Biofilm Formation, Multidrug Resistance, and Biofilm-Associated Resistance Genes in Clinical <i>Pseudomonas aeruginosa</i> Isolates

Abstract

Background: Pseudomonas aeruginosa is a major cause of hospital-acquired infections owing to its ability to form biofilms and express a range of virulence factors. Objectives: This study investigated the biofilm-forming capacity and resistance genes in clinical P. aeruginosa isolates. Methods: A total of 38 isolates from various clinical sources, including urine, the respiratory tract, blood, wound sites, and sputum, were included in the study. Multidrug resistance profiles, isolate identification, and antimicrobial susceptibility were determined using the BD Phoenix M50 Automated Microbiology System (Becton Dickinson, Franklin Lakes, NJ, USA), and biofilm formation was assessed using a crystal violet assay. In addition, the presence of biofilm-specific antibiotic resistance genes (ndvB, tssC1, PA5033, and PA2070) was evaluated by PCR. Results: Most isolates (97.37%) exhibited biofilm formation at varying levels, whereas only 1 isolate (2.63%) was a non-producer. Moderate and strong biofilm production was observed in most isolates. Most isolates also carried the investigated genes, with detection rates ranging from 89.5% to 94.7%. High rates of multidrug resistance and widespread biofilm formation were observed among the isolates. No statistically significant association was observed between gene presence and the level of biofilm formation. Conclusions: Given the limited sample size (n = 38), sparse phenotypic distribution, and high prevalence of the genes studied, this study was underpowered to draw definitive conclusions about these associations. Further studies incorporating larger cohorts and functional analyses are required to clarify the roles of these genes in biofilm development.