Anti quorum sensing potential of probiotics an unexplored strategy against gut derived sepsis caused by Pseudomonas aeruginosa in immunocompromised mice

Abstract

The current study was designed with an aim to investigate the anti-QS potential of probiotic strains and postbiotics against Pseudomonas aeruginosa PAO1. Among the probiotic strains examined, Lactobacillus rhamnosus GG was identified as the most promising candidate. Further investigation confirmed the extracellular and non-enzymatic nature of anti-QS activity. The activity was optimized and bioactive compound in postbiotic of L. rhamnosus GG, responsible for anti-QS potential was extracted, partially purified by analytical and preparative thin layer chromatography (TLC) techniques. Postbiotic derived from L. rhamnosus GG was identified through bio-autography assay and liquid chromatography-mass spectrometry (LC-MS) analysis. Cell free supernatant, crude extract and partially purified postbiotic of L. rhamnosus GG could suppress the virulence factors without affecting growth kinetics of P. aeruginosa. In addition, postbiotic showed its anti-biofilm efficacy and also downregulated the expression of QS associated genes of P. aeruginosa. The results of ex-vivo studies revealed that the postbiotic was non-toxic, hemocompatible, indicating its safe use in further experiments.In-vivo studies demonstrated that L. rhamnosus GG and its postbiotic had remarkable therapeutic efficacy against P. aeruginosa induced gut-derived sepsis in mouse model. Hence, the present study provides insight into anti-QS potential of probiotic bacteria and its postbiotic. This study opens up further avenue to employ postbiotics as anti-virulent agents against P. aeruginosa, especially in gut-derived sepsis but requires clinical validation. newline