国产氟罗沙星体外抗菌活性研究

In vitro activity of fleroxacin, compared with those of other antimicrobial agents

测定国产氟罗沙星对４９３株临床分离细菌的最低抑菌浓度（ＭＩＣ），并与氧氟沙星、洛美沙星、环丙沙星和几种头孢菌素、氨基糖苷类抗生素作了比较。结果表明：氟罗沙星对革兰氏阴性细菌有强大抗菌活性，对肠杆菌科细菌的ＭＩＣ９０≤１μｇ／ｍｌ。对铜绿假单胞菌亦有较强抗菌活性，其ＭＩＣ５０、ＭＩＣ９０分别为２和４μｇ／ｍｌ。金葡球菌（含ＭＲＳＡ菌株）对氟罗沙星亦很敏感，ＭＩＣ９０≤１μｇ／ｍｌ。链球菌属对其基本耐药，ＭＩＣ９０为８～１６μｇ／ｍｌ。对大多数常见致病菌，氟罗沙星体外抗菌活性与氧氟沙星、洛美沙星相近，稍逊于环丙沙星。对革兰氏阴性菌，氟罗沙星与头孢噻肟、头孢他啶、阿米卡星相当，优于头孢唑林、氨苄西林、哌拉西林、庆大霉素。耐庆大霉素、头孢菌素菌株对氟罗沙星仍敏感。细菌对氟罗沙星单步自发耐药突变频率极低，但通过连续传代培养可以培育出对氟罗沙星高度耐药菌株。

The in vitro activity of fleroxacin was compared with those of lomefloxacin, ofloxacin, ciprofloxacin, several cephalosprins and aminoglycosides. Fleroxa cin inhibited the majority of Enterobacteriaceae isolates at a concentration of ≤1μg/ml. The MIC 90 for Pseudomonus aeruginosa was 4μg/ml; Staphylococcus aureus isolates, including methcillin resistant strains, were inhibited by≤1μg/ml; Streptococcal sp. were inhibited by 16μg/ml. The overall activity of fleroxacin was similar to those of lomefloxacin, ofloxacin, but less active than that of ciprofloxacin. To Gram negative bacterial strains, fleroxacin was similar in antibacterial activity to cefotaxime, ceftazidime and amikacin, superior to cefazo lin, piperacillin and gentamicin. Fleroxacin is also active against bacterial strains resistant to gentamicin and broad spectrum cephalosporins. Although the mutant frequency of spontane ous resistance to fleroxacin was low, but resistant bacteria could be selected by repeated subcultures.