Combined Effect Of Clarithromycin And Gatifloxacin On Pseudomonas Aeruginosa Biofilms In Vitro

Objective: To investigate the combined effect of clarithromycin and gatifloxacin on Pseudomonas aeruginosa biofilms in vitro. Methods: Pseudomonas aeruginosa biofilms models in vitro was established with the modified flat culture methods and was influenced by clarithromycin of different concentration. The morphological change of the samples was detected with scanning electron microscope.The minimal biofilm eradicate concentration of gatifloxacin for Pseudomonas aeruginosa biofilm was measured. Results: After influenced by clarithromycin of different concentration, the morphological change of biofilm show significant decrease of fibre-like substance and connection with each other. Compared with the 0MIC clarithromycin group, the minimal biofilm eradicate concentration of gatifloxacin significantly decreased in 1/16MIC and 1/4MIC clarithromycin group (p <0.05). Conclusion: Clarithromycin show no bactericidal activities to Pseudomonas aeruginosa in biofilm. However, both 1/4 MIC and 1/16MIC clarithromycin can enhance the bactericidal activities of gatifloxacin to Pseudomonas aeruginosa by decreasing fibre-like substance in biofilms and destroying the structure of biofilms.