Millesimo M, Savoia D
Department of Clinical and Biological Sciences, University of Torino, San Luigi Hospital, Italy.
Microbios. 1995;82(332):141-7.
In recent years an increase in severe group A streptococcal infections has been observed. The possible relation between the failure of therapy and an increase of resistance to antibiotics, which are often used for streptococcal infections (clarithromycin and erythromycin), has been assessed in vitro. Streptococcus pyogenes strains tested for susceptibility were isolated in different years from pharyngotonsillar swabs of symptomatic children and typed; another nine strains came from the American Type Culture Collection. The evaluation of antimicrobial activity demonstrated that the percentage of resistance of these bacteria to the two macrolides was 4, 4.4 and 15.5%, respectively, for strains isolated in 1990, 1991 and 1994. Clarithromycin showed a better antistreptococcal, above all bactericidal, activity. The presence of M protein in streptococci does not seem to modify the kinetic activity of the two drugs, while a slower bactericidal effect was observed against capsulated strains. The resurgence of severe group A Streptococcus infections may be due to an increase in the circulation of strains with a capsule expression, which is critical also for resistance to phagocytic killing.
近年来，已观察到A组链球菌严重感染有所增加。体外评估了治疗失败与对常用于链球菌感染的抗生素（克拉霉素和红霉素）耐药性增加之间的可能关系。对有症状儿童的咽扁桃体拭子在不同年份分离出的化脓性链球菌菌株进行药敏试验并分型；另外9株菌株来自美国典型培养物保藏中心。抗菌活性评估表明，1990年、1991年和1994年分离出的菌株对这两种大环内酯类药物的耐药百分比分别为4%、4.4%和15.5%。克拉霉素显示出更好的抗链球菌活性，尤其是杀菌活性。链球菌中M蛋白的存在似乎不会改变这两种药物的动力学活性，而对有荚膜菌株观察到杀菌作用较慢。A组链球菌严重感染的复发可能是由于有荚膜表达的菌株循环增加所致，这对抵抗吞噬杀伤也很关键。
