青霉素和克林霉素对A组β溶血性链球菌荚膜表达的体外和体内作用
In vitro and in vivo effects of penicillin and clindamycin on expression of group A beta-hemolytic streptococcal capsule.
作者信息
Brook I, Gober A E, Leyva F
机构信息
Department of Pediatrics, Georgetown University School of Medicine, Washington, D.C., USA.
出版信息
Antimicrob Agents Chemother. 1995 Jul;39(7):1565-8. doi: 10.1128/AAC.39.7.1565.
Encapsulation of group A beta-hemolytic streptococci (GABHS) is an important virulence factor. The changes that occur in the frequency of encapsulation of GABHS during pharyngotonsillitis, in 20 patients treated with penicillin and 20 treated with clindamycin, were investigated. The effects of subinhibitory concentrations of these agents were also evaluated in vitro. At day 4, 8 of 10 (80%) GABHS isolates recovered from children treated with penicillin were encapsulated, compared with 1 of 5 (20%) of those from children treated with clindamycin (P < 0.05). Two days following 10 days of therapy, GABHS was eliminated from 13 of the 20 (65%) children treated with penicillin and from all treated with clindamycin (P < 0.05). At that time, six of the seven GABHS isolates recovered in patients treated with penicillin were encapsulated. GABHS were not detected after 4 days of therapy in those treated with clindamycin. Incubation of GABHS isolates with one-half of the MIC of clindamycin reduced the frequency of encapsulation, compared with that after incubation with one-half of the MIC of penicillin (12.5 versus 67.5%). These data illustrate the superiority of clindamycin over penicillin in reducing the expression of a capsule by GABHS.
A组β溶血性链球菌（GABHS）的荚膜形成是一种重要的毒力因子。对20例接受青霉素治疗和20例接受克林霉素治疗的咽炎扁桃体炎患者，研究了GABHS荚膜形成频率在治疗过程中的变化。还在体外评估了这些药物亚抑菌浓度的作用。在第4天，从接受青霉素治疗的儿童中分离出的10株GABHS中有8株（80%）形成荚膜，而从接受克林霉素治疗的儿童中分离出的5株中有1株（20%）形成荚膜（P<0.05）。治疗10天后的第2天，20例接受青霉素治疗的儿童中有13例（65%）的GABHS被清除，而所有接受克林霉素治疗的儿童中的GABHS均被清除（P<0.05）。此时，在接受青霉素治疗的患者中分离出的7株GABHS中有6株形成荚膜。接受克林霉素治疗的患者在治疗4天后未检测到GABHS。与用青霉素MIC的一半孵育后相比，用克林霉素MIC的一半孵育GABHS分离株可降低荚膜形成频率（12.5%对67.5%）。这些数据表明克林霉素在降低GABHS荚膜表达方面优于青霉素。
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