Odenholt I, Holm S E, Cars O
Department of Infectious Diseases and Clinical Bacteriology, Uppsala University, Sweden.
J Antimicrob Chemother. 1989 Aug;24(2):147-56. doi: 10.1093/jac/24.2.147.
A postantibiotic effect (PAE) for Streptococcus pyogenes M12, P1800 was induced by 10 x MIC of benzylpenicillin for 2 h in vitro. The PAE was found to be 2.4 h (range 1.75-3.0 h). No incorporation of 3H-thymidine by the streptococci occurred during the first hours of the postantibiotic phase (PA-phase), indicating that bacterial cell division was inhibited during this period. However, these bacteria showed the same killing rate as previously unexposed control cultures when 10 x MIC of benzylpenicillin was added during the PA-phase. When bacteria in PA-phase were re-exposed to penicillin at a concentration of 0.2 x MIC multiplication of the bacteria was inhibited for 6-7 h, while at a concentration of 0.3 x MIC slow killing was induced. In contrast, previously untreated controls exposed to 0.2 x MIC and 0.3 x MIC showed a growth rate corresponding to that of bacteria grown in the absence of penicillin. The effects of subinhibitory concentrations on streptococci previously exposed to penicillin may therefore be a more important factor in determining dosage intervals than the PAE.
在体外，用10倍最低抑菌浓度（MIC）的苄青霉素处理化脓性链球菌M12（P1800）2小时可诱导产生抗生素后效应（PAE）。发现PAE为2.4小时（范围为1.75 - 3.0小时）。在抗生素后阶段（PA阶段）的最初几个小时内，链球菌未出现3H-胸腺嘧啶核苷的掺入，这表明在此期间细菌细胞分裂受到抑制。然而，当在PA阶段加入10倍MIC的苄青霉素时，这些细菌的杀灭率与之前未接触过药物的对照培养物相同。当处于PA阶段的细菌重新暴露于浓度为0.2倍MIC的青霉素时，细菌的增殖被抑制6 - 7小时，而当浓度为0.3倍MIC时，则诱导缓慢杀灭。相比之下，之前未处理的对照暴露于0.2倍MIC和0.3倍MIC时，其生长速率与在无青霉素条件下生长的细菌相当。因此，亚抑菌浓度对先前暴露于青霉素的链球菌的影响可能是决定给药间隔的比PAE更重要的因素。
