Children with Mycoplasma pneumoniae infection in Taiwan: Changes in molecular characteristics and clinical outcomes

Background: Mycoplasma pneumoniae is a pathogen that causes respiratory diseases in children. Infections caused by M. pneumoniae are usually self-limited but occasionally can be severe. We observed emerging cases of severe mycoplasma infection requiring extracorporeal membrane oxygenation (ECMO). Thus, we investigated chronological changes in the molecular features of the M. pneumoniae and its clinical impacts among the pediatric population. Methods: From 2011 to 2019, respiratory samples were collected from patients younger than 18 years old with pneumonia in a tertiary children's hospital. Focused multiple-locus variable number of tandem repeats analysis (MLVA) typing was performed on samples positive for M. pneumoniae in 2016 and 2019. Clinical data from the patients' electronic medical records were collected. We described the annual trend of macrolide resistance and MLVA type and analyzed the associations between clinical manifestations and MLVA types. Results: The percentage of macrolide-resistant (MLR) M. pneumoniae gradually increased from 22% (27/122) in 2015 to 70% (82/117) in 2019. Among the MLR M. pneumoniae, the predominant strain shifted from type P (31% [13/42]) to type A (40% [19/46]). The demographics, initial presentations, and clinical courses of the subjects with MLR M. pneumoniae did not differ significantly between 2011 and 2019. However, in 2019, two fulminant cases requiring venovenous ECMO were observed, which indicates that more attention to the clinical severity of MLR M. pneumoniae infections is warranted. Conclusion: Obtaining accurate information on macrolide susceptibility is crucial for physicians to initiate appropriate antibiotic treatment in a timely fashion. Although we could not identify significant differences among mycoplasma pneumonias caused by different MLVAs over a span of 9 years, the emergence of severe mycoplasma infections requiring ECMO was clinically significant, and further monitoring was required.