Inhibitory effect of roxithromycin on biofilm formation of Pseudomonas aeruginosa.

Biofilm formed by bacteria has recently has been shown to be involved in making infectious diseases intractable. We indirectly measured and evaluated the inhibitory effect of roxithromycin (RXM) on biofilm formation on the inside of a plastic test tube by determining the number of living bacteria in the biofilm. As a result, RXM was found to inhibit biofilm formation even though it does not have antimicrobial activity against Pseudomonas aeruginosa. In addition, this inhibitory effect on biofilm formation was observed at in vivo concentrations which are possible in clinical use of RXM. Thus, there is a possibility that RXM is effective against infectious otolaryngological diseases when biofilm formation is likely to be pathologically involved, even if the detected bacteria are not sensitive to the drug.