Regional Differences in Prevalence of Macrolide Resistance among Pediatric Mycoplasma pneumoniae Infections in Hokkaido, Japan

: Recently, macrolide-resistant (MR) Mycoplasma pneumonia appeared, and prevalence of macrolide resistance among M. pneumoniae infections varies by country. However, reports on regional differences in the prevalence of MR M. pneumonia within a country are scarce. In this study, 617 nasopharyngeal swab samples were collected from 617 pediatric patients, and DNA of M. pneumoniae was identified in 95 samples. In 51 of the 95 M. pneumonia positive samples, we detected the presence of mutation A2063G mutation (conferring macrolide resistance) in the 23S rRNA gene. The overall macrolide resistance rate was 53.7%, but there were regional differences: 0.0% in Muroran, 5.3% in Asahikawa, 55.3% in Sapporo, and 100.0% in Kushiro. Statistically significant pairwise differences in the prevalence of MR M. pneumoniae were observed among these cities except for the pair of Muroran and Asahikawa. After exclusion (in order to avoid the influence of macrolides) of patients who were prescribed macrolides before collection of nasopharyngeal swab samples, statistically significant differences persisted: 0.0% in Muroran, 5.6% in Asahikawa, 38.5% in Sapporo, and 100.0% in Kushiro.