ANALYSIS OF QUORUM SENSING RELATED GENES IN‎ PSEUDOMONAS AEUROGINOSA ISOLATES FROM CYSTIC FIBROSIS PATIENTS

Background and Aim:Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). The pathogenesis of these infections is multifactorial and the production of many virulence factors is regulated by quorum sensing (QS), a cell-to-cell communication mechanism. QS regulates the production of pathogenic virulence factors and biofilm formation in P. aeruginosa. The four genes lasR, lasI, rhlR and rhlI were found to regulate this QS system. To elucidate the dynamics of P. aeruginosa QS systems during chronic infection of the CF lung, we have investigated QS Genes in isolates obtained from CF patients.Methods:Fourty three P. aeruginosa clinical isolates were collected from 6 months to twelve years old CF patients. QS Genes including lasR, lasI, rhlR and rhlI were amplified by polymerase chain reaction (PCR), and PCR results subsequently underwent sequencing.Results:All of 43 clinical isolates harbored all of quorum‎ sensing related genes including lasR, lasI, rhlR and rhlI genes. Sequence analyses of these isolates showed that 41.66 and 33.33 percent of isolates had point mutations in lasR and lasI genes respectively.Conclusion:These results emphasize the importance of QS genes in establishment and virulence of P. aeruginosa isolates in cystic fibrosis.

Keywords:

pseudomonas aeruginosa , virulence factors , Quorum‎ sensing , cystic fibrosis (CF)