We detected a community outbreak of macrolide-resistant Mycoplasma pneumoniae infection that occurred predominantly among students at 2 schools in Yamagata, Japan.
Throat swab specimens were collected from patients who were clinically suspected to have M. pneumoniae infection after testing negative for influenza virus by a nasopharyngeal swab rapid antigen test. We performed cultures for M. pneumoniae, and all isolates were sequenced for the presence of a mutation of the 23S rRNA gene.
Of 96 specimens collected between July 2009 and January 2010, 83 were from students attending junior high school A and primary schools B, C and D. A total of 47 M. pneumoniae isolates were obtained; among them, 25, 15 and 4 were isolated from students attending schools A, B and D, respectively, and M. pneumoniae could not be isolated from students who attended school C. An A2063T mutation in domain V of the 23S rRNA gene, which is associated with macrolide resistance, was identified in 39 (83.0%) isolates. The rates of macrolide resistance at schools A, B and D were 96.0%, 86.7% and 0%, respectively. The minimum inhibitory concentrations for isolates with an A2063T transversion showed high resistance to clarithromycin (minimum inhibitory concentration, 16–64 mg/L), and clarithromycin prescribed initially was clinically ineffective.
This school-based cluster of macrolide-resistant M. pneumoniae infections, which was identified in 2 geographically close schools, indicates that the transmission principally occurred by close contact between students at school. Monitoring the spread of macrolide-resistant M. pneumoniae and clinical guidelines for the appropriate medication against such infections would be needed to control outbreaks of M. pneumoniae.
From the *Department of Microbiology, Yamagata Prefectural Institute of Public Health; †Yamanobe Pediatric Clinic; ‡Department of Laboratory Medicine, Yamagata Prefectural Central Hospital; and §Department of Infectious Diseases, Yamagata University Faculty of Medicine, Yamagata, Japan.
Accepted for publication October 23, 2012.
The authors have no funding or conflicts of interest to disclose.
Address for correspondence: Yoko Matsuzaki, MD, PhD, Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2, Yamagata 990–9585, Japan. E-mail: firstname.lastname@example.org.