Fuursted K, Hjort A, Knudsen L
Department of Research and Development in Microbiology, Statens Serum Institut, Copenhagen S, Denmark.
J Antimicrob Chemother. 1997 Aug;40(2):221-6. doi: 10.1093/jac/40.2.221.
Lag of regrowth or postantibiotic effect (PAE) relates to suppression of bacterial regrowth following short exposure to an antimicrobial agent. A delay in regrowth has not yet been studied for antiseptics to any great extent. We therefore examined and compared the lag of regrowth and the bactericidal activity of five antiseptics (chloramine T, chlorhexidine, povidone-iodine, phenoxyethanol and mandelic-lactic acid) against nine bacterial pathogens. Delay in regrowth was determined by application of two concentration-time schedules: a test concentration at the MBC with a contact time of 1 h or using fixed suboptimum concentration of each antiseptic for 2 min (optimum concentrations sterilized the culture, impeding assessment of regrowth) followed by a neutralization-dilution step and subsequent viable counting to follow bacterial regrowth. Each antiseptic displayed a different spectrum of activity in terms of MIC or MBC, bactericidal effect and lag of regrowth. The delay in regrowth varied from 0 to 5.7 h with only a few discrepancies between the two treatment schedules. Mandelic-lactic acid and chloramine T induced a significantly longer lag as compared with the other agents, whereas phenoxyethanol produced the shortest lag values. No significant correlation between the killing rate and the lag of regrowth could be demonstrated. Information on bactericidal activity, as well as lag of regrowth, could be a useful screening method for the efficacy of antiseptics. Moreover, data on lag of regrowth could contribute to the choice of antiseptic and guide in determining the optimum interval between repeated applications of antiseptics.
再生长延迟或抗生素后效应（PAE）与短时间接触抗菌剂后细菌再生长的抑制有关。对于防腐剂的再生长延迟尚未进行广泛研究。因此，我们检测并比较了五种防腐剂（氯胺T、氯己定、聚维酮碘、苯氧乙醇和扁桃酸-乳酸）对九种细菌病原体的再生长延迟和杀菌活性。通过应用两种浓度-时间方案来确定再生长延迟：MBC的测试浓度，接触时间为1小时；或使用每种防腐剂的固定亚最佳浓度2分钟（最佳浓度会使培养物灭菌，妨碍对再生长的评估），随后进行中和-稀释步骤并进行后续活菌计数以跟踪细菌再生长。每种防腐剂在MIC或MBC、杀菌效果和再生长延迟方面表现出不同的活性谱。再生长延迟在0至5.7小时之间变化，两种处理方案之间只有少数差异。与其他试剂相比，扁桃酸-乳酸和氯胺T诱导的再生长延迟明显更长，而苯氧乙醇产生的再生长延迟最短。杀菌率与再生长延迟之间未显示出显著相关性。关于杀菌活性以及再生长延迟的信息可能是一种有用的防腐剂功效筛选方法。此外，再生长延迟的数据可能有助于选择防腐剂，并指导确定重复应用防腐剂的最佳间隔时间。
