Köhler T, Michea-Hamzehpour M, Epp S F, Pechere J C
Department of Genetics and Microbiology, Centre Médical Universitaire, Geneva 4, Switzerland.
Antimicrob Agents Chemother. 1999 Feb;43(2):424-7. doi: 10.1128/AAC.43.2.424.
While meropenem MICs were strongly influenced by the presence or absence of the MexAB-OprM efflux pump in both OprD-proficient and -deficient strain backgrounds, MICs of imipenem and of ER-35786 remained unchanged, demonstrating that meropenem is a substrate of MexAB-OprM but not imipenem and ER-35786. In vitro, all three carbapenems selected loss of OprD as a first mechanism of resistance. However, in an OprD-deficient background, meropenem was able to select MexAB-OprM overproducers as a secondary resistance mechanism, while ER-35786 selected a mutant cross-resistant to sparfloxacin and cefpirome.
在产OprD和不产OprD的菌株背景中，美罗培南的最低抑菌浓度（MIC）受MexAB-OprM外排泵的存在与否的强烈影响，但亚胺培南和ER-35786的MIC保持不变，这表明美罗培南是MexAB-OprM的底物，而亚胺培南和ER-35786不是。在体外，所有三种碳青霉烯类药物都选择了OprD缺失作为第一种耐药机制。然而，在OprD缺陷背景下，美罗培南能够选择MexAB-OprM过表达菌作为第二种耐药机制，而ER-35786选择了对司帕沙星和头孢匹罗交叉耐药的突变体。
