Stratton C W, Weeks L S, Aldridge K E
Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee.
Diagn Microbiol Infect Dis. 1991 Sep-Oct;14(5):377-82. doi: 10.1016/0732-8893(91)90064-m.
Time-kill kinetic methodology was used to evaluate the bactericidal activity of cefoxitin, cefotetan, clindamycin, and metronidizole against cefoxitin-susceptible and cefoxitin-resistant isolates of the Bacteroides fragilis group. Overall, metronidazole was the most bactericidal agent, with all isolates being killed with less than or equal to 4 micrograms/ml at 24 hr. Clindamycin was the next most bactericidal agent, with 20 of 26 isolates being killed with less than 16 micrograms/ml. Six isolates with clindamycin MICs greater than or equal to 64 micrograms/ml were not killed at 24 hr, with concentrations as high as 256 micrograms/ml. Cefoxitin and cefotetan were the least bactericidal agents tested. Seven isolates with MICs of greater than or equal to 64 micrograms/ml to each agent demonstrated a lack of killing at 24 hr, with concentrations of the respective agent as high as 256 micrograms/ml. At concentrations with either agent of 32 micrograms/ml, the remaining 19 isolates were killed at 24 hr. Of the six B. fragilis isolates resistant to clindamycin, four were also resistant to both cefoxitin and cefotetan. We conclude that in hospitals with cefoxitin-resistant B. fragilis group isolates, metronidazole would provide appropriate therapy.
采用时间-杀菌动力学方法评估头孢西丁、头孢替坦、克林霉素和甲硝唑对脆弱拟杆菌群中对头孢西丁敏感及耐药菌株的杀菌活性。总体而言，甲硝唑是最具杀菌活性的药物，所有菌株在24小时时用小于或等于4微克/毫升的浓度即可被杀灭。克林霉素是其次具杀菌活性的药物，26株菌株中有20株在浓度小于16微克/毫升时被杀灭。6株对克林霉素的最低抑菌浓度大于或等于64微克/毫升的菌株在24小时时未被杀灭，即便浓度高达256微克/毫升。头孢西丁和头孢替坦是所测试的杀菌活性最低的药物。7株对每种药物的最低抑菌浓度大于或等于64微克/毫升的菌株在24小时时未显示出被杀灭，即便各自药物的浓度高达256微克/毫升。在浓度为32微克/毫升的任何一种药物作用下，其余19株菌株在24小时时被杀灭。在6株对克林霉素耐药的脆弱拟杆菌菌株中，有4株同时对头孢西丁和头孢替坦耐药。我们得出结论，在存在对头孢西丁耐药的脆弱拟杆菌群菌株的医院中，甲硝唑可提供合适的治疗。
