Easmon C S, Crane J P
J Antimicrob Chemother. 1984 Jun;13(6):585-91. doi: 10.1093/jac/13.6.585.
Rifapentine, a new cyclopentyl rifamycin, was weight for weight less active than rifampicin against Staphylococcus aureus. It was, however, equally effective at reducing the survival of Staph. aureus within human neutrophils even at concentrations below the conventionally determined MIC. The intracellular survival of antibiotic-resistant Staph. aureus was affected by neither agent. The bactericidal activity of neutrophil sonicates after exposure to both antibiotics showed that rifapentine was concentrated three-fold more than rifampicin. Uptake was temperature dependent and rapidly reached a plateau within 10 min. Uptake of rifampicin was unaffected by pH whereas that of rifapentine was reduced when the pH was lowered from 7.3 to 5. Studies with the metabolic inhibitors, sodium cyanide and potassium fluoride, suggested a minor role for both oxidative and glycolytic metabolism in this process. However, neither inhibitor had any demonstrable effect on the intracellular killing of Staph. aureus by either rifapentine or rifampicin.
利福喷汀是一种新型环戊基利福霉素，按重量计算，其对金黄色葡萄球菌的活性低于利福平。然而，即使在低于常规测定的最低抑菌浓度（MIC）的浓度下，它在降低人中性粒细胞内金黄色葡萄球菌的存活率方面同样有效。耐抗生素金黄色葡萄球菌的细胞内存活率不受这两种药物的影响。暴露于两种抗生素后，中性粒细胞超声裂解物的杀菌活性表明，利福喷汀的浓缩倍数比利福平高三倍。摄取是温度依赖性的，在10分钟内迅速达到平稳状态。利福平的摄取不受pH值影响，而当pH值从7.3降至5时，利福喷汀的摄取减少。用代谢抑制剂氰化钠和氟化钾进行的研究表明，氧化代谢和糖酵解代谢在这一过程中作用较小。然而，两种抑制剂对利福喷汀或利福平在细胞内杀灭金黄色葡萄球菌均无明显作用。
