Chalkley L J, Koornhof H J
Emergent Pathogen Research Unit, South African Medical Research Council, School of Pathology, South African Institute for Medical Research, Johannesburg.
J Antimicrob Chemother. 1988 Dec;22(6):791-800. doi: 10.1093/jac/22.6.791.
Penicillin-binding protein (PBP) patterns of penicillin-resistant laboratory-constructed transformants were compared with the PBP profiles of 26 clinical isolates of Streptococcus pneumoniae. For transformation studies DNA from a penicillin-resistant clinical isolate was used to transform a susceptible laboratory strain. Penicillin resistance was achieved in two transformation cycles. The frequency of transformation appeared to be dependent on the genetic status of the recipient used for the second transformation cross. Penicillin resistance was also attained in a single transformation round when time was allowed for full expression of random multiple transformations. PBP 2b was the first PBP to show an alteration in penicillin-binding affinity. This PBP was not easily detected in those transformants for which penicillin MICs exceeded 0.2 mg/l. The PBP profiles of the clinical isolates were complex. In addition to previously-described PBPs, new intermediate classes were demonstrated. No correlation between PBP profile and susceptibility was observed with clinical isolates except that PBP-2b exhibited molecular weight changes in moderately susceptible strains.
将青霉素耐药的实验室构建转化体的青霉素结合蛋白（PBP）模式与26株肺炎链球菌临床分离株的PBP谱进行了比较。在转化研究中，使用来自青霉素耐药临床分离株的DNA转化一株敏感的实验室菌株。在两个转化周期中实现了青霉素耐药。转化频率似乎取决于用于第二次转化杂交的受体的遗传状态。当有时间让随机多次转化充分表达时，在单个转化轮次中也获得了青霉素耐药。PBP 2b是第一个显示青霉素结合亲和力发生改变的PBP。在青霉素MIC超过0.2mg/l的那些转化体中，这种PBP不易检测到。临床分离株的PBP谱很复杂。除了先前描述的PBPs外，还发现了新的中间类别。临床分离株的PBP谱与药敏性之间未观察到相关性，除了PBP-2b在中度敏感菌株中表现出分子量变化。
