Outbreak Involving Macrolide-Resistant Mycoplasma pneumoniae in an Elementary School — San Francisco, California, September−December 2025
- Presentation Day/Time: Friday, April 24, 3:00 PM
- Presenter: Lydia Rautman, PhD, MPH, San Francisco Department of Public Health
The Issue
- On October 21, 2025, an elementary school notified the San Francisco Department of Public Health (SFDPH) of a large respiratory illness cluster.
What We Did
- SFDPH investigated to identify the origin and prevent additional illnesses. We sent a self-report form to teachers, students, and students' families to screen for recent or current respiratory illness and interviewed people reporting cough to collect clinical and epidemiologic information and obtain clinical specimens. Medical records for those who had sought care were reviewed.
What We Found
- We identified seven cases of laboratory-confirmed M. pneumoniae and eight more persons tested positive for a viral pathogen; however, many more were unable to be tested. In total, 47 cases of acute respiratory illness were identified, including 14 with radiographic pneumonia and one hospitalization.
What This Means
- This outbreak involving macrolide-resistant M. pneumoniae highlights resistance as an emerging public health concern that can result in treatment challenges. Surveillance of macrolide-resistant M. pneumoniae can increase resistance awareness and enhance local guidance.
