Novel emm4 lineage associated with an upsurge in invasive group A streptococcal disease in the Netherlands, 2022

• DOI: 10.1099/mgen.0.001026
• Publication Date: 2023-06-01T14:17:59Z
• Authors: Boas C.L. van der...; Wendy C.M. Bril-K...; Lidewij W. Rumke; Stefan M.T. Vestjens; Linda A.M. Koster; Marloes Willemsen; Marlies A. van Ho...; Nynke Y. Rots; Bart J.M. Vlaminckx; Brechje de Gier; Nina M. van Sorge
• Keywords: public health surveillance: outbreak; 0301 basic medicine; Antigens, Bacterial; Epidemiology; Streptococcus pyogenes; 0206 medical engineering; Short Communications; COVID-19; 02 engineering and technology; Microbiology; 3. Good health; outbreak [public health surveillance]; 03 medical and health sciences; emm typing; whole-genome sequencing; Streptococcal Infections; Genetics; Humans; Carrier Proteins; Molecular Biology; Netherlands; Bacterial Outer Membrane Proteins

Invasive group A streptococcal (iGAS) disease cases increased in the first half of 2022 in the Netherlands, with a remarkably high proportion of emm4 isolates. Whole-genome sequence analysis of 66 emm4 isolates, 40 isolates from the pre-coronavirus disease 2019 (COVID-19) pandemic period 2009–2019 and 26 contemporary isolates from 2022, identified a novel

Streptococcus pyogenes

lineage (M4NL22), which accounted for 85 % of emm4 iGAS cases in 2022. Surprisingly, we detected few isolates of the emm4 hypervirulent clone, which has replaced nearly all other emm4 in the USA and the UK. M4NL22 displayed genetic differences compared to other emm4 strains, although these were of unclear biological significance. In publicly available data, we identified a single Norwegian isolate belonging to M4NL22, which was sampled after the isolates from this study, possibly suggesting export of M4NL22 to Norway. In conclusion, our study identified a novel S. pyogenes emm4 lineage underlying an increase of iGAS disease in early 2022 in the Netherlands and the results have been promptly communicated to public health officials.