Insight into quorum sensing genes LasR and RhlR, their related virulence factors and antibiotic resistance pattern in Pseudomonas aeruginosa isolated from ocular Infections

Document Type : Original Article


1 Department of Medical Microbiology and Immunology, Faculty of Medicine, Tanta University, Egypt

2 Department of Ophthalmology, faculty of medicine, Tanta University, Egypt


Background:  Pseudomonas aeruginosa can cause several ocular infections that are associated with adverse outcomes, owing to the production of different virulence factors that are regulated by quorum-sensing (QS) mechanisms. The current study aims to detect different QS dependent virulence factors, antibiotic resistance patterns in P. aeruginosa associated with ocular infections to correlate them with QS genes and to assess their impact on visual outcome. Methods: several ocular specimens were collectedfor isolation ofP. aeruginosa. Antibiotic susceptibility was evaluated. The presence of QS genes (rhlR and lasR) was identifiedby PCR. The isolates were assessed for their capability to produce virulence factors such as pyocyanin, protease, twitching motility, exopolysaccharides, and biofilm. Results: Out of 55 P. aeruginosa isolates, 38.2% were MDR, 29.1% were XDR, and 12.7% were PDR. The highest sensitivity was to meropenem 67.3% while the lowest sensitivity was to ceftazidime18.2%. The frequency of studied virulence factors, exopolysaccharides production, biofilm formation, twitching motility, protease, and pyocyanin production was 94.5%, 89.1%, 83.6%, 81.8%, and 78.2% respectively. Quorum-sensing genes lasR and rhlR were identified in 89% and 81.8% of the isolates respectively. The assessed virulence factors and antibiotic resistance pattern were significantly correlated with the presence of QS system. Conclusion: This study emphasized the importance of the QS system in regulating the formation of virulence factors and antimicrobial resistance in P. aeruginosa. Consequently, anti-QS and anti-virulence therapy can be a promising substitute to antibiotic therapy currently available.


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