Effects of macrolides on Pseudomonas aeruginosabiofilms

Purpose:To investigate the effects of macrolides on Pseudomonasmol aeruginosa biofilms. Methods: Pseudomonas aeruginosa biofilm was prepared using high malecular membrane, the number of colonies in biofilm were counted, then observed by scanning electron microscopy. Results: The number of colonies in biofilms were reduced from 10×10 9 cfu/cm 2 in controlled biofilmm to 1.9×10 3 cfu/cm 2 treated with 2?mg/L azithromycin, and to 5.0×10 3 cfu/cm 2 treated with 2?mg/L erythromycin. The number of colonies in biofilms treated with azithromycin, erythromycin or medemycin alone had no significant effect on biofilm, however when treated with azithromycin or erythromycin in combination with ciprofloxacin, the number of colonies decreased to 0.9%-2.2% of the original. No significant change was observed when medemycin combined with ciprofloxacin. Similar results were obtained when observed with scanning electron microcopy conclusions. Conclusions:These results indicate that azithromycin and erythromycin can inhibit the formation of biofilm by P. aeruginosa ; enhance the bactericidal action of ciprofloxacin on bacteria within the biofilm. Midecamycin has no such effect.