Infections with Corynebacterium diphtheriae: six years' experience at an inner London teaching hospital.

Recently, a preponderance of non-toxigenic strains of Corynebacterium diphtheriae has been reported, as has the broadening spectrum of disease caused by these strains. This study presents data on 85 isolates of C. diphtheriae over a six year period (1998-2003). Eighty were non-toxigenic isolates from patients with sore throat, and five (one toxigenic) were from cutaneous ulcers in travellers returning from endemic areas. When examined in relation to denominator data provided by the Health Protection Agency (HPA) for the whole of England and Wales, 1998-2002, 75% of all notifications of C. diphtheriae for England and Wales originated from the laboratories at University College London Hospitals (UCLH). In some years (1999 and 2001) 95-100% of isolates came from UCLH. We believe that national data do not reflect true incidence, as universal screening for these organisms is not routine policy in many laboratories. The results presented suggest the need for increased clinical and laboratory awareness of this important pathogen.