EVALUATION OF ANTI-QUORUM SENSING ACTIVITY OF-HEXADECANOIC ACID PRODUCED BY PSEUDOMONAS STUTZERI SJ4 – A MARINE EPIBIOTIC BACTERIUM

Quorum sensing (QS) mechanism is cell communication that plays vital role in the development of infection by many pathogenic microorganisms. It controls multiple virulence factors such as pigmentation, biofilm formation, swarming motility, resistance towards antibiotics, extracellular polysaccharide production (EPS) and expression of several collective traits. The disruption of quorum sensing mechanism can be a solution to the emerging problem of multi-drug resistance among pathogenic bacteria. The effector molecule for Quorum sensing inhibition may be enzymatic or non- enzymatic in nature termed as Quorum Quenching (QQ) or Quorum sensing inhibitory (QSIs)/anti –QS compound, respectively. We used marine epibiotic bacteria as a source to obtained novel bacterial strain as QSI producer. One of the potent isolate, SJ4 was identified as Pseudomonas stutzeri SJ4, it is a short rod, gram negative bacterium. The ethyl acetate extract from P. stutzeri SJ4, showed highest QSI activity against monitor strain Chromobacterium violaceum (MTCC 5526). The extracted compound was tested against P. aeruginosa PAO1 at minimum inhibitiory concentration (MIC) and sub-MIC to study the effect on virulence factors. The significant inhibition of pycocyanin pigment, EPS production, rhamnolipid production and reduced swimming and swarming motility was observed. In addition, biofilm formation was notably inhibited which was confirmed by staining and spectometric method. Based on this observation, QS interption by extract which contain QSI remarkebly reduced the virulence of pathogen hence, can be use as therapeutic agents. The Thin Layer Chomatography (TLC) and Gas chrmoatography-Mass Spectrometry (GC-MS) identified major compound as n-Hexadecanoic acid. However, further research is required on purification of compound and its potential applications for the treatement of infections.