolates, respectively. Over 70 of carbapenem-resistant strains contained at least two genes encoding OXA-type carbapenemase. Resistance to carbapenems in the population of Acinetobacter strains in Iran is high, with the majority of isolates showing multidrug resistance. A wide diversity of OXA genes exists among the strains of A. baumannii in Iran. Detection of blaOXA-51-like can be used as a simple and reliable method to differentiate A. baumannii strains from other species