Antimicrobial resistance and molecular epidemiology of virulence genes among multi-drug resistant Acinetobacter baumannii clinical isolates in Iran

Multidrug-resistant (MDR) Acinetobacter baumannii ( A. baumannii) is considered a serious threat level bacterial pathogen. This study aims to investigate the prevalence rate of main virulence genes within clinically MDR isolates of A. baumannii and extract their antibiotic susceptibility patterns. In the present study, various clinical specimens were collected from general hospitals of Tehran, Iran in two years. The identification of A. baumannii isolates was performed by conventional biochemical tests. The antibiotic resistance profile of A. baumannii isolates was determined using the disk diffusion method and results were interpreted according to the CLSI guidelines. The existence and frequency of main virulence genes were screened by PCR method in MDR A. baumannii isolates. A total of 198 A. baumannii were isolated from clinical specimens in selected general hospitals in Iran, out of which 90 (45.45%) isolates were recognized as MDR A. baumannii isolates. The highest frequency of MDR A. baumannii isolates was detected in blood (42.22%) and urine (24.44%) specimens, respectively. Moreover, most MDR A. baumannii isolates (43.33%) were isolated from ICU. All of MDR A. baumannii isolates were resistant to piperacillin/tazobactam and cefepime. The prevalence of surveyed virulence genes among MDR A. baumannii isolates was as follows: pld (76.67%), bap (70%), traT (66.67%) lasB (56.67%), omp33-36 (52.22%), and ompA (23.33%). The results of our study revealed that the prevalence of MDR A. baumannii isolates and virulence-associated genes in general hospitals was high. It is suggested that virulence genes were associated with antibiotic resistance in A. baumannii isolates.