Powell M, Seetulsingh P, Williams J D
London Hospital Medical College, UK.
J Antimicrob Chemother. 1989 Sep;24 Suppl A:175-81. doi: 10.1093/jac/24.suppl_a.175.
The in-vitro activity of the new carbapenem, meropenem, was compared with that of imipenem, five other beta-lactams, chloramphenicol and ciprofloxacin against 223 isolates of Haemophilus influenzae. This number included 115 ampicillin-susceptible, and 56 beta-lactamase positive isolates and 52 beta-lactamase negative isolates with reduced susceptibility to ampicillin. The activities of chloramphenicol and ciprofloxacin did not vary between groups of isolates delineated by their susceptibility to ampicillin. In contrast with ampicillin and piperacillin, the two carbapenems and three cephalosporins tested showed no reduction in activity against beta-lactamase producing isolates. beta-Lactam concentrations required for inhibition of 50% and 90% of beta-lactamase negative isolates with reduced susceptibility to ampicillin (MIC greater than or equal to 1 mg/l) were increased in comparison with similar concentrations required for the ampicillin-susceptible group. The differences in meropenem and imipenem activities between these two groups were much smaller than those observed for each of the other beta-lactams. MICs of meropenem were consistently the lower of the two carbapenems for all isolates. In addition, there were no notable increases in the concentrations of meropenem required for inhibition of the isolates least susceptible to imipenem (MIC greater than or equal to 4 mg/l), suggesting that differences in penetration and/or target-binding properties exist not only between the carbapenems and other beta-lactams, but also between meropenem and imipenem.
将新型碳青霉烯类药物美罗培南的体外活性与亚胺培南、其他五种β-内酰胺类药物、氯霉素及环丙沙星针对223株流感嗜血杆菌的活性进行了比较。这223株菌包括115株对氨苄西林敏感的菌株、56株β-内酰胺酶阳性菌株以及52株对氨苄西林敏感性降低的β-内酰胺酶阴性菌株。氯霉素和环丙沙星的活性在根据对氨苄西林敏感性划分的不同菌株组之间没有差异。与氨苄西林和哌拉西林不同，所测试的两种碳青霉烯类药物和三种头孢菌素对产β-内酰胺酶的菌株没有表现出活性降低。与氨苄西林敏感组所需的类似浓度相比，抑制对氨苄西林敏感性降低的（最低抑菌浓度大于或等于1mg/L）50%和90%的β-内酰胺酶阴性菌株所需的β-内酰胺浓度有所增加。这两组之间美罗培南和亚胺培南活性的差异远小于其他每种β-内酰胺类药物所观察到的差异。对于所有菌株，美罗培南的最低抑菌浓度在两种碳青霉烯类药物中始终较低。此外，抑制对亚胺培南最不敏感的菌株（最低抑菌浓度大于或等于4mg/L）所需的美罗培南浓度没有显著增加，这表明不仅在碳青霉烯类药物与其他β-内酰胺类药物之间，而且在美罗培南和亚胺培南之间存在渗透和/或靶点结合特性的差异。
