Chinmayi Joshi, Pooja Patel, Pawan Godatwar, Sanjeev Sharma and Vijay Kothari* Pages 391 - 404 ( 14 )
Background: Antibiotic-resistant members of the family Enterobacteriaceae are among the serious threats to human health globally. This study reports the anti-pathogenic activity of Punica granatum peel extract (PGPE) against a multi-drug resistant, beta-lactamase producing member of this family i.e. Serratia marcescens.Objective: This study aimed at assessing the anti-pathogenic activity of PGPE against the gramnegative bacterial pathogen S. marcescens and identifying the molecular targets of this extract in the test bacterium. Methods: Effect of PGPE on S. marcescens growth and quorum sensing (QS)-regulated pigment production was assessed through broth dilution assay. In vivo anti-infective and prophylactic activity of PGPE was assessed employing the nematode worm Caenorhabditis elegans as a model host. Differential gene expression in PGPE-exposed S. marcescens was studied through a whole transcriptome approach. Results: PGPE was able to modulate QS-regulated pigment production in S. marcescens without exerting any heavy growth-inhibitory effect at concentrations as low as ≥2.5 μg/mL. It could attenuate the virulence of the test bacterium towards the worm host by 22-42% (p≤0.01) at even lower concentrations (≥0.5 μg/mL). PGPE also exerted a post-extract effect on S. marcescens. This extract was found to offer prophylactic benefit too, to the host worm, as PGPE-pre-fed worms scored better (34-51%; p≤0.001) survival in face of subsequent bacterial attack. Differential gene expression analysis revealed that PGPE affected the expression of a total of 66 genes in S. marcescens by ≥1.5 fold. Conclusion: The anti-virulence effect of PGPE against S. marcescens is multifaceted, affecting stress-response machinery, efflux activity, iron homeostasis, and cellular energetics of this bacterium notably. Among the major molecular targets identified in this study are LPS export transporter permease (LptF), t-RNA pseudouridine synthase (TruB), etc.
Antimicrobial Resistance (AMR), Anti-virulence, Microwave Assisted Extraction (MAE), Post Extract Effect (PEE), Prophylaxis, Punica granatum peel, Quorum Sensing (QS), Whole transcriptome analysis (WTA).
Institute of Science, Nirma University, Ahmedabad- 382481, Institute of Science, Nirma University, Ahmedabad- 382481, National Institute of Ayurveda, Jaipur, National Institute of Ayurveda, Jaipur, Institute of Science, Nirma University, Ahmedabad- 382481