Gunnison J B, Fraher M A, Pelcher E A, Jasetz E
Appl Microbiol. 1968 Feb;16(2):311-4. doi: 10.1128/am.16.2.311-314.1968.
All of the 74 strains of pneumococci isolated from human infections from 1963 to 1964 proved to be uniformly and highly susceptible to penicillin. Of these strains, 15 were identified by capsule-swelling reactions and were submitted to serial transfer in the presence of increasing concentrations of penicillin. Highly penicillin-resistant mutants were selected from 14 of the 15 strains, whereas one strain was moderately resistant. Of these mutants, 11 could still react with specific antiserum, and all of the mutants could be identified by fermentation reactions and optochin inhibition. The in vitro development of penicillin resistance in these mutants did not result in a change in cell-wall composition sufficient to diminish bile solubility. The possibility of encountering rising penicillin resistance among pneumococci, as well as the possibility that such mutants may react atypically, should be kept in mind.
1963年至1964年从人类感染中分离出的74株肺炎球菌均被证明对青霉素普遍高度敏感。在这些菌株中，有15株通过荚膜肿胀反应进行了鉴定，并在青霉素浓度不断增加的情况下进行了连续传代。从15株中的14株中筛选出了高度耐青霉素的突变体，而有1株为中度耐药。在这些突变体中，11株仍能与特异性抗血清发生反应，所有突变体均可通过发酵反应和奥普托欣抑制试验进行鉴定。这些突变体在体外对青霉素产生耐药性的过程中，细胞壁组成并未发生足以降低胆汁溶解性的变化。应牢记肺炎球菌中出现青霉素耐药性上升的可能性，以及此类突变体可能出现非典型反应的可能性。
