Yourassowsky E, Van der Linden M P, Lismont M J, Crokaert F
J Antimicrob Chemother. 1983 Apr;11(4):333-8. doi: 10.1093/jac/11.4.333.
The growth curve patterns of 8 strains of Escherichia coli exposed to amoxycillin or ampicillin were studied in the MS-2 system, which allows an accurate comparison over a wide range of concentrations. The early response (the first 2 h) of the growth curve showed residual growth (increase in OD before lysis) after the introduction of the antibiotics. The maximal value of this residual growth (MRVG) was measured for ampicillin and amoxycillin concentrations from 1 to 500 mg/l. The rate of regrowth in the post antibiotic period was studied by the use of beta-lactamase to eliminate the penicillins. In these experimental conditions the following observations were made: (a) the MVRG dropped more rapidly in amoxycillin-treated than in ampicillin-treated cultures. This effect was observed at concentrations from twice the MIC to 500 mg/l, despite the fact that some strains have a lower susceptibility to amoxycillin in terms of MIC values. (b) neutralization of antibiotic by beta-lactamase caused a longer lag of regrowth in amoxycillin-treated cultures than in ampicillin-exposed cultures.
在MS-2系统中研究了8株暴露于阿莫西林或氨苄西林的大肠杆菌的生长曲线模式，该系统能够在很宽的浓度范围内进行准确比较。生长曲线的早期反应（最初2小时）显示，在引入抗生素后出现了残留生长（裂解前OD增加）。测定了氨苄西林和阿莫西林浓度为1至500 mg/l时这种残留生长的最大值（MRVG）。通过使用β-内酰胺酶消除青霉素来研究抗生素后时期的再生长速率。在这些实验条件下，观察到以下情况：(a) 阿莫西林处理的培养物中MRVG下降比氨苄西林处理的培养物更快。在浓度从MIC的两倍到500 mg/l时观察到这种效应，尽管有些菌株就MIC值而言对阿莫西林的敏感性较低。(b) β-内酰胺酶对抗生素的中和导致阿莫西林处理的培养物中再生长的延迟比氨苄西林暴露的培养物更长。
