Evolving antibiotic resistance in Group B Streptococci causing invasive infant disease: 1970-2021.

Group B streptococcal strains isolated from infants with invasive infection have become more resistant to second-line antibiotics over time. In this epidemiologic study of 2017 group B streptococci isolated from 1970 to 2021, penicillin susceptibility remained uniform; however, resistance to erythromycin and clindamycin increased significantly over time across all capsular serotypes. Clindamycin resistance exceeded 20% by 2010 in most serotypes. While penicillin remains the treatment of choice for group B streptococcal infant disease, pediatricians and neonatologists should be aware of the high prevalence of resistance to clindamycin, a recommended alternative drug used for intrapartum-antibiotic prophylaxis in penicillin-allergic women.