# P-460. Clinical Presentations and Outcomes of Pediatric Mycoplasma pneumoniae: A Retrospective Chart Review

## TL;DR

This study examines the resurgence of Mycoplasma pneumoniae in hospitalized children, highlighting extrapulmonary symptoms and treatment challenges.

## Contribution

The study documents a significant increase in M. pneumoniae cases and emphasizes the importance of serology for diagnosing extrapulmonary manifestations.

## Key findings

- There was a 20.7-fold increase in M. pneumoniae cases in 2024 compared to 2023.
- 21% of patients had isolated extrapulmonary involvement, with many being PCR-negative but serology-positive.
- 23% of patients treated with macrolides showed no clinical response, requiring alternative antibiotics.

## Abstract

Mycoplasma pneumoniae causes a self-resolving illness in children, but it can also cause severe illness requiring hospitalization. Cases fell during the COVID-19 pandemic, but then surged in Asia in late 2023 and spread globally in 2024. This study aimed to characterize presentations, diagnostic challenges, and outcomes for hospitalized children with confirmed M. pneumoniae infections over 12 months.

A retrospective cohort study was conducted at Riley Hospital for Children of all patients admitted to pediatric units with confirmed M. pneumoniae infection from February 2024 to February 2025. Inclusion required a positive PCR of nasopharyngeal swab, bronchoalveolar lavage, or cerebrospinal fluid; a multiplex respiratory panel; or serology. Demographics, comorbidities, clinical presentations, diagnostic workup, treatment regimens, and outcomes were extracted to REDCap. A comparative analysis was done using data from February 2023 to January 2024.

Analysis identified 122 clinical encounters with 148 positive tests. There were 112/2573 (4.35%) positive molecular respiratory tests for M. pneumoniae, a 20.7-fold increase from the prior 12 months (5/2363; 0.21%), Figure 1. The mean age was 10.0 years (range 1 month-25 years), with 25 (20.3%) under 5 years old. An overview of presentations and M. pneumoniae PCR and serologic test results is available in Table 1. Notable findings include that 26 (21%) patients had isolated extrapulmonary (EP) involvement. Of isolated EP cases, 54% dermatologic and 33% CNS cases were PCR-negative but serology-positive. Viral coinfections were present in 22 cases (18%).

Intensive care unit (ICU) admission was needed for 28 cases (25%), mainly for pulmonary complications (23/28, 82%). Macrolides were given to 91 patients (75%), but 28 (23%) exhibited clinical non-response, requiring escalation to doxycycline or fluoroquinolone. One death occurred (0.8%).

This study highlights a resurgence of pediatric M. pneumoniae infections in 2024–2025, Extrapulmonary manifestations, especially dermatologic and CNS, were frequent and often PCR-negative, reinforcing the need for serologic testing. Clinicians should be aware of atypical Mycoplasma presentations, diagnostic limitations, and treatment resistance patterns.

All Authors: No reported disclosures