No Macrolide-Resistant Bordetella pertussis Mutations Found in Madagascar and Cambodia Pre-COVID-19

Overview

Retrospective analysis of Bordetella pertussis samples collected in Madagascar and Cambodia before the COVID-19 pandemic revealed no presence of the macrolide resistance-associated A2047G mutation. This contrasts with increasing reports of macrolide-resistant B. pertussis strains in East Asia and Europe during recent pertussis cycles.

Background

Pertussis is a highly contagious respiratory infection primarily treated with macrolide antibiotics. Resistance to macrolides, caused by the A2047G mutation in the 23s rRNA gene, has been increasingly reported in China and more recently in other countries. Surveillance of macrolide-resistant Bordetella pertussis (MRBP) strains is critical to guide treatment and control measures. The COVID-19 pandemic influenced pertussis epidemiology and antibiotic use, potentially affecting resistance patterns.

Data Highlights

Key Findings

• No macrolide-resistant A2047G mutation was detected in 55 Bordetella pertussis-positive samples from Madagascar and Cambodia collected between 2017 and 2019.
• Sequencing was successful in all but one sample from Madagascar.
• Macrolide resistance in B. pertussis remains rare outside China before the COVID-19 pandemic.
• Recent pertussis cycles (2023–2024) have shown increased MRBP detection in countries such as Finland and France, linked genetically to Chinese strains.
• Macrolide use increased during the COVID-19 pandemic, potentially increasing selective pressure for resistance emergence.
• Surveillance capacity is limited in low- and middle-income countries, underscoring the need for enhanced monitoring and sample referral systems.

Clinical Implications

Clinicians in Madagascar, Cambodia, and similar settings can currently rely on macrolides as first-line therapy for pertussis without concern for widespread resistance. However, vigilance is warranted given the global rise in MRBP strains and increased antibiotic use during the COVID-19 pandemic. Strengthening laboratory surveillance and vaccination programs is essential to prevent the emergence and spread of resistant Bordetella pertussis strains.

Conclusion

This study found no evidence of macrolide-resistant Bordetella pertussis mutations in Madagascar and Cambodia prior to the COVID-19 pandemic, highlighting regional differences in resistance prevalence. Ongoing surveillance and preventive strategies remain critical to address the evolving threat of macrolide resistance in pertussis.

References

1. He et al. 2015 -- Macrolide-resistant Bordetella pertussis in China
2. European Centre for Disease Prevention and Control 2024 -- Pertussis surveillance reports
3. WHO 2023 -- Pertussis epidemiology and vaccination
4. Nguyen et al. 2024 -- MRBP detection in France
5. Sato et al. 2024 -- MRBP in East and Southeast Asia