Resurgence of Mycoplasma pneumonia by macrolide-resistant epidemic clones in China

In The Lancet Microbe, Patrick M Meyer Sauteur and colleagues1Sauteur PMM Beeton ML Pereyre S et al.Mycoplasma pneumoniae: delayed re-emergence after COVID-19 pandemic restrictions.Lancet Microbe. 2023; (published online Nov 23)https://doi.org/10.1016/S2666-5247(23)00344-0Google Scholar reported about a delayed re-emergence of Mycoplasma pneumoniae after the COVID-19 pandemic restrictions. According to initial study findings, China is currently facing a concurrent outbreak of paediatric respiratory diseases, particularly the macrolide-resistant M pneumoniae (MRMP) outbreak.2Conroy G What’s behind China’s mysterious wave of childhood pneumonia?.Nature. 2023; (published online Nov 27)https://doi.org/10.1038/d41586-023-03732-wCrossref Google Scholar On the basis of more than 30 000 PCR tests and bronchoscopy findings (appendix p 3) in a paediatric hospital in east China from 2017 to 2023, we found a pronounced re-emergence of M pneumoniae, with up to 50% positive cases noted since July, 2023 (appendix p 2), compared with a lower incidence of positive cases ranging from 10% to 20% during the COVID-19 period (2020–22). We obtained 448 metagenomic datasets (appendix pp 4–11) that were derived from findings of bronchoalveolar lavage fluid samples or swabs of infected children and identified M pneumoniae in 179 samples when mapping to a reference genome (GCA_900660465.1). A phylogenetic tree was subsequently constructed and showed the presence of two primary epidemic clones in China: EC1 in P1-1 and EC2 in P1-2 (appendix pp 2, 12–20). EC1 has been isolated throughout east Asia since 2010, and is probably responsible for the elevated MRMP frequencies observed there (appendix p 2). In contrast, EC2 has recently emerged from non-resistant strains, with the first isolates identified in 2019 in Taiwan3Hsieh YC Li SW Chen YY et al.Global genome diversity and recombination in Mycoplasma pneumoniae.Emerg Infect Dis. 2022; 28: 111-117Crossref PubMed Scopus (2) Google Scholar and in 2020 in Beijing. We found that EC2 showed 100% macrolide resistance because of the acquisition of the A2063G mutation in 23S rRNA (appendix pp 2, 21). All three P1-2 strains isolated in Beijing in 2020 were derived from EC2, suggesting that EC2 could be responsible for the previously reported increase in MRMP frequencies in P1-2 strains detected in the country after 2018.4Wang X Li M Luo M et al.Mycoplasma pneumoniae triggers pneumonia epidemic in autumn and winter in Beijing: a multicentre, population-based epidemiological study between 2015 and 2020.Emerg Microbes Infect. 2022; 11: 1508-1517Crossref PubMed Scopus (5) Google Scholar Moreover, our analyses showed frequent, cryptic cross-regional M pneumoniae transmissions in both EC1 and EC2, and the Taiwan strains in 2019 showed that the EC2 MRMP strain had been spreading throughout China before 2020. PCR-based surveillance data also suggested an unusual increase in infections due to the P1-2 MRMP strain in north China from 2021 to 2022.5Jiang TT Sun L Wang TY et al.The clinical significance of macrolide resistance in pediatric Mycoplasma pneumoniae infection during COVID-19 pandemic.Front Cell Infect Microbiol. 2023; 131181402Crossref Scopus (1) Google Scholar Our findings suggest that without the restrictions enacted during the COVID-19 pandemic, the MRMP clones could have caused outbreaks across the country as early as 2020; thus, our findings provide evidence to guide future epidemic prevention and treatment in east Asia. We declare no competing interests. HL, SL, and HY contributed equally. This study was supported by grants from the National Natural Science Foundation of China (32170003, 32370099, 82202465). The funder had no role in the writing or the decision to submit this Correspondence for publication. ZC and ZZ designed the experiments. HL, SL, HY, and ZZ collected and analysed data. HL, ZC, and ZZ wrote the Correspondence. All authors reviewed and approved the report. Download .pdf (1.41 MB) Help with pdf files Supplementary appendix