Three diphtheria cases, aged 20, 11 and 10 years, have been reported from KwaZulu-Natal Province since 30 March 2018, including two toxin-producing Corynebacterium diphtheriae confirmed cases and one probable case. Two (67%, 2/3) of the cases have demised. A cluster of respiratory diphtheria cases occurred in Kwazulu-Natal in 2015. Subsequently, two additional cases from the same region were reported in 2016. In 2017, a cluster of three cases occurred in the Western Cape (WC) and a single case in the Eastern Cape.
We urge clinicians throughout the country to have a high awareness of the suspected diphtheria case definition and to notify these cases, as well as submit specimens for laboratory testing. Any person who presents with an upper respiratory tract illness characterised by a sore throat, low-grade fever and an adherent (pseudo)membrane of the nose, pharynx, tonsils or larynx should be considered as a suspected case.
Also, we remind all NHLS and private laboratories nationally to continue to actively screen for C. diphtheriae by plating all throat/tonsillar swabs onto Hoyle’s (tellurite-containing) medium. C. diphtheriae reduces potassium tellurite to tellurium to produce grey-black coloured colonies. On blood agar, C. diphtheriae is easily overlooked as glistening, creamy white colonies resembling Staphylococcus aureus. Alternately, please submit throat swabs (preferably in Amies/modified Stuart’s transport medium with charcoal) or tissue (pseudomembrane) samples to your local National Health Laboratory Service (NHLS) or private laboratories or to the Centre for Respiratory Diseases and Meningitis (CRDM) at the National Institute for Communicable Diseases (NICD) for culture and polymerase chain reaction (PCR).
Hoyle’s plates with suspected C. diphtheriae colonies must please be submitted to the NICD for confirmation and/or detection of toxin by Elek and PCR.
Guidelines for diphtheria management and laboratory detection can be accessed at
https://www.nicd.ac.za/index.php/diphtheria/
Additionally, please contact CRDM to assist with identification of suspected organisms or supply of Hoyle’s plates or swabs (Laboratory 011 555 0315/17/18, Linda de Gouveia 011 555 0327, lindad@nicd.ac.za, or Nicole Wolter 011 555 0352, nicolew@nicd.ac.za). For clinical queries please contact the NICD Hotline (082 883 9920) or Dr Anne von Gottberg (011 555 0316 or annev@nicd.ac.za).
