Anti-infective potential of plant-derived quorum sensing inhibitors against multi-drug resistant human and aquatic bacterial pathogens

The present study intended to decipher the anti-infective potential of bioactive phytocompounds, such as rosmarinic acid, morin, naringin, chlorogenic acid, and mangiferin, against aquatic and human bacterial pathogens using Artemia spp. nauplii and Caenorhabditis elegans as animal models, respectively. Initially, the test compounds were screened against the QS traits in Vibrio spp., such as bioluminescence production and biofilm formation. The test compounds effectively inhibited the bioluminescence in V. harveyi. Further, the confocal laser scanning microscopic analysis revealed that these natural compounds could efficiently reduce the clumping morphology, a characteristic biofilm formation in Vibrio spp., without inhibiting bacterial growth. The results of in vivo analysis showed a significant increase in the survival of Artemia spp. nauplii infected with Vibrio spp. upon exposure to these compounds. Moreover, the compounds used in this study were already proven and reported for their quorum sensing inhibitory efficacy against Pseudomonas aeruginosa. Hence, the anti-infective efficacy of these compounds against P. aeruginosa (PAO1) and its clinical isolates (AS1 and AS2) was studied using C. elegans as a live animal model system. The results of time-killing assay deciphered that rosmarinic acid and naringin are being the most effective ones in rescuing the animals from P. aeruginosa infection followed by morin, mangiferin, and chlorogenic acid. Further, the toxicity results revealed that these compounds did not show any lethal effect on C. elegans and Artemia spp. nauplii at the tested concentrations. In conclusion, the phytochemicals used in this study were effective in controlling the QS-regulated virulence traits in Vibrio spp. and P. aeruginosa infections in Artemia spp. nauplii and C. elegans animal model systems, respectively.