Barry A L, Pfaller M A, Fuchs P C
Clinical Microbiology Institute, Tualatin, Oregon 97062.
J Antimicrob Chemother. 1993 Mar;31 Suppl C:27-37. doi: 10.1093/jac/31.suppl_c.27.
Dirithromycin and its bioactive metabolite (erythromycylamine) were compared in vitro to erythromycin against 450 bacterial isolates. Dirithromycin and erythromycylamine did not differ in their in-vitro activity and the two compounds were additive when combined in equal proportions. Both compounds were active against erythromycin-susceptible bacteria but erythromycin was two to four times more potent on a weight-to-weight basis. Interpretive criteria for dirithromycin were not based on achievable blood concentrations since tissue concentrations may be 20-30 times greater than peak serum levels. Dirithromycin-susceptible strains were those with zones > or = 19 mm in diameter (15 micrograms dirithromycin disc) or MIC < or = 2.0 mg/L and resistance was defined as a zone < or = 15 mm or MIC > or = 8.0 mg/L. Interpretive criteria for testing Haemophilus influenzae on Haemophilus Test Medium (HTM) agar were not defined because of the drug's poor activity in the test system used. Two multi-laboratory studies were also undertaken, one to define quality control limits for disc diffusion tests and the other to define broth microdilution MIC control limits for tests with dirithromycin.
将地红霉素及其生物活性代谢物（红霉素胺）在体外与红霉素针对450株细菌分离物进行了比较。地红霉素和红霉素胺的体外活性无差异，且当以等比例组合时这两种化合物具有相加作用。两种化合物对红霉素敏感菌均有活性，但按重量计红霉素的效力要高两到四倍。地红霉素的解释标准并非基于可达到的血药浓度，因为组织浓度可能比血清峰值水平高20至30倍。对地红霉素敏感的菌株是指直径大于或等于19毫米（15微克地红霉素纸片）或最低抑菌浓度（MIC）小于或等于2.0毫克/升的菌株，耐药性定义为抑菌圈小于或等于15毫米或MIC大于或等于8.0毫克/升。由于该药物在所使用的测试系统中活性较差，因此未定义在嗜血杆菌测试培养基（HTM）琼脂上检测流感嗜血杆菌的解释标准。还开展了两项多实验室研究，一项用于确定纸片扩散试验的质量控制限度，另一项用于确定用地红霉素进行试验的肉汤微量稀释MIC控制限度。
