Gutmann L, Tomasz A
Antimicrob Agents Chemother. 1982 Jul;22(1):128-36. doi: 10.1128/AAC.22.1.128.
Penicillin-resistant and penicillin-tolerant mutants have been isolated from group A streptococci mutagenized by ethyl methane sulfonate. The resistant mutants had an elevated minimal growth inhibitory concentration for benzylpenicillin (minimal inhibitory concentration, 0.2 microgram/ml, as compared with the minimal inhibitory concentration of 0.006 microgram/ml in the penicillin-susceptible parent strain); they also had an abnormal cellular morphology and showed altered penicillin-binding proteins. Penicillin-tolerant mutants were killed more slowly than were the parental cells during treatment with penicillin; they had virtually unchanged minimal inhibitory concentration values for penicillin and normal cellular morphology and penicillin-binding proteins.
已从经甲磺酸乙酯诱变的A组链球菌中分离出耐青霉素和对青霉素耐受的突变体。耐药突变体对苄青霉素的最低生长抑制浓度升高（最低抑菌浓度为0.2微克/毫升，而青霉素敏感亲本菌株的最低抑菌浓度为0.006微克/毫升）；它们还具有异常的细胞形态，并显示出青霉素结合蛋白发生改变。在青霉素处理期间，耐青霉素突变体的死亡速度比亲本细胞慢；它们对青霉素的最低抑菌浓度值几乎没有变化，并且细胞形态和青霉素结合蛋白正常。
