Iranian Research Organization for Science and Technology (IROST) Microbiology, Metabolites and Biotechnology 2980-8855 8 1 2025 06 01 Prevalence of bap and ompA immune evasion genes, biofilm formation ability, antibiotic resistance pattern, and motility of Acinetobacter baumannii 1 7 1556 10.22104/mmb.2025.7463.1167 EN Hafez Mozayyan Esfahani Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Babak Beikzadeh Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Soodabeh Rostami Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. Mohammad Rabbani Khorasgani Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran. Journal Article 2025 03 29 Acinetobacter baumannii (A. baumannii) is recognized as a significant pathogen responsible for hospital-acquired infections. This research aims to investigate the frequency of bap and ompA immune evasion genes, thereby determining the profile of antibiotic resistance in bacteria and the biofilm-producing ability among isolates obtained from patients with respiratory infections in Isfahan, Iran. In the present study, among 100 isolates collected from respiratory tract infections, 96 isolates were confirmed as A. baumannii by biochemical tests and molecular analysis. The presence of bap and ompA genes in these isolates was checked by PCR, and antibiotic susceptibility was assessed using the disc diffusion method. Finally, the ability to form biofilm and motility were investigated. Results showed that 100% of the isolates carried the ompA gene. However, for the bap gene, 95.83% of isolates were positive. Investigation of antibiotic resistance showed that A. baumannii isolates exhibited resistance to most antibiotics. The results of the biofilm test revealed that 97.91% of the isolates could form biofilm, including 39.58% with weak biofilm, 44.79% with medium biofilm, and 13.54% with strong biofilm, leaving the remaining 2% unable to form biofilm. Moreover, our results show that 6.4% of isolates were non-motile, 45.9% had an intermediate ability for twitching motility, and 47.7% showed a high ability for twitching motility. No correlation was observed between twitching motility, biofilm production, and antibiotic resistance. The present study demonstrates that the bap and ompA genes are highly abundant in lung infections, and most of these isolates are multidrug-resistant, exhibiting a high ability to form biofilms and display motility.

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