Abstract

Carbapenem-resistant Acinetobacter baumannii (CRAB) has become a significant pathogen responsible for severe healthcare-associated infections, exhibiting extensive antimicrobial resistance and being associated with elevated mortality rates. Although numerous studies have investigated carbapenemase-encoding genes, data are limited on the correlation between genotypic profiles and carbapenem-resistant phenotypes in CRAB. A cross-sectional descriptive study was conducted on CRAB. The study aimed to investigate the distribution patterns of carbapenemase genotypes and carbapenem-resistant phenotypes of CRAB isolates and to assess the correlation between genotypic and phenotypic characteristics. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method., and carbapenemase genes were detected by multiplex real-time PCR. Among the 139 CRAB strains included in the study (strains resistant to either imipenem or meropenem), the imipenem-resistant (R)–meropenem-resistant (R) phenotype was predominant, accounting for 90.6%, and 100% of the strains were detected with carbapenemase-encoding genes. While the single gene NDM–1 was detected in only 3.6% of isolates, the majority involved gene combinations, with the gene combination of OXA–51 and OXA–23 being the most prevalent (68.3%). The rates of individual genes (single or in combination) were: OXA–51 (90.6%), OXA–23 (79.9%), NDM–1 (28.1%), OXA–58 (12.9%) and IMP (0.72%); no VIM and KPC genes were detected. In conclusion, the majority of CRAB strains in this study exhibit complete resistance to carbapenems (R-R phenotype) and carry multiple carbapenemase-encoding genes simultaneously, with the OXA–51 and OXA–23 gene combination being the most common. The relationship observed between the phenotypes imipenem (R)–meropenem (R) and imipenem (I)–meropenem (R) in the OXA–58 and NDM–1 gene combination was statistically significant.