A localized pertussis outbreak involving 10 unvaccinated infants occurred in Kumamoto, Japan, during March-May 2025. Nine infants were admitted to the pediatric intensive care unit, 6 of whom received a confirmed diagnosis of macrolide-resistant Bordetella pertussis infection. This outbreak highlights the importance of booster vaccinations and resistance surveillance.
Keywords: Japan; antimicrobial resistance; bacteria; drug resistance; infants; macrolides; newborns; outbreak; pertussis.