Detection of Genetic Supports Regulated the Quorum Sensing in Multidrug-Resistant P. aeruginosa and E. coli

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Résumé

Quorum sensing (QS) is a system of intercellular communication and regulation of the
transcription of resistance, virulence, and pathogenicity genes. The aim of this study was to
identify genetic markers controlling quorum sensing in multidrug-resistant P. aeruginosa and E.
coli. A set of fifty (50) strains, composed of P. aeruginosa (30) and E. coli (20), were isolated
from animal products. These strains underwent phenotypic and biochemical identification.
Antibiotic resistance profiles were determined by the Muller-Hinton agar diffusion method.
Quorum sensing markers (LasI/LasR) and (RhlI/RhlR) were detected by PCR. The prevalence of
the Las gene (LasI/LasR) and the Rhl gene (RhlI/RhlR) was 80% and 60%, respectively, in P.
aeruginosa. In E. coli, the prevalence of QS genes was 40% for Las (LasI/LasR) and 40% for
Rhl (RhlI/RhlR). The total prevalence of the Las gene and the Rhl gene was 64% (LasI/LasR)
and 68% (RhlI/RhlR), respectively, in the studied strains. E. coli strains exhibited penicillin
resistance exceeding 25% for amoxicillin (67.5%), amoxicillin-clavulanic acid (46.6%), and
piperacillin (28.5%). This resistance was less than 25% for ciprofloxacin (23.7%), ceftazidime
(18.6%), cefoxitin (17.8%), cefepime (14.3%), and imipenem (14.6%). P. aeruginosa strains
expressed multidrug resistance to ticarcillin (54%), aztreonam (47%), ticarcillin-clavulanic acid
(32%), piperacillin (29%), levofloxacin (24%), and ciprofloxacin (29%). The detection and
control of genetic factors influencing quorum sensing in multidrug-resistant bacteria can
improve diagnosis and contribute to the fight against biofilm infections.

Mots-clés

Quorum sensing, P. aeruginosa, E. coli, multi resistance, Las gene, Rhl gene