Evolving cluster of severe infective endocarditis with non-toxigenic C. diphtheriae involving people experiencing homelessness and people with substance misuse

The UKHSA are currently investigating reports of non-toxigenic C. diphtheriae presenting with severe, fulminant infective endocarditis (IE). Initial case finding has identified 5 cases with onsets from July 2024 to the present date. The majority are young males (30 median; range 23–52 years) with a history of inhalation, smoking or nasal insufflation of heroin or crack cocaine/powdered cocaine. All cases report no intravenous drug use (IVDU), although one acknowledged past use. A significant proportion (60%) have been street homeless in London, although single cases are noted to be resident in the East of England and South-East England.

Cases had rapid disease progression with large vegetations and marked tissue destruction requiring valvular surgery and multiple embolic episodes despite appropriate intravenous antibiotic therapy. One case has died.