Ayers L W, Jones R N, Barry A L, Thornsberry C, Fuchs P C, Gavan T L, Gerlach E H, Sommers H M
Antimicrob Agents Chemother. 1982 Nov;22(5):859-77. doi: 10.1128/AAC.22.5.859.
Cefotetan is a new, potent, 7 alpha-methoxy cephalosporin (cephamycin). The in vitro activity of cefotetan tested in a multiphasic, collaborative study against 12,260 consecutive clinical isolates and 448 selected isolates showed 93% of Enterobacteriaceae, 90% of methicillin-susceptible Staphylococcus aureus (broth dilution), 83% of Bacteroides fragilis, and 72% of non-enterococcal streptococci to be inhibited by less than or equal to 8 micrograms/ml. Beta-Lactamase-producing and -nonproducing Haemophilus influenzae strains were inhibited by less than or equal to 1.0 micrograms/ml. Cefotetan's inhibitory spectrum paralleled those of the newest generation of cephems and exceeded those of cefoxitin and cefamandole. No useful activity was present against Streptococcus faecalis or Pseudomonas aeruginosa. Cefotetan was bactericidal without significant inoculum effect and was highly resistant to hydrolysis by Richmond-Sykes types I, III, and IV beta-lactamases. Hydrolysis of the chromogenic cephalosporin PADAC (pyridine-2-azo-p-dimethylaniline cephalosporin) by type I beta-lactamases was markedly inhibited by concentrations of cefotetan similar to those of the potent inhibitor dicloxacillin. Analysis of agar disk diffusion for several disk potencies and broth dilution susceptibility tests by regression and error rate-bounding methods produced preliminary tentative zone standards (30-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 8 micrograms/ml susceptible and greater than 32 micrograms/ml resistant, or 75-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 16 micrograms/ml susceptible and greater than or equal to 64 micrograms/ml resistant) of greater than or equal to 18 mm susceptible, less than or equal to 14 mm resistant, and 15 to 17 mm indeterminate. Staphylococcus aureus testing with the 30-micrograms disk is not recommended.
头孢替坦是一种新型强效的7α-甲氧基头孢菌素（头霉烯）。在一项多阶段合作研究中，对12260株连续临床分离株和448株选定分离株进行测试，头孢替坦的体外活性显示，93%的肠杆菌科细菌、90%的甲氧西林敏感金黄色葡萄球菌（肉汤稀释法）、83%的脆弱拟杆菌和72%的非肠球菌性链球菌在小于或等于8微克/毫升的浓度下受到抑制。产β-内酰胺酶和不产β-内酰胺酶的流感嗜血杆菌菌株在小于或等于1.0微克/毫升的浓度下受到抑制。头孢替坦的抑菌谱与最新一代头孢菌素相似，且超过了头孢西丁和头孢孟多。对粪肠球菌或铜绿假单胞菌无有效活性。头孢替坦具有杀菌作用，且无明显接种量效应，对里士满-赛克斯I、III和IV型β-内酰胺酶具有高度抗性。I型β-内酰胺酶对生色头孢菌素PADAC（吡啶-2-偶氮-p-二甲基苯胺头孢菌素）的水解作用，在与强效抑制剂双氯西林浓度相似的头孢替坦浓度下受到明显抑制。通过回归和误差率边界法对几种纸片效力的琼脂纸片扩散分析和肉汤稀释药敏试验得出了初步暂定的抑菌圈标准（30微克纸片，敏感的最低抑菌浓度断点小于或等于8微克/毫升，耐药的大于32微克/毫升；或75微克纸片，敏感的最低抑菌浓度断点小于或等于16微克/毫升，耐药的大于或等于64微克/毫升），抑菌圈大于或等于18毫米为敏感，小于或等于14毫米为耐药，15至17毫米为不确定。不建议使用30微克纸片对金黄色葡萄球菌进行检测。
