[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]
Volume 24, Number 7—July 2018 / Research
Geographically Diverse Clusters of Nontoxigenic Corynebacterium diphtheriae Infection, Germany, 2016–2017
Alexandra Dangel1 , Anja Berger1, Regina Konrad, Heribert Bischoff, and Andreas Sing
Author affiliations: Bavarian Health and Food Safety Authority, Oberschleissheim, Germany (A. Dangel, A. Berger, R. Konrad, H. Bischoff, A. Sing); German Consiliary Laboratory on Diphtheria, Oberschleissheim (A. Berger, R. Konrad, A. Sing)
From 2016 through the middle of 2017, the German Consiliary Laboratory on Diphtheria noted an increase in nontoxigenic Corynebacterium diphtheriae isolates submitted from cities in northern Germany. Many patients for whom epidemiologic data were available were homeless, alcohol or drug abusers, or both. After performing routine diagnostics and multilocus sequence typing (MLST), we analyzed isolates of sequence type (ST) 8 and previously submitted isolates by whole-genome sequencing. Results were analyzed for phylogenetic relationship by core genome MLST (cg-MLST) and whole-genome single-nucleotide polymorphism profiles. Next-generation sequencing–based cg-MLST revealed several outbreak clusters caused by ST8; the geographic focus was in the metropolitan areas of Hamburg and Berlin. To achieve enhanced analytical depth, we used additional cg-MLST target genes and genome-wide single-nucleotide polymorphisms. We identified patient characteristics and detected transmission events, providing evidence that nontoxigenic C. diphtheriae infection is a potential public health threat in industrialized countries.
Keywords: Diphtheria; Corynebacterium diphtheriae; Germany.