Yotsuji A, Mitsuyama J, Hori R, Yasuda T, Saikawa I, Inoue M, Mitsuhashi S
Research Laboratory, Toyama Chemical Co., Ltd., Japan.
Antimicrob Agents Chemother. 1988 Dec;32(12):1848-53. doi: 10.1128/AAC.32.12.1848.
The susceptibilities of 52 clinical isolates of Bacteroides fragilis to five monoanionic cephalosporins were examined. Cefoperazone showed the highest antibacterial activity, followed by ceftezole, cefazolin, cefamandole, and cephalothin. There were two groups of resistant strains: one group (ca. 15%), of which B. fragilis G-232 was a typical sample, was resistant to ceftezole (MIC, 100 micrograms/ml), cefazolin (MIC, 100 micrograms/ml), and cephalothin (MIC, 200 micrograms/ml) but not cefoperazone (MIC, 6.25 micrograms/ml) or cefamandole (MIC, 25 micrograms/ml). On the basis of studies of stability to beta-lactamase, outer membrane permeation, and affinity for penicillin-binding proteins (PBPs), we conclude that decreased affinity for PBP 3 may play an important role in the resistance to ceftezole, cefazolin, and cephalothin in B. fragilis G-232. Another group (also ca. 15%), of which B. fragilis G-242 was a representative, was resistant to all five cephalosporins (MIC, 100 to 400 micrograms/ml) and produced a high amount of beta-lactamase. Similar broad-spectrum resistance was seen in a mutant of strain G-232 that had a greater-than-30-fold increase in beta-lactamase production.
检测了52株脆弱拟杆菌临床分离株对5种单阴离子头孢菌素的敏感性。头孢哌酮显示出最高的抗菌活性，其次是头孢替唑、头孢唑林、头孢孟多和头孢噻吩。有两组耐药菌株：一组（约15%），其中脆弱拟杆菌G - 232是典型样本，对头孢替唑（MIC，100微克/毫升）、头孢唑林（MIC，100微克/毫升）和头孢噻吩（MIC，200微克/毫升）耐药，但对头孢哌酮（MIC，6.25微克/毫升）或头孢孟多（MIC，25微克/毫升）不耐药。基于对β - 内酰胺酶稳定性、外膜通透性和对青霉素结合蛋白（PBPs）亲和力的研究，我们得出结论，对PBP 3亲和力降低可能在脆弱拟杆菌G - 232对头孢替唑、头孢唑林和头孢噻吩的耐药中起重要作用。另一组（也约15%），其中脆弱拟杆菌G - 242是代表，对所有5种头孢菌素耐药（MIC，100至400微克/毫升）并产生大量β - 内酰胺酶。在β - 内酰胺酶产生增加超过30倍的G - 232菌株突变体中也观察到类似的广谱耐药性。
