六种氟喹诺酮对肠球菌的体外抗菌活性及利血平的影响

目的：研究氟喹诺酮类抗菌药物对临床分离肠球菌的体外抗菌活性,以及多重耐药泵抑制剂利血平对抗菌活性的影响.方法：收集临床分离的101株肠球菌（66株粪肠球菌和35株屎肠球菌）,用琼脂稀释法测定应用利血平前后6种氟喹诺酮对菌株的最低抑菌浓度（MIC）.结果：诺氟沙星、环丙沙星、氧氟沙星、左氧氟沙星、加替沙星、莫西沙星对66株粪肠球菌的MIC90依次为256、64、64、16、16、8 mg/L,对35株屎肠球菌的MIC90依次为＞512、512、128、128、32、32 mg/L.应用利血平之后,上述6种药物对粪肠球菌抗菌活性提高（MIC下降2倍或2倍以上）的株数依次为66（100%）、54（81.8%）、4（6.1%）、4（6.1%）、32（48.5%）和3（4.5%）株,对屎肠球菌抗菌活性提高的株数依次为35（100%）、29（82.9%）、1（2.9%）、0（0%）、6（20.7%）和2（5.7%）株.结论：新氟喹诺酮加替沙星、莫西沙星增强了对肠球菌的抗菌活性,利血平能够提高全部或部分被检测肠球菌对诺氟沙星、环丙沙星和加替沙星的敏感性,但仅使少数被检测肠球菌对氧氟沙星、左氧氟沙星和莫西沙星的敏感性提高.

Antibacterial Activities of Six Fluoroquinolones against Enterococcus in Vitro and the Effect of Reserpine on Antibacterial Activities

Objective: To study the antibacterial activities of fluoroquinolones on clinical isolated enterococcus in vitro and the effect of multidrug resistance efflux pump inhibitor reserpine on antibacterial activities. Methods: 101 strains of clinical isolated enterococcus were collected, including 66 strains of enterococcus faecalis and 35 strains of enterococcus faecium. The MICs of six fluoroquinolones in the absence or presence of reserpine were detected by agar dilution method. Results: The MIC90s of norfloxacin, ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, moxifloxacin to 66 strains of enterococcus faecalis were 256, 64, 64, 16, 16, and 8 mg/L respectively. The MIC90s of norfloxacin, ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, moxifloxacin to 35 strains of enterococcus faecium were >512, 512, 128, 128, 32, and 32 mg/L respectively. After the use of reserpine, the increased sequence of anti-enterococcus faecalis activity was 66(100%), 54(81.8%), 4(6.1%), 4(6.1%), 32(48.5%) and 3(4.5%) respectively, and it was 35(100%), 29(82.9%), 1(2.9%), 0(0%), 6(20.7%) and 2(5.7%)for enterococcus faecium respectively. Conclusion: New fluoroquinolones, such as gatifloxacin and moxifloxacin, increase the antibacterial activities against enterococcus. Reserpine can improve the antibacterial activities of norfloxacin, ciprofloxacin and gatifloxacin against all or a portion of enterococcus, while improve the antibacterial activities of ofloxacin, levofloxacin and moxifloxacin against few of enterococcus.