Pseudomonas aeruginosa auto inducer3-oxo-C 12 -HSL exerts bacteriostatic effect and inhibits Staphylococcus epidermidis biofilm.

Pseudomonas aeruginosa has evolved the 3-oxo-C12 -HSL and C4 -HSL based quorum sensing system which is responsible for the regulation of various virulence factors and helps to dominates over other bacterial species. Staphylococcus epidermidis has frequently been reported with P. aeruginosa while the role of C4 -HSL and 3-oxo-C12 -HSL on the S. epidermidis had widely been unexplored, and as per our knowledge, this is the first report on the impact of C4 -HSL and 3-oxo-C12 -HSL overS. epidermidis growth and biofilm. We found that among the two AHL molecules; only 3-oxo-C12 -HSL was able to exert a significant effect in all the experiments including growth and biofilm of S. epidermidis. 3-oxo-C12 -HSL at 100 μM and 200 μM concentrations were able to initiate the apparent transient type of planktonic growth inhibition in S. epidermidis. Microscopic analysis and biofilm quantification assay showed the inhibitory effect of 3-oxo-C12 -HSL against S. epidermidis biofilm, initial attachment, and EPS production. The study concludes that P. aeruginosa associated 3-oxo-C12 -HSL exerts the inhibitory effect on S. epidermidis growth and biofilms and thus it may also help Pseudomonasto dominate under the co-infection conditions.