---
title: "Post–COVID-19 Surge of Macrolide-Resistant Mycoplasma pneumoniae ST3 Subclades in Taiwanese Childr"
id: "cdc-emerging-infectious-diseases-journal-1-emergence-of-novel-macrolide-resistant-mycoplasma-pneumoniae-sequence-type-3"
canonical_url: "https://medichelpline.com/clinical-feed/cdc-emerging-infectious-diseases-journal-1-emergence-of-novel-macrolide-resistant-mycoplasma-pneumoniae-sequence-type-3"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "CDC Emerging Infectious Diseases Journal"
source_url: "https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article"
published_at: "2026-10-14T04:00:00.000Z"
evidence_level: "Agency Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Post–COVID-19 Surge of Macrolide-Resistant Mycoplasma pneumoniae ST3 Subclades in Taiwanese Childr
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/cdc-emerging-infectious-diseases-journal-1-emergence-of-novel-macrolide-resistant-mycoplasma-pneumoniae-sequence-type-3
- **Specialty:** [Infectious Disease](https://medichelpline.com/clinical-feed/infectious-disease.md)
- **Primary Source:** CDC Emerging Infectious Diseases Journal
- **Source URL:** [Original Journal Publication](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article)
- **Published At:** 2026-10-14T04:00:00.000Z
- **Evidence Rating:** Agency Feed
## Executive GIST (TL;DR)
- The multicenter study used Chang Gung Memorial Hospital (CGMH) laboratory surveillance across four branches to estimate pediatric **Mycoplasma pneumoniae** incidence and severe outcomes from 2017–2024. - Incidence and severity increased markedly after the COVID-19 pandemic: 2024 incidence doubled versus the 2019 peak, reaching 546/100,000 population; **ICU** admissions rose 2.2-fold to 10.9/100,000; CNS complications rose 13.7-fold to 6.1/100,000. - A prospective 2023–2024 cohort (n = 226) identified independent **ICU** risk factors: neutrophils >7,000/µL (aOR 6.2), platelets >400×10^3/µL (aOR 12.5), pleural effusion (aOR 9.7), and CNS involvement (aOR 27.9). - Laboratory case confirmation relied on real-time PCR and, from 2019, the BioFire FilmArray; CNS cases required PCR detection in respiratory or CSF samples and absence of alternative etiologies. - Culture, multilocus sequence typing (MLST), and 23S rRNA gene PCR were performed for isolates; the source reported phylogenetic analysis of 698 genomes. - Phylogenetics showed four emerging ST3 subclades replaced pre–COVID-19 lineages by mid-2024; one subclade associated with severe outcomes, and macrolide resistance remains prevalent in Taiwan (prepandemic rates ≈70%). - CSF and serum paired testing for IgG and albumin was performed and CSF IgG index calculated; the source provided the formula but did not report numeric index thresholds for clinical interpretation in all cases. - The study authors called for enhanced surveillance because of evolving resistant, neurotropic lineages; the source did not report therapy details, specific MIC distributions in the text provided here, nor full demographic breakdowns beyond cohort inclusion criteria.
## Clinical Analysis & Structured Key Points
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[EID Journal](https://wwwnc.cdc.gov/eid/) 2. [Volume 32](https://wwwnc.cdc.gov/eid/early-release) 3. [Early Release](https://wwwnc.cdc.gov/eid/early-release#issue-1347) 4. [Main Article](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) * [Facebook](https://www.facebook.com/sharer/sharer.php?u=%2Feid%2Farticle%2F32%2F11%2F26-0439_article "Share to Facebook") * [Twitter](http://twitter.com/share?url=%2Feid%2Farticle%2F32%2F11%2F26-0439_article&text= "Share to Twitter") * [LinkedIn](https://www.linkedin.com/shareArticle?url=%2Feid%2Farticle%2F32%2F11%2F26-0439_article&title= "Share to LinkedIn") * [Syndicate](https://tools.cdc.gov/medialibrary/index.aspx#/sharecontent//eid/article/32/11/26-0439_article "Embed this Page") [ Emerging Infectious Disease journal ISSN: 1080-6059 ](https://wwwnc.cdc.gov/eid/) _Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released._ #### Volume 32, Number 11—November 2026 ##### _Research_ ### Emergence of Novel Macrolide-Resistant _Mycoplasma pneumoniae_ Sequence Type 3 Subclades in Children after COVID-19 Pandemic, Taiwan On This Page [Materials and Methods](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) * * * [Results](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) * * * [Discussion](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) * * * [Suggested Citation](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) Figures [Figure 1](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-f1) * * * [Figure 2](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-f2) * * * [Figure 3](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-f3) * * * [Figure 4](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-f4) Tables [Table 1](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-t1) * * * [Table 2](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-t2) * * * [Table 3](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-t3) Downloads [Appendix 1 ](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-app1.pdf) * * * [Appendix 2 ](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-app2.xlsx) * * * [RIS [TXT - 2 KB] ](https://wwwnc.cdc.gov/eid/article/32/11/26-0439.ris) Article Metrics [Metric Details](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article) Related Articles [Metastatic _Candidozyma auris_ Infection](https://wwwnc.cdc.gov/eid/article/32/11/26-0984_article) * * * [Five-Biomarker Definition for hvKp](https://wwwnc.cdc.gov/eid/article/32/11/26-0825_article) * * * [Multidrug-Resistant _Salmonella_ Typhi, West Africa](https://wwwnc.cdc.gov/eid/article/32/10/26-0813_article) * * * [More articles on Antimicrobial Resistance](https://wwwnc.cdc.gov/eid/spotlight/antimicrobial-resistance) Yu-Chia Hsieh, Chen-Ching Lin, Jia-Wen Wu, Yi-Hsuan Liu, Yi-Jiun Pan, Tzu-Ya Lo, Shian-Sen Shie, Huey-Ling You, Chong-Wei Huang, Yi-Chuan Huang, Tzu-Ching Huang, Yu-Xin She, Yin-Cheng Chen[1](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#fn1), and Shiao-Wen Li[1](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#fn1)[![Comments to Author](https://wwwnc.cdc.gov/eid/content/images/icon/email.gif)](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#comment) Author affiliation: Chang Gung Children’s Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan (Y.-C. Hsieh, J.-W. Wu, Y.-H. Liu, T.-Y. Lo); School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (C.-C. Lin, Y.-C. Chen); School of Medicine, College of Medicine, People’s Republic of China Medical University, Taichung, Taiwan (Y.-J. Pan); Chang Gung Memorial Hospital, Taoyuan (S.-S. Shie); Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan (H.-L. You); Keelung Chang Gung Memorial Hospital, Keelung, Taiwan (C.-W. Huang, Y.-C. Huang); School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei (T.-C. Huang); College of Science Department of Life Sciences, National University of Kaohsiung, Kaohsiung (Y.-X. She, S.-W. Li) [Suggested citation for this article](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#suggestedcitation) ### Abstract Post–COVID-19 pandemic _Mycoplasma pneumoniae_ resurgences have occurred globally and have been particularly severe in Taiwan. We conducted a multicenter study to assess _M. pneumoniae_ trends in children. Compared with the 2019 peak, 2024 data revealed a doubling of incidence (546/100,000 population), a 2.2-fold increase in intensive care unit admissions (10.9/100,000 population), and a 13.7-fold surge in central nervous system complications (6.1/100,000 population). In a 2023–2024 prospective cohort (n = 226), intensive care unit admission risk factors were neutrophils >7,000/μL (adjusted odds ratio [aOR] 6.2 [95% CI 1.3–29.9]), platelets >400 × 103/μL (aOR 12.5 [95% CI 2.7–57.9]), pleural effusion (aOR 9.7 [95% CI 1.6–58.1]), and central nervous system involvement (aOR 27.9 [95% CI 4.1–188.3]). Phylogenetic analysis of 698 genomes demonstrated that 4 emerging subclades replaced pre–COVID-19 lineages by mid-2024; 1 subclade was associated with severe outcomes, highlighting evolving resistant, neurotropic lineages and calling for enhanced surveillance. After the height of the COVID-19 pandemic, _Mycoplasma pneumoniae_ respiratory infections did not reemerge as quickly as influenza or respiratory syncytial virus did, likely because of the pathogen’s long incubation period, long periodicity, and slow growth rate ([_1_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r1 "1")). _M. pneumoniae_ activity increased markedly in mid-2023, leading to unprecedented epidemics and varying disease severity across multiple countries worldwide. In parts of Europe and the United States, where macrolide resistance remains [External Link](https://www.biomerieux.com)). For patients with suspected CNS involvement, CSF samples were tested using real-time PCR. We used data from the National Health Insurance system to estimate the population sizes served by the 4 CGMH branches and then calculated the annual and monthly incidence of _M. pneumoniae_ infection. We conducted medical chart reviews to record the diagnosis, hospitalization, ICU admission, and _M. pneumoniae_ –related CNS complications, defined as neurologic syndromes occurring in association with _M. pneumoniae_ infection, confirmed by PCR detection of _M. pneumoniae_ in respiratory or CSF samples, and in the absence of an alternative etiology ([_11_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r11 "11")). Included manifestations were isolated encephalopathy, encephalitis, brainstem or basal ganglia encephalitis, acute disseminated encephalomyelitis, cerebellitis, Guillain–Barré syndrome, and transverse myelitis. In children demonstrating CNS complications, paired CSF and serum samples were collected on the same day. Paired CSF and serum IgG and albumin concentrations were measured using commercial ELISA kits according to the manufacturer’s instructions. The CSF IgG index was calculated using the followings formula: ![](https://wwwnc.cdc.gov/eid/images/26-0439-formula.jpg) Patients with Risk Factors for ICU Admission For the second primary objective, we extended a previously initiated prospective study that enrolled children <18 years of age with laboratory-confirmed _M. pneumoniae_ infection at CGMH during 2023–2024 ([_10_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r10 "10")). We excluded children with chronic lung disease, genetic or metabolic disorders, neurologic disease, immunodeficiency, or cancer. Diagnosis required compatible clinical features and confirmation by PCR or culture ([_10_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r10 "10")). For clinically suspected cases, attending physicians obtained throat swab specimens and forwarded them to the CGMH–Linkou central laboratory, after written informed consent had been secured from patients or their legal guardians. We performed DNA extraction and PCR targeting the 23S rRNA gene as described previously ([_10_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r10 "10")). We performed multilocus sequence typing (MLST) using the _M. pneumoniae_ PubMLST scheme and assigned sequence type (ST) according to the allelic profiles of 8 loci ([Appendix 1](https://wwwnc.cdc.gov/eid/article/32/11/26-0439-app1.pdf)). We recorded demographic, clinical, and laboratory variables prospectively in a standardized case-report form. We defined severe _M. pneumoniae_ infection as admission to an ICU. ##### Isolation of _M. pneumoniae_ and Determination of MICs Oropharyngeal swab, pleural fluid, and CSF samples were collected from pediatric patients and cultured as previously described ([_10_](https://wwwnc.cdc.gov/eid/article/32/11/26-0439_article#r10 "10")). For patients with respiratory infection, culture was performed when respiratory specimens were PCR-positive for _M. pneumoniae_. When CNS involvement occurred
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