Detection of quorum sensing virulence factor genes and its consanguinity to antibiotic sensitivity profile in the clinical isolates of Pseudomonas aeruginosa.

Abstract

Virulent strains of Pseudomonas aeruginosa exhibit multidrug resistance by intrinsic and extrinsic mechanisms which are regulated by quorum sensing signalling systems. This includes the production of auto-inducers and their transcriptional activators to activate various virulence factors resulting in host infections. The present study is thus aimed to detect the virulence factor production, quorum sensing activity, and susceptibility pattern of P. aeruginosa to antibiotics from clinical specimens. A total of 122 isolates of P. aeruginosa were phenotypically characterized by standard protocols and were categorized into MDR and non-MDR based on the antibiotic susceptibility profiles. Pyocyanin, alkaline protease and elastase production were assessed by qualitative and quantitative methods. Crystal violet assay was carried out for the quantification of biofilms. The genetic determinants of virulence were detected by PCR. Out of the 122 isolates, 80.3% of isolates were MDR and the production of virulence factors was in positive correlation with the presence of genetic determinants and 19.6% were non-MDR, but still showed the production of virulence factors, as confirmed by both phenotypic and genotypic methods. Few carbapenem-resistant strains were detected which did not show the production of virulence factors by both methods. The study concludes, though the strains were non-MDR, they were still capable of producing the virulence factors which may be responsible for the dissemination and chronicity of the infection caused by P. aeruginosa.