罗红霉素与氟罗沙星联合应用对铜绿假单胞菌生物被膜的影响

Influence of roxithromycin combined with fleroxacin on bacterial biofilm induced by pseudomonas aeruginosa

目的研究罗红霉素（RXM）对铜绿假单胞菌生物被膜（BF）形成的抑制及其对氟罗沙星（FLRX）杀灭BF细菌的增效作用。方法采用改良的平板培养法建立BF模型，经不同浓度RXM和FLRX合用后，进行银染法鉴定、扫描电镜（SEM）观察、多糖蛋白复合物（GLX）含量测定、噻唑兰试剂盒（MTF）法测定BF存活细菌数。结果1／16倍最低抑菌浓度（MIC）、1／4MICRXM可非常显著地抑制BF多糖蛋白复合物的合成（P＜0.05），抑制率分别为25.3％和42.9％。与未用RXM组比较，1／16MC和1/4RXM可显著减少1/4MIC和1／2MICFLRX组BF存活细菌数（P＜0.05）。结论大环内酯类药物RXM通过抑制铜绿假单胞菌GLX合成，从而增强FLRX对BF的渗透，对FLRX杀灭BF中铜绿假单胞菌有增效作用。

Objective To investigate the influence of roxithromycin (RXM) on the productin of glycocalyx (GLX) and the synergic effect of RXM and fleroxacin (FLRX) on P. Aeruginosa biofilms Methods Bacterial biofilm (BF) was established and was influenced by RXM and FLRX with diferent concentrations. The samples were detected with scanning electron microscope and by a rapid method ther BF was stained with AgNO3 solution. The synergism of antibacterial activities of RXM and FLRX to P. Aeruginosa was studied by computer image analysis and MTT method. Results GLX production was reduced significantly by both 1/16 MIC and 1/4 MIC RXM (P＜0.01). 1/16 MIC and 1/4 MIC RXM showed no bactericidal activities to P. Aeruginosa in biofilms, while viable counts in biofilms almost had no difference. However, RXM could enhance the bactericidal activity of FLRX to P. Aeruginosa in biofilms. When FLRX of different concentrations was combined with 1/16 MIC and 1/4 MIC RXM respectively , the difference of the stained BF was counted up by computer image analysis system with significance of P＜0.05 and the viable counts were reduced significantly (P＜0.05). The results was in accordance with SEM pictures . Conclusion RXM has no direct bactericidal activities to P. Aeruginosa in biofilms, but it could inhibit GLX production . It can be considerded that RXM could enhance antibacterial activities of FLRX by enhancing the permeability of FLREX into biofilms.