Aldridge K E, Schiro D D
Department of Medicine, LSU Medical Center, New Orleans 70112.
Diagn Microbiol Infect Dis. 1994 Nov;20(3):135-42. doi: 10.1016/0732-8893(94)90107-4.
Two standardized susceptibility test methods, a broth microdilution (BMD) and agar dilution (AD) method were performed on a total of 441 clinical isolates of anaerobes with ceftizoxime, cefotaxime, ceftriaxone, cefoxitin, piperacillin, and metronidazole. Against the 339 strains of the Bacteroides fragilis group BMD minimum inhibitory concentration (MIC) values were lower than those from AD testing for all the beta-lactams. Overall for the B. fragilis group and the beta-lactams, the mode MIC values were two- to 64-fold lower, and the MIC50 values two- to eightfold lower. Resistance rates were 11%-28% higher overall with AD results and were higher especially for non-B. fragilis species. For non-Bacteroides anaerobes no major discrepancies were noted for Prevotella species, Peptostreptococcus species, and Viellonella parvula. With Clostridium species and Eubacterium species, some differences were noted with ceftizoxime because of differences in cut-off points. These data illustrate the magnitude of differences in results produced by the two methods using essentially the same test medium for the B. fragilis group. Fortunately, such major discordant results were not widely noted with other groups of anaerobes.
采用肉汤微量稀释法（BMD）和琼脂稀释法（AD）这两种标准化药敏试验方法，对441株临床分离厌氧菌进行了头孢唑肟、头孢噻肟、头孢曲松、头孢西丁、哌拉西林和甲硝唑的药敏试验。对于339株脆弱拟杆菌属菌株，所有β-内酰胺类药物的BMD最低抑菌浓度（MIC）值均低于AD试验结果。总体而言，对于脆弱拟杆菌属和β-内酰胺类药物，MIC值的众数低2至64倍，MIC50值低2至8倍。AD试验结果的总体耐药率高11%-28%，尤其是非脆弱拟杆菌属菌种。对于非拟杆菌属厌氧菌，普雷沃菌属、消化链球菌属和小韦荣球菌未发现重大差异。对于梭菌属和真杆菌属，由于临界值的差异，头孢唑肟存在一些差异。这些数据说明了两种方法在使用基本相同的试验培养基检测脆弱拟杆菌属时结果差异的程度。幸运的是，其他厌氧菌组未广泛发现如此重大的不一致结果。
