Macrolide-ResistantBordetella pertussisInfection in Newborn Girl, France

Abstract A macrolide antimicrobial drug was administered to a newborn with cough. On day 23 of hospitalization, macrolide-resistant Bordetella pertussis was isolated from nasopharyngeal aspirates. DNA sequencing and PCR–restriction fragment length polymorphism showed a 2047 A-to-G mutation in the 3 copies of the 23S rRNA gene. Monitoring for macrolide resistance is essential in infants <6 months of age.