Virulence Molecular Epidemiology of Clinical Carbapenem-Resistant Acinetobacter baumannii: A Report from Jordan

Background and Aims: Carbapenem-resistant Acinetobacter baumannii (CRAB) is an opportunistic Gram-negative pathogen that plays a significant role in healthcare-associated infections, leading to severe health complications. While numerous studies have focused on the antibiotic-resistance epidemiology of A. baumannii, fewer have investigated its molecular virulence epidemiology. This study aimed to explore CRAB virulence genes, their biofilm-forming capabilities, and the correlation between biofilm formation and both biofilm-associated virulence genes and carbapenemase-encoding resistance genes.
Materials and Methods: A total of 110 CRAB clinical isolates were collected from two hospitals in Jordan between 2018 and 2019. These isolates were screened for at least seven virulence genes using polymerase chain reaction, and biofilm formation ability was evaluated using the microtiter plate method.
Results: the prevalence of the bap, OmpA, surA, PLD, paaE, basD, and traT virulence genes was 99.1%, 98.2%, 98.2%, 95.5%, 89.1%, 86.4%, and 8.2%, respectively. Overall, 86.4% of the isolates demonstrated biofilm-forming ability, classified as weak (28.2%), moderate (36.4%) and strong (21.8%). No statistically significant correlation was observed between biofilm production and the presence of bap, OmpA, or the carbapenemase-encoding gene (VIM gene). However, a significant relationship was identified between the carbapenemase-encoding gene (OXA-23 gene) and biofilm production.
Conclusions: CRAB infections pose a substantial threat in healthcare settings. This study underscores the critical need to enhance infection control measures in healthcare facilities to prevent CRAB outbreaks. To our knowledge, this is the first study in Jordan to examine the prevalence of virulence genes among clinical CRAB isolates.