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

Abstract

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.

Exudative pharyngitis and Corynebacterium pseudodiphtheriticum: A case report and review of the literature

“…13,17,18 To our knowledge, three cases of exudative pharyngitis because of C. pseudodiphtheriticum have been reported to date, as summarised in Table 2. 19 ; ‡, Izurieta et al 20 ; §, Indumathi et al 21 Despite the fact that C. pseudodiphtheriticum has traditionally been described as non-toxigenic, 22 we believe confirmation of this is advisable in view of the mechanism of transmission of diphtheria toxin. Diphtheria toxin is carried on a β-phage that infects bacterial cells belonging to the species, C. diphtheriae, C. ulcerans and C. pseudotuberculosis.…”

Genomic characterization of cocirculating Corynebacterium diphtheriae and non-diphtheritic Corynebacterium species among forcibly displaced Myanmar nationals, 2017–2019

“…NDCs are considered commensal members of the healthy microflora but have gradually been recognized as emerging opportunistic pathogens capable of causing endocarditis, pneumonitis, bronchiectasis or skin infections [31][32][33][34][35][36]. Most notably, C. pseudodiphtheriticum can cause exudative pharyngitis resembling the typical toxin-mediated pseudomembrane associated with C. diphtheriae [32,[37][38][39][40], leading to clinical and laboratory diagnostic challenges, particularly during a diphtheria outbreak investigation [8]. Few genomic studies of NDC isolates have been reported and the ecology of these human-associated species, including their potential for causing disease, remains poorly understood [41,42].…”

“…pseudodiphtheriticum can cause exudative pharyngitis resembling the typical toxin-mediated pseudomembrane associated with C. diphtheriae [32, 37–40], leading to clinical and laboratory diagnostic challenges, particularly during a diphtheria outbreak investigation [8]. Few genomic studies of NDC isolates have been reported and the ecology of these human-associated species, including their potential for causing disease, remains poorly understood [41, 42].…”