Yourassowsky E, Van der Linden M P, Crokaert F
Department of Microbiology, Brugmann University Hospital, Brussels, Belgium.
J Antimicrob Chemother. 1990 Aug;26(2):185-92. doi: 10.1093/jac/26.2.185.
Phase-contrast microscopy, killing-curves and turbidimetric growth-curves were used in a comparative study of the antibacterial effects of a new carbapenem, meropenem (SM 7338) and imipenem on five strains of Proteus mirabilis. Despite the low MIC (0.2 mg/l) of imipenem for the five strains included in our study, the MBC remained relatively high (4.4 mg/l). During the first few hours of incubation, imipenem induced large lemon-shaped cells while the turbidity increased without substantial changes in culture viability. Later, most of the cell-wall deficient bacteria generated small spheroplasts until the antibiotic concentration exceeded 32 times the MIC. The MIC of meropenem was lower (0.03 mg/l) with an MBC (0.08 mg/l) very close to the MIC. Meropenem also induced large bodies but these cell-wall deficient bacteria did not generate small round bodies as observed with imipenem. In conclusion, imipenem produced in strains of Pr. mirabilis an amdinocillin-like change in cell morphology, responsible for the discrepancies observed between MIC and MBC. This effect was not observed with meropenem.
采用相差显微镜、杀菌曲线和比浊生长曲线，对新型碳青霉烯类药物美罗培南（SM 7338）和亚胺培南对5株奇异变形杆菌的抗菌作用进行了比较研究。尽管亚胺培南对我们研究中纳入的5株菌株的最低抑菌浓度（MIC）较低（0.2mg/l），但其最低杀菌浓度（MBC）仍然相对较高（4.4mg/l）。在培养的最初几个小时内，亚胺培南诱导产生大的柠檬形细胞，同时浊度增加，但培养物活力没有实质性变化。后来，大多数细胞壁缺陷细菌产生小的原生质球，直到抗生素浓度超过MIC的32倍。美罗培南的MIC较低（0.03mg/l），MBC（0.08mg/l）非常接近MIC。美罗培南也诱导产生大的菌体，但这些细胞壁缺陷细菌没有像亚胺培南那样产生小的圆形菌体。总之，亚胺培南在奇异变形杆菌菌株中产生了类似氨曲南的细胞形态变化，这导致了MIC和MBC之间观察到的差异。美罗培南未观察到这种效应。
