Prevalence of Quorum Sensing Regulator/ Autoinducer Synthase (abaR/abaL) genes among the Multi-drug resistant strains of Acinetobacter baumannii: A Cross-sectional Study

Introduction: Acinetobacter baumannii (A. baumannii) is a significant Multi Drug Resistant (MDR) opportunistic pathogen, documented as a priority pathogen due to its persistence in hospital environments and its ability to cause nosocomial infections. Aim: To investigate the prevalence of Quorum Sensing (QS) mediating abaR/abaL genetic determinants in MDR strains of A. baumannii isolated from wound infections. Materials and Methods: This cross-sectional study was conducted in the department of Microbiology, at Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Institute (SIMATS), Chennai, Tamil Nadu, India, from January to April 2024. A total of 20 clinical isolates of A. baumannii were obtained from patients with deep wound infections. The isolates were identified using the VITEK 2 system, and their antibiotic susceptibility profiles were evaluated. Biofilm formation was assessed using a microtiter plate assay, while abaR/abaL genes were detected via Polymerase Chain Reaction (PCR). Mutations were identified through Sanger sequencing. Fisher’s exact test was performed in Statistical Package for the Social Sciences (SPSS) with p<0.05 considered statistically significant. Results: A total of 20 isolates were identified as A. baumannii using the VITEK 2 system followed by their antibiotic susceptibility profiles. The findings revealed that antibiotic susceptibility testing indicated high resistance rates to common antibiotics, with complete susceptibility to tigecycline and colistin. Sixty percent of the isolates demonstrated strong biofilm-forming capabilities, and 100% of the isolates acquired the abaL gene, while 90% possessed the abaR gene. Sequence analysis showed significant genetic variability in both genes, with several mutations potentially linked to enhanced resistance and virulence. Conclusion: This study highlights the relationship between QS systems, biofilm formation, and antibiotic resistance, emphasising the importance of targeting the QS pathways as a novel therapeutic approach for controlling MDR A. baumannii infections. Further investigations into the molecular mechanisms underlying QS regulation are essential for developing effective antimicrobial strategies against this formidable pathogen.