Influence of Linoleic Acid on Quorum Sensing in Proteus mirabilis and Serratia marcescens

Quorum sensing (QS) is a bacterial cell density dependent mode of communication involved in regulation of virulence in pathogens including biofilm formation. Accordingly, curbing QS might prove to be an anti-virulence approach of controlling nosocomial infections caused by multi drug resistant bacteria. The report presented here documents the QS inhibitory properties of linoleic acid against Proteus mirabilis and Serratia marcescens known to cause nosocomial infections. Urease assay, prodigiosin assay, protease assay, biofilm formation assay and growth curve analysis were performed to investigate the effectiveness of linoleic acid in controlling virulence of P. mirabilis and S. marcescens. 2.5mM linoleic acid reduced the urease activity and biofilm formation to 42.11% and 11.11% respectively in P. mirabilis; and prodigiosin synthesis, protease activity and biofilm formation to 0%, 65.91% and 33.33% correspondingly in S. marcescens. Therefore, analysis of QS inhibitory behaviour of linoleic acid substantiates its use as a plausible drug for anti-virulence therapy without subjecting the bacteria to discerning force of antibiotics.