Relation between Biofilm Formation, Quorum Sensing Genes (Rh1I-LasI) and Carbapenem Resistance Among Pseudomonas Aeruginosa Clinical Isolates

Background: Biofilm has a vital role in the pathogenesis of P. aeruginosa infections that represent a major challenge for antimicrobial therapy. Objectives: This study was set out to investigate biofilm formation ability and its quantification in relation to the presence of Rh1I and lasI quorum sensing genes among P. aeruginosa clinical isolates. Furthermore, possible association between biofilm occurrence and carbapenemase activity was analyzed. Methodology: 62 P. aeruginosa isolates from different clinical specimens were isolated and investigated for biofilm formation by tissue culture plate method (TCP) and PCR (RhI1 and LasI QS genes). Carbapenemase activity was also detected by Carba NP test and confirmed by PCR (IMP and VIM MβL genes). Results: Most of P. aeruginosa C.I.s (70.9%) were biofilm producers by TCP. The quorum sensing Rh1I and LasI genes were present in 67.7% and 48.4% of the isolates respectively. By Carba NP test, 64.5% of P. aeruginosa C.I.s were carbapenemase producers where each IMP and VIM gene presented alone in 33.9% and 24.2 % of the C.I.s respectively. Conclusion: There was a high tendency for biofilm formation by P. aeruginosa C.I.s that increased by the presence of QS. Non- significant relation between biofilm formation and carbapenem resistance.