Barry A L, Fuchs P C, Brown S D
Clinical Microbiology Institute, Tualatin, OR 97062, USA.
J Antimicrob Chemother. 1997 May;39 Suppl A:87-92. doi: 10.1093/jac/39.suppl_1.87.
For testing bacterial susceptibility to the streptogramin quinupristin/dalfopristin, it seems reasonable that the test reagent should contain a similar ratio of the two compounds as in the therapeutic material, i.e. 30% quinupristin and 70% dalfopristin. The precise ratio of quinupristin to dalfopristin is not critical as long as threshold concentrations of both drugs are present. In-vitro tests were not altered by minor changes in pH, incubation in CO2 or by addition of lysed horse blood to the medium. Filter paper discs containing 15 micrograms of the quinupristin/dalfopristin reagent are preferred for agar diffusion susceptibility testing in order to optimize disc tests with enterococci. Provisional interpretive criteria for pathogens not requiring blood or increased CO2 are: susceptible, inhibition zone diameters of > or = 19 mm or MIC < or = 1.0 mg/L; intermediate, 16-18 mm or MIC 2.0 mg/L; resistant, < or = 15 mm or MIC > or = 4.0 mg/L. Those criteria will need to be reassessed as clinical experiences become available. Of particular concern is the role of quinupristin/dalfopristin in the treatment of infections due to Haemophilus influenzae or Enterococcus faecalis: the clinically relevant interpretive category for each of those two species is yet to be determined.
为检测细菌对链阳菌素奎奴普丁/达福普汀的敏感性，测试试剂中两种化合物的比例应与治疗用药物中的比例相似，即30%奎奴普丁和70%达福普汀，这似乎是合理的。只要两种药物都存在阈值浓度，奎奴普丁与达福普汀的精确比例并不关键。体外试验不受pH值的微小变化、在二氧化碳环境中孵育或向培养基中添加裂解马血的影响。为优化对肠球菌的纸片扩散药敏试验，含15微克奎奴普丁/达福普汀试剂的滤纸圆片更适合用于琼脂扩散药敏试验。对于不需要血液或增加二氧化碳的病原体，暂定的解释标准为：敏感，抑菌圈直径≥19毫米或最低抑菌浓度（MIC）≤1.0毫克/升；中介，16 - 18毫米或MIC为2.0毫克/升；耐药，≤15毫米或MIC≥4.0毫克/升。随着临床经验的积累，这些标准需要重新评估。特别值得关注的是奎奴普丁/达福普汀在治疗流感嗜血杆菌或粪肠球菌感染中的作用：这两种菌种各自的临床相关解释类别尚未确定。
