Determination of biofilm formation, antibiotic susceptibility profiles and quorum sensing mediated virulence factors in ceftazidime resistant Pseudomonas aeruginosa

Abstract

This study aims to investigate the relationship between the antibiotic resistance, biofilm production, virulence factors, and quorum sensing systems of Pseudomonas aeruginosa. First, disc diffusion and microdilution tests were applied to determine the antibiotic susceptibility of isolates. Second, virulence factors of isolates were determined phenotypically. Then, intact and internal lasI, lasR, rhII, and rhIR gene regions were amplified by polymerase chain reaction. Finally, biofilm formed by isolates were observed using a confocal laser scanning microscope. As a result, significant differences were found between hospital services and antibiotic resistance (p < 0.05). Biofilm formation was observed in 76% of the isolates. The production of homoserine lactone, pyocyanin, and elastase were detected in 51%, 65%, 66% of isolates, respectively. The lasI gene was 96% intact and 95% internal, and the lasR was 91% intact and 95% internal for the las system. The rhlI was 91% intact and 90% internal, and the rhlR was 80% intact and 90% internal for the rhl system. According to the microscope results, the isolates with antibiotic resistance formed thicker biofilm layer. Biofilm-positive strains were capable of important virulence factors and developed antibiotic resistance, playing a role in the pathogenesis.