Penicillin is again the agent of choice for secondary prophylaxis, but sulfadiazine or a macrolide or azalide are acceptable alternatives in penicillin-allergic individuals.

• 盘尼西林仞是首选药物，对盘尼西林过敏的可以选择磺胺嘧啶、大环内酯类或氮杂内酯类。