Evaluation of Antimicrobial Resistance and Frequency of <i>bap</i> Gene Among <i>Acinetobacter baumannii</i> Strains Isolated from Hospitalized Patients

Background: Acinetobacter baumannii has emerged as a major cause of hospital-acquired infections, posing a significant threat, especially in critical care environments, with mortality rates reaching up to 35%. Its ability to form biofilm on various surfaces within healthcare settings further facilitates the transmission of infections, raising growing concerns. This study was designed to evaluate antimicrobial resistance and the frequency of bap gene among A. baumannii collected from hospitalized patients in Mazandaran Province. Methods: This cross-sectional study was conducted on 100 clinical isolates of A. baumannii recovered from hospitalized patients. In accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines, the antibiotic susceptibility profiles of the isolates were evaluated using the disk diffusion method. For colistin, the minimum inhibitory concentration (MIC) was determined by the broth microdilution method. The presence of the bap gene was assessed using conventional polymerase chain reaction (PCR). Results: The findings revealed that A. baumannii strains demonstrated high resistance to several antibiotics, particularly carbapenems and cephalosporins, with limited effective treatment options. Notably, colistin, tobramycin, and gentamicin remained effective against these isolates. Importantly, the bap gene was detected in all A. baumannii isolates, highlighting its widespread prevalence. Conclusion: This study highlights the substantial burden A. baumannii imposes on healthcare systems and patients due to its multidrug-resistant nature. The continued effectiveness of colistin, tobramycin, and gentamicin suggests the need to reconsider reliance on traditional antibiotics such as carbapenems. The prevalence of the bap gene underscores the urgency of addressing this virulent pathogen. These findings provide valuable insights for local healthcare strategies to combat A. baumannii infections and ultimately improve patient outcomes.