Effects of combined treatment with sansanmycin and macrolides on Pseudomonas aeruginosa and formation of biofilm.
OBJECTIVE
To observe the effects of combined treatment with sansanmycin and macrolides on Pseudomonas aeruginosa and formation of biofilm.


METHODS
Micro-dilution method was used to determine the minimal inhibitory concentrations (MICs) of sansanmycin, gentamycin, carbenicillin, polymyxin B, roxithromycin, piperacillin, and tazobactam. PA1 and PA27853 biofilms were observed under optical microscope after staining and under SEM after treatment with sansanmycin at different dosages and combined treatment with sansanmycin and roxithromycin. Viable bacteria in PA1 and PA27853 biofilms were counted after treatment with sansanmycin at different dosages or combined treatment with sansanmycin and roxithromycin.


RESULTS
The MIC of sansanmycin was lower than that of gentamycin and polymyxin B, but was higher than that of carbenicillin. Roxithromycin enhanced the penetration of sansanmycin to PA1 and PA27853 strains through biofilms. PA1 and PA27853 biofilms were gradually cleared with the increased dosages of sansanmycin or with the combined sansanmycin and roxithromycin.


CONCLUSIONS
Sub-MIC levels of roxithromycin and sansanmycin substantially inhibit the generation of biofilms and proliferation of bacteria. Therefore, combined antibiotics can be used in treatment of intractable bacterial infection.
Li
Yue
Y
Department of Microbiology, Tianjin Medical University, Tianjin 300070, China.
Xie
Yun-Ying
YY
Chen
Ru-Xian
RX
Xu
Hong-Zhang
HZ
Zhang
Guo-Ji
GJ
Li
Jin-Zhe
JZ
Li
Xiao-Mian
XM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000254:growth & development*; D002522:Chlorocebus aethiops; D004359:Drug Therapy, Combination; D018942:Macrolides / Q000008:administration & dosage / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D014529:Uridine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D014709:Vero Cells
D000900:Anti-Bacterial Agents; D018942:Macrolides; D009842:Oligopeptides; C519865:sansanmycin; D014529:Uridine