GENOMIC SEQUENCE INVESTIGATION STREPTOCOCCUS PYOGENES CLUSTERS IN ENGLAND (2010-2015)

Streptococcus pyogenes infections range from mild to severe, including skin and soft tissue, respiratory and disseminated infection, with the elderly, postpartum mothers and neonates being at highest risks of developing severe and/or invasive disease. Clusters of S. pyogenes infection may have serious outcomes for patients and important implications for patient management in transmission via care workers and fomites. In cases where epidemiological information suggests a link, conventional typing may not always differentiate isolates from others obtained from unrelated clusters. The genomic sequence of 136 S. pyogenes isolates associated with 21 clusters of invasive infection in nursing care homes, elderly care hospital wards or maternity wards submitted to the reference laboratory from 2010-2015 was analysed. Genomic sequence of the isolates within clusters and contemporaneous isolates from geographically distinct clusters of S. pyogenes infection were compared. In the majority of clusters genomic sequence analysis resulted in greater discrimination than emm sequence typing and MLST analysis. Genomic sequences from epidemiologically linked isolates from patients, staff and healthcare environmental settings were highly conserved, differing by as few as 0 to 1 SNP in some cases and mirrored geographical data. Furthermore a total of 10 outbreak-related isolates were excluded from other isolates within the respective epidemiological outbreak using genomic SNP analysis