Non-toxigenic Corynebacterium diphtheriae endocarditis: A cluster of five cases

• Published in: Southern African journal of infectious diseases Vol. 39; no. 1; pp. 539 - e7
• Main Authors: Lovelock, Tamsin, du Plessis, Mignon, van der Westhuizen, Clinton, Janson, Jacques T, Lawrence, Charlene, Parker, Arifa, Pecoraro, Alfonso, Prozesky, Hans, von Gottberg, Anne, Taljaard, Jantjie
• Format: Journal Article
• Language: English
• Published: South Africa African Online Scientific Information Systems (Pty) Ltd t/a AOSIS 2024; AOSIS
• Subjects: Bacterial proteins; Cloxacillin; Development and progression; Endocarditis; Epidemiology; Genomics; Health aspects; Infection; infective endocarditis; non-toxigenic corynebacterium diphtheriae; Original Research; outbreak; Penicillin G; Vaccination; Vaccines; Virulence (Microbiology); South Africa; non-toxigenic Corynebacterium diphtheriae; outbreak; infective endocarditis
• ISSN: 2312-0053; 2313-1810
• DOI: 10.4102/sajid.v39i1.539

Classical toxin-mediated respiratory diphtheria has become less common because of widespread effective vaccination globally but invasive disease as a result of non-toxigenic strains of is not prevented by vaccination and may result in severe disease, including infective endocarditis (IE). To describe the outbreak and subsequent investigation of a cluster of five cases of non-toxigenic endocarditis. A retrospective observational case series of five cases of non-toxigenic endocarditis identified in the rural West Coast district of the Western Cape province of South Africa between May 2021 and June 2021. Non-toxigenic IE had an aggressive clinical course with high mortality in this cohort. Only one of five patients survived to hospital discharge. The surviving patient received a prompt diagnosis with early surgical intervention but still had a complicated clinical course. Notably, only one case had a pre-existing risk factor for IE, namely a prosthetic valve. Whole genome sequencing of clinical isolates confirmed that all isolates were of the same novel sequence type of non-toxigenic but despite a thorough investigation no epidemiological link was ever found between the cases. Non-toxigenic strains of are less well known but may be highly virulent and cause severe invasive disease. This is the largest cluster of non-toxigenic IE ever described in South Africa and expands the body of literature on this unusual but possibly emerging infection.