title: Effects of combined treatment with sansanmycin and macrolides on Pseudomonas aeruginosa and formation of biofilm.
abstract: 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.
authors.affiliation: Department of Microbiology, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Yun-Ying
authors.initials: YY
authors.lastname: Xie
authors.forename: Ru-Xian
authors.initials: RX
authors.lastname: Chen
authors.forename: Hong-Zhang
authors.initials: HZ
authors.lastname: Xu
authors.forename: Guo-Ji
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Jin-Zhe
authors.initials: JZ
authors.lastname: Li
authors.forename: Xiao-Mian
authors.initials: XM
authors.lastname: Li
mesh_terms: 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
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D009842:Oligopeptides; C519865:sansanmycin; D014529:Uridine