Effect of subinhibitory concentrations of macrolides on expression of flagellin in Pseudomonas aeruginosa and Proteus mirabilis

In the present study we showed by molecular analysis that the inhibition of motility by macrolides in Proteus mirabilis and Pseudomonas aeruginosa was well correlated with the loss of the expression of flagellin. Erythromycin , clarithromycin, and azithromycin at subinhibitory concentrations (sub-MIC s) suppressed the expression of flagellin dose dependently. Azithromycin ha d the strongest inhibitory effect on the expression of P. aeruginosa flagel lin, whereas 16-membered rokitamycin had only a weak inhibitory effect. The se results indicate the potential effectiveness of sub-MICs of erythromycin , clarithromycin, and azithromycin for the treatment of patients with P. mi rabilis and P. aeruginosa infections.