Abstract
Purpose: Antimicrobial resistance and virulence genes play important roles in increasing the severity of Pseudomonas aeruginosa infections, especially in hospitalized patients with high antibiotic pressure. Most genes that encode Pseudomonas aeruginosa virulence factors are controlled and regulated by the quorum sensing (QS) system. The aim of this study was to investigate the frequency of some virulence genes (rhlR, rhlI, lasR, lasI, lasB, toxA, aprA, algD, ExoS, and plcH genes) and their association with antibiotic resistance. Methods: Antimicrobial susceptibility was determined by Kirby-Bauer agar disk diffusion method. A total of 125 clinical isolates of P. aeruginosa were tested for some virulence genes using polymerase chain reaction (PCR). Results: The highest resistance was observed against cefepime (92.8%). Multi-drug resistant (MDR) P. aeruginosa represented 63.2% of total isolates with high distribution among wound isolates (21/79, 26.3% of MDR isolates). LasB was the most prevalent virulence gene among the tested isolates (89.6%) followed by aprA (85.6%), exoS (84%), algD (80%), toxA (76.8%), and plcH (75.2). Furthermore, a significant association (P < 0.05) among most of the tested virulence genes and MDR isolates was found. The presence of more than 5 virulence genes was highly observed among wound infections, otitis media, and respiratory tract infection isolates. Conclusion: The complex association of virulence genes including QS system regulating genes with antibiotic resistance indicates the importance of the tested factors in the progression of infections, which is considered a great challenge for the health-care team with the need for specific studies for each area having different antibiotic resistance profiles and the development of effective treatment strategies such as anti-virulent and quorum sensing inhibiting drugs against P. aeruginosa infections.