Clinical features and seasonal variations in the prevalence of macrolide-resistant .

BACKGROUND

is a common pathogen causing pneumonia; macrolide-resistant strains are rapidly spreading across Japan. However, the clinical features of macrolide-resistant pneumonia have not been well established. Here, we evaluated the clinical characteristics and seasonal variations in the prevalence of with macrolide-resistant mutations (MRM).

METHODS

The monthly prevalence of MRM in strains isolated from May 2016 to April 2017 was retrospectively analyzed, and the clinical characteristics of pneumonia cases with MRM were compared to those of cases without MRM. The isolates and point mutations at site 2063 or 2064 in domain V of 23S rRNA were evaluated by the GENECUBE system and GENECUBE Mycoplasma detection kit.

RESULTS

infection was identified in 383 cases, including 221 cases of MRM (57.7%). The MRM prevalence was 86.3% (44/51) between May and July 2016, demonstrating an apparent decrease in September 2016, subsequently reaching 43.0% (34/79) in November 2016. pneumonia was diagnosed in 275 cases, including 222 pediatric and 53 adult cases. Macrolide use preceding evaluation was found to be the only feature of MRM pneumonia cases both in children (odds ratio [OR] 3.86, 95% confidence interval [CI]:1.72-8.66) and in adults (OR 7.43, 95% CI: 1.67-33.1).

CONCLUSIONS

The determination rate of MRM varied widely throughout the year, and our study demonstrated the challenges in predicting with MRM based on clinical features at diagnosis. Therefore, continuous monitoring of the prevalence of MRM is warranted, which may help in selecting an effective treatment.