Key areas of newest diphtheria research

1.  Genomic surveillance and outbreak response Europe-Wide Outbreaks and Genomic Tracking: The largest diphtheria outbreak in Western Europe in 70 years occurred among migrants entering Europe in 2022, with sustained transmission into 2023 and 2025. Whole-genome sequencing and multi-locus sequence typing (MLST) revealed multiple genetic clusters circulating across borders, highlighting the importance of rapid genomic data sharing for outbreak management. Cross-Border Collaboration: Enhanced international cooperation and data sharing among European countries have been critical for detecting and responding to diphtheria outbreaks, especially among vulnerable populations such as migrants, homeless individuals, and people who inject drugs. 2.  Antimicrobial resistance and treatment Antibiotic susceptibility patterns: Most isolates from recent European outbreaks were susceptible to penicillin and amoxicillin, but resistance to erythromycin and other macrolides was observed in some strains. Notably, some isolates carried genes for resistance to both macrolides and beta-lactams (e.g., ermX, blaOXA-2), although concurrent resistance to both classes was rare. Treatment Outcomes: Early administration of diphtheria antitoxin...