Identification of antibiotic resistance genes in multi-drug resistant Acinetobacter baumannii clinical isolates of Iraqi patients

Acinetobacter baumannii is recognized as a significant healthcare challenge for patients in intensive care units (ICUs) due to its high propensity for multidrug resistance against a wide range of commercially available antibiotics. A total of 150 samples were collected from two distinct hospitals in Erbil city between October and December 2022. Bacterial isolation and identification were primarily carried out using conventional methodologies. Thirty-two isolates were identified as A. baumannii, and their confirmation was achieved using the polymerase chain reaction (PCR) technique. The prevalence of A. baumannii isolates was as follows: 16 (51.6%) in burn samples, 9 (29%) in wound swabs, and 6 (19.3%) in sputum samples. These isolates exhibited high resistance rates against various antibiotics, including rifampin (100%), piperacillin, ceftazidime (93.7%), tetracycline (90.3%), tigecycline, amikacin, levofloxacin, gentamycin, and clarithromycin (87.1%), piperacillin/tazobactam (83.9%), ampicillin/sulbactam, and trimethoprim/ sulfamethoxazole (77.4%), meropenem, and imipenem (74.2%). However, A. baumannii isolates did not exhibit resistance to polymyxin B. Multidrug resistance was detected in 6.25% of the isolates, while extensive drug resistance was observed in 84.37%. Among the A. baumannii isolates resistant to tetracycline, 55% carried the tet(A) gene, while 85% of the isolates harbored the carbapenem resistance gene (blaOXA-51). Furthermore, the qnr gene was found in 65% of the isolates. Polymyxin B was identified as a promising alternative for the treatment of A. baumannii infections.