# Localized Outbreak of Macrolide-Resistant Pertussis in Infants, Japan, March–May 2025

**Authors:** Takafumi Obara, Kyoko Kano, Takashi Yorifuji, Kohei Tsukahara, Naoki Yogo, Yuichiro Muto, Tetsuya Yumoto, Hiromichi Naito, Atsunori Nakao, Katsuki Hirai

PMC · DOI: 10.3201/eid3201.250824 · Emerging Infectious Diseases · 2026-01-01

## TL;DR

A pertussis outbreak in Japan affected unvaccinated infants, with some cases showing resistance to macrolide antibiotics.

## Contribution

The study reports a localized outbreak of macrolide-resistant pertussis in infants and emphasizes the need for vaccination and resistance monitoring.

## Key findings

- Ten unvaccinated infants were affected in Kumamoto, Japan, between March and May 2025.
- Six infants had confirmed macrolide-resistant Bordetella pertussis infections.
- Nine infants required intensive care, underscoring the severity of the outbreak.

## Abstract

A localized pertussis outbreak involving 10 unvaccinated infants occurred in Kumamoto, Japan, during March–May 2025. Nine infants were admitted to the pediatric intensive care unit, 6 of whom received a confirmed diagnosis of macrolide-resistant Bordetella pertussis infection. This outbreak highlights the importance of booster vaccinations and resistance surveillance.

## Linked entities

- **Diseases:** pertussis (MONDO:0005077)
- **Species:** Bordetella pertussis (taxon 520)

## Full-text entities

- **Diseases:** Leukocytosis (MESH:D007964), infected (MESH:D007239), diphtheria (MESH:D004165), bacterial infection (MESH:D001424), Infectious Diseases (MESH:D003141), respiratory failure (MESH:D012131), neurologic sequelae (MESH:D009422), Bordetella pertussis infection (MESH:D014917), ventilator-associated pneumonia (MESH:D053717), critical illness (MESH:D016638), neuromuscular blockade (MESH:D020879), pulmonary hypertension (MESH:D006976), COVID-19 (MESH:D000086382), tetanus (MESH:D013746), paroxysmal coughing (MESH:D003371), bradycardia (MESH:D001919)
- **Chemicals:** ampicillin (MESH:D000667), ampicillin/sulbactam (MESH:C035444), Macrolide (MESH:D018942), MRBP (-), nitric oxide (MESH:D009569), erythromycin (MESH:D004917), TMP/SMX (MESH:D015662), azithromycin (MESH:D017963)
- **Species:** Homo sapiens (human, species) [taxon 9606], Bordetella pertussis (species) [taxon 520]
- **Mutations:** A2047G

## Full text

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## Figures

1 figure with captions in the complete paper: https://tomesphere.com/paper/PMC12870018/full.md

## References

10 references — full list in the complete paper: https://tomesphere.com/paper/PMC12870018/full.md

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Source: https://tomesphere.com/paper/PMC12870018