The European Centre for Disease Control and Prevention (ECDC) has warned of an increase in the number of diphtheria cases among migrants in the European Union, and with «unusually widespread» resistance of ‘Corynebacterium diphtheriae’ to common oral and parenteral antibiotics.
Diphtheria is an infectious bacterial disease that can be prevented by vaccination. Transmission occurs through airborne respiratory droplets, direct contact with respiratory secretions or direct contact with exudate from infected skin lesions. Diphtheria may present with respiratory or skin symptoms and, in some cases, may affect the heart, kidneys and nervous system.
Since the beginning of 2022, as of December 2, 154 cases of diphtheria have been reported in eight European countries: Spain (1), Germany (64), Austria (42), Belgium (18), France (14), Norway (7), the Netherlands (5) and Italy (3).
Migrant-associated diphtheria cases have also been reported in Switzerland (25) and the United Kingdom (53), bringing the total number in Europe to 232 cases. Most cases have been diagnosed among migrants residing in or exposed to migrant shelters.
This is an increase of 140 cases since the publication of the ECDC report last October 6, when seven European countries reported 92 cases of diphtheria among migrants and one fatal case was identified. ‘C. diphtheriae’ has been detected in all cases, and most of them have presented with the cutaneous form of the disease.
On November 3, a rapid communication published in ‘Eurosurveillance’ reported two detections of ‘C. diphtheriae’ in Switzerland possibly related to the observed increase in the EU/EEA, and an unusually large expected resistance to common oral and parenteral antibiotics.
According to the authors, these findings questioned treatment options for bacterial co-infections in case wounds. On November 17, another rapid communication was published in ‘Eurosurveillance’, in which phenotypic and predicted resistance data from the German cases confirmed the observations of the predicted resistance profile of the two Swiss isolates.
On December 1, the UK Health Safety Agency (UKHSA) published ‘Supplementary Guidance for Cases and Outbreaks in Asylum Seeker Accommodation Settings’, recommending antimicrobial susceptibility testing of all ‘C. diphtheriae’ isolates.
In this regard, the ECDC has pointed out that «the occurrence of isolates (in other European countries) showing a genomic profile suggestive of antimicrobial resistance similar to that observed in Switzerland and Germany cannot be ruled out.»
In view of this situation, the ECDC has recommended, as a precautionary measure, that antimicrobial susceptibility testing be performed on all ‘C. diphtheriae’ isolates.
As of December 2, ECDC has clarified, in any case, that it has no data indicating increased transmission and outbreaks of ‘C. diphtheriae’ in the general EU/EEA population as a result of the increased number of diphtheria cases observed.
