Objective: To observe the effects on Pseudomonas aeruginosa biofilm of non-antipseudomonal drugs such as erythromycin and fosfomycin.
Methods: Clinical isolates of Pseudomonas aeruginosa in respiratory infection and ATCC27853 were cultivated in TSB-Teflon and NS-Teflon system respectively for biolfilm formation. Biofilm was observed under scanning electronic microscope (SEM). MICs were determined by broth micro-dilution.
Results: SEM showed that biofilm of clinical isolate in TSB-Teflon system and ATCC27853 in NS-Teflon system increased as being cultivated for longer in 1, 3 and 7 days. And biofilm formation in the process of cultivating was inhibited by SubMIC of erythromycin and fosfomycin. MICs evaluation suggested that there were synergetic effects against biofilm Pseudomonas aeruginosa when SubMIC of erythromycin and fosfomycin were combined with ceftazidime or levofloxacin in vitro.
Conclusion: SubMIC of erythromycin and fosfomycin could inhibit Pseudomonas aeruginosa biofilm in vitro.