Indian Journal of Science and Technology

Abstract

Objectives: Screening and characterization of Quorum quenching bacteria from different soil and water samples. Methods/ Statistical Analysis: Quorum quenching bacteria were isolated from different soil and water samples by enrichment culture technique using minimal medium with AHL as sole source of carbon. The bacteria isolated were subjected to bioassay by using Chromobacterium violaceum (CV026) as bio indicator organism. Bacteria exhibiting quorum quenching activity were subjected to 16s r RNA analysis. Quorum quenching activity was further confirmed by subjecting samples to LCMS analysis. Findings: Of all the samples tested only six bacteria exhibited quorum quenching activity which was tested by using bio indicator strain Chromobacterium violaceum (CV026). To confirm the activity all the six samples were subjected to LCMS analysis. Maximum peak was observed at retention time of 4.43 with pure C6 AHL purchased from sigma Aldrich. These samples do not have any characteristic C6 AHL peak in LCMS analysis. This finding confirms the inactivation of AHL which may be enzymatic either by lactonases or acylases. Molecular characterization was done by 16 s rRNA sequencing for one isolate, identified as Enterobacter sp. and designated as Enterobacter sp. EYAR1. Applications: Quorum quenching enzymes help in reducing the development of antibiotic resistance in clinical pathogens by inactivating quorum sensing circuit expression of virulence genes, hence they can be explored as an alternative strategy in controlling infections.

Keywords: Chromobacterium violaceum (CV026), Enterobacter sp. EYAR1, Lactonases, Quorum Quenching, Quorum Sensing