Diphtheria-like illness in a fully immunised child caused by Corynebacterium pseudodiphtheriticum

Corynebacterium pseudodiphtheriticum is a common commensal flora of the upper respiratory tract in humans. Though the pathogenicity of C. pseudodiphtheriticum is not rare, its role as an opportunistic pathogen is mainly limited to the lower respiratory tract, particularly in patients with underlying systemic conditions or immune-compromisation. We hereby present the first case of C. pseudodiphtheriticum causing diphtheria-like illness affecting the upper respiratory tract of a 6-year-old fully immunised otherwise healthy child. In countries with very low incidence of diphtheria, C. pseudodiphtheriticum should be included in differential diagnosis for a child presenting with diphtheria-like illness. Simple, rapid screening tests should be used to differentiate it from C. diphtheriae and hence, to prevent unnecessary concern in community.