Giovanetti E, Montanari M P, Marchetti F, Varaldo P E
Institute of Microbiology, University of Ancona, Via Ranieri, Monte d'Ago, 60131 Ancona, Italy.
J Antimicrob Chemother. 2000 Dec;46(6):905-8. doi: 10.1093/jac/46.6.905.
Two ketolides, telithromycin and HMR 3004, were evaluated for their in vitro activity against erythromycin-susceptible and -resistant strains of Streptococcus pyogenes and Streptococcus pneumoniae. On the basis of their resistance to macrolide, lincosamide and streptogramin (MLS) antibiotics, erythromycin-resistant test strains were assigned to the constitutive resistance (cMLS) phenotype, the inducible resistance (iMLS) phenotype or the M phenotype. iMLS S. pyogenes strains were further subdivided into the three recently described subtypes iMLS-A, -B and -C. Telithromycin and HMR 3004 were uniformly and highly active against pneumococci (regardless of their susceptibility or resistance to erythromycin and/or penicillin), erythromycin-susceptible S. pyogenes and erythromycin-resistant S. pyogenes strains of the M phenotype (in which resistance is mediated by an efflux system) or iMLS-B or -C phenotype (in which resistance is mediated by a methylase encoded by the ermTR gene). Both ketolides were less active against erythromycin-resistant S. pyogenes strains with the cMLS phenotype or the iMLS-A subtype (where resistance is mediated by a methylase encoded by the ermAM gene), these strains ranging in phenotype from the upper limits of susceptibility to low-level resistant.
对两种酮内酯类药物，即泰利霉素和HMR 3004，评估了它们对红霉素敏感和耐药的化脓性链球菌及肺炎链球菌菌株的体外活性。根据对大环内酯类、林可酰胺类和链阳菌素（MLS）抗生素的耐药情况，将耐红霉素的测试菌株分为组成型耐药（cMLS）表型、诱导型耐药（iMLS）表型或M表型。化脓性链球菌iMLS菌株进一步细分为最近描述的三种亚型iMLS-A、-B和-C。泰利霉素和HMR 3004对肺炎球菌（无论其对红霉素和/或青霉素敏感或耐药）、红霉素敏感的化脓性链球菌以及M表型（耐药由外排系统介导）或iMLS-B或-C表型（耐药由ermTR基因编码的甲基化酶介导）的耐红霉素化脓性链球菌菌株均具有一致且高度的活性。两种酮内酯类药物对具有cMLS表型或iMLS-A亚型（耐药由ermAM基因编码的甲基化酶介导）的耐红霉素化脓性链球菌菌株活性较低，这些菌株的表型范围从敏感性上限到低水平耐药。
