Epidemiological changes in invasive Streptococcus pyogenes infection during the UK alert period: A molecular comparative analysis from a tertiary Spanish hospital in 2023

Objectives

To study the genomic epidemiology of Streptococcus pyogenes causing bloodstream infections (GAS-BSI) in a Spanish tertiary hospital during the United Kingdom invasive S. pyogenes outbreak alert.

Methods

Retrospective epidemiological analysis of GAS-BSI during the January–May 2017–2023 period. WGS was performed using Ion torrent GeneStudio™ S5 system for emm typing and identification of superantigen genes in S. pyogenes isolated during the 2022–2023 UK outbreak alert.

Results

During 2023, there were more cases of GAS-BSI compared to the same period of previous year with a non-significant increase in children. Fourteen isolates were sequenced. The emm1 (6/14, 42.9%) and emm12 (2/14, 14.3%) types predominated; 5 of 6 (75%) emm1 isolates were from the M1_UK clone. The most detected superantigen genes were speG (12/14, 85.7%), speC (10/14, 71.4%), speJ (7/14, 50%), and speA (5/15, 33.3%). speA and speJ were predominant in M1_UK clone.

Conclusions

Our genomic epidemiology in 2023 is similar to the reported data from the UK outbreak alert in the same period and different from previous national S. pyogenes surveillance reports.