Taurine Haloamines and Biofilm. Part I: Antimicrobial Activity of Taurine Bromamine and Chlorhexidine Against Biofilm Forming Pseudomonas aeruginosa

Formation of biofilm is observed in a majority of chronic bacterial skin infections such as non-healing wounds. These infections are persistent as they show increased resistance to antibiotics. Moreover, bacteria hidden in biofilm are protected from the host defence system. It raises serious therapeutic problems in human and veterinary medicine. Therefore, novel anti-biofilm therapeutic strategies should be used. It has been shown in vitro that taurine bromamine (TauBr), the product of reaction between taurine and hypobromous acid (HOBr), exerts anti-microbial properties against planktonic form of various bacteria. Moreover, clinical studies have shown that TauBr is effective in the local treatment of skin and mucosa chronic infections. Nevertheless, it is still not clear whether it can kill bacteria hidden in a biofilm or destroy biofilm and enhance the effect of antibiotics. In this study we have investigated the capacity of TauBr to inhibit in vitro the formation of P. aeruginosa biofilm. Preformed biofilm was treated with TauBr alone or TauBr and ciprofloxacin, the antibiotic commonly used in skin infections. Efficacy of TauBr was compared with that of chlorhexidine (CHX), the most effective anti-biofilm agent that has been developed to date. Our results show that TauBr and CHX are able to inhibit the formation of P. aeruginosa biofilm in vitro but only CHX destroys the mature biofilm and effectively kills hidden bacteria. In contrast, only TauBr shows antioxidant properties. It therefore suggests that CHX and TauBr could be combined in treatment of chronic infections associated with biofilm formation and generation of oxidative stress.