Molecular characterization of PGA gene types A–D among multi-drug resistant strains of Acinetobacter baumannii

This study aimed to explore the prevalence of Acinetobacter baumannii in clinical settings, its antimicrobial resistance, and biofilm formation ability in ventilator-associated pneumonia (VAP) patients, with a particular focus on the pgaABCD gene locus responsible for biofilm formation. A total of 53 isolates were collected over a 5-month period from patients suffering from pneumonia and lower respiratory tract infections. The isolates were identified, and their drug resistance profiles were evaluated using the VITEK automated system. Biofilm formation ability was assessed using the crystal violet assay. The presence of the pgaABCD gene was confirmed through PCR, and the sequences were analyzed to investigate gene prevalence and mutations. Among the 53 clinical samples, 29 isolates (54.7%) were confirmed as A. baumannii. Biofilm formation was detected in 62.1% of the isolates, with varying levels of biofilm production. All 29 isolates (100%) encoded both the pgaA and pgaD genes, while the pgaB and pgaC genes were present in 93.10% and 89.66% of the isolates, respectively. Multidrug-resistant (MDR) strains were prevalent among the clinical isolates, with high biofilm production ability. Sequencing of the pgaABCD genes revealed mutations contributing to the diversity of biofilm formation. This study emphasizes the strong relationship between the pgaABCD locus and biofilm formation in MDR A. baumannii strains. The high prevalence of biofilm-forming isolates underscores the challenges in treating infections caused by A. baumannii, especially in VAP patients. These findings highlight the need for biofilm-targeted treatment strategies to improve patient outcomes in healthcare settings.