Identification and Isolation of Insertion Sequences, in Carbapenem Resistant Clinical Isolates of Acinetobacter baumannii from Tehran Hospitals

Identification of antibiotic resistance Acinetobacter baumannii can help us control and prevent the infections and reduce the mortality rates caused by this microorganism.
This study aimes to identify the insertion elements that can play important roles in antibiotic resistance in A. baumannii.
A total of 105 A. baumannii isolates from clinical samples were tested for their susceptibility to different antibiotics using disc diffusion test (DDT). Then, the isolates were evaluated for the presence of blaOXA genes along with IS elements by polymerase chain reaction (PCR).
PCR analysis showed that ISAba1 was present in all the isolates while 92.36% of the isolates were positive for ISAba2. All the strains of A. baumannii possessed a blaOXA-51-like gene but blaOXA-58-like gene was absent in all of them. About 64.76% of the isolates were positive for blaOXA-24-like gene and 98.09% were positive for blaOXA-23-like gene. All of the isolates were pandrug resistant A. baumannii and the lowest resistance rates were observed toward minocycline and amikacin (93.33% in both) and trimethoprim/sulfamethoxazole (92.38%).
The high prevalence rates of ISAba1 and ISAba2 among A. baumannii isolates can explain the rapid dissemination of resistance genes. Thus, finding the accessory genes such as IS elements, which can affect antibiotic resistance, should be more considered.