A two-case cluster of toxigenic Corynebacterium diphtheriae with molecular linkage

Shabhina Baghauan^1*, Marlene Yin Zin lng², Yii Ling Liow^1,5, Nurulyumni Faraha Md Sharizam¹, Nur Afiza Aziz¹, Yaminie Nair Madhavan¹, Siti Fatimah Zahara Nor Rosli², Noraida Khalid³, Habib Abdul Hakim Esa⁴

1. Microbiology Unit, Department of Pathology, Hospital Sultanah Aminah, Jalan Persiaran Abu Bakar Sultan, 80100, Johor Bahru, Malaysia.

2. Emergency and Trauma Department, Hospital Sultanah Aminah, Jalan Persiaran Abu Bakar Sultan, 80100, Johor Bahru, Malaysia.

3. Forensic Department, Hospital Sultanah Aminah, Jalan Persiaran Abu Bakar Sultan, 80100 Johor Bahru, Malaysia. 

4. Unit of Bacteriology, Infectious Disease Research Center, Institute for Medical Research, National Institutes of Health (NIH), Seksyen U13 Setia Alam, 40170, Shah Alam, Malaysia.

5. Clinical Research Centre (CRC) Unit, Hospital Sultanah Aminah, Jalan Persiaran Abu Bakar Sultan, 80100, Johor Bahru, Malaysia.

*Corresponding author: Shabhina Baghauan, This email address is being protected from spambots. You need JavaScript enabled to view it.

CITATION: Baghauan, S., Ing, M. Y. Z., Ling Liow, Y., Md Sharizam, N. F., Aziz, N. A., Madhavan, Y. N., Rosli, S. F. Z. N., Khalid, N., & Esa, H. A. H. (2026). A two-case cluster of toxigenic Corynebacterium diphtheriae with molecular linkage. International Medical Research Journal, 12(1), 107–117. https://doi.org/10.63719/imrj.2026.12.01.009

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ABSTRACT

Diphtheria is a vaccine-preventable disease that continues to cause sporadic outbreaks in Malaysia, particularly among under-immunised populations. We report two temporally linked cases of toxigenic Corynebacterium diphtheriae presenting to a tertiary hospital in southern Malaysia. The first involved a 44-year-old adult male who was brought in deceased with extensive upper airway pseudomembrane formation. Two days later, a four-month-old infant presented with severe respiratory distress and required intensive care. Microbiological investigations confirmed toxigenic C. diphtheriae in both cases. The temporal clustering of these cases raised the possibility of an epidemiological association between them. Molecular typing using pulsed-field gel electrophoresis (PFGE) demonstrated indistinguishable strain profiles, implying circulation of a common strain and a possible shared source. These cases highlight the continued clinical relevance of diphtheria and the role of molecular methods in identifying strain linkage. Early recognition, strict infection prevention measures, and sustained vaccination coverage remain critical to preventing morbidity, mortality, and secondary transmission.

KEYWORDS: Corynebacterium diphtheriae, Diphtheria, Molecular epidemiology, Infection prevention and control