Sub-minimum inhibitory concentrations of biocides induced biofilm formation in Pseudomonas aeruginosa

It is clear that biofilm formation causes many serious health-care problems. Interestingly, sub minimum inhibitory concentrations (sub-MICs) of some biocides can induce biofilm formation in bacteria. We investigated whether sub-MICs of Savlon, chlorhexidine and deconex®, as biocidal products, can induce biofilm formation in clinical isolates of Pseudomonas aeruginosa. To determine MICs and biofilm formation, we performed microtitre plate assays. All three biocides induced biofilm formation at sub-MICs; Savlon was the most successful antiseptic agent to induce biofilm formation among P. aeruginosa isolates. Deconex had the best inhibition effect on planktonic cultures of P. aeruginosa isolates. We concluded that sub-MICs of Savlon and deconex could significantly induce biofilm formation.