左氧氟沙星对幽门螺杆菌体外抗菌活性的评价

目的 体外试验检测左氧氟沙星对幽门螺杆菌(Helicobacter.pylori)的敏感性，并以克拉霉索和阿莫西林进行对照研究。方法 琼脂稀释法检测左氧氟沙星对52株幽门螺杆菌的最低抑菌浓度，同时比较在MH培养基pH为4．0、5．0、7．0条件下的MIC。结果 左氧氟沙星耐药菌株1．9％，阿莫西林耐药菌株11．5％，克拉霉索耐药菌株25％。同时对阿莫西林和克拉霉索耐药的菌株(9．6％)，对左氧氟沙星均敏感。左氧氟沙星耐药率明显低于克拉霉素(P＜0．01)，阿莫西林的耐药率也低于克拉霉素(P＜0．05)，但与左氧氟沙星的耐药率无明显差异(P＞0．05)。左氧氟沙星在酸性环境下抗菌活性降低。结论 本地区幽门螺杆菌耐药菌株多见，左氧氟沙星是一种可供选择的治疗药物。

In vitro activities of levofloxacin against Helicobacter pylori

Objective To evaluate antibacterial activity of levofloxacin to Helicobacter pylori ( H.pylori ) strains. Methods The minimum inhibitory concentration (MIC) for 52 clinical isolates was detected by agar dilution method and compared with those of amoxicillin and clarithromycin. To investigate the effects of pH variation on the susceptibility of H.pylori to levofloxacin, Mueller Hinton agar with 7% defibrinated sheep blood was adjusted to a pH range of 4 0 to 7 0 by adding hydrochloric acid. Results 1 9% of strains was resistant to levofloxacin, 25% was resistant to clarithromycin and 11 5% was resistant to amoxicillin. Dual resistance to amoxicillin and clarithromycin was demonstrated in five H.pylori strains, which were susceptible to levofloxacin. The prevalence of strains with resistance to clarithromycin was higher than that of strains with resistance to levofloxacin and amoxicillin ( P <0 05). The activity of levofloxacin was diminished under acidic environment ( P <0 01). Conclusions The study indicated a high rate of resistance of H.pylori to amoxicillin and clarithromycin in this area. Levofloxacin is an attractive candidate for the treatment of Helicobacter pylori infection in case of combined resistance of the bacterium to the first line antimicrobial agents.