Outbreaks of human infection caused by pyogenic streptococci of Lancefield groups C and G.

Within a collection of 749 strains of group C streptococci (Streptococcus equisimilis) and 2348 of group G, isolated over a period of 6 years, there were clusters from 63 probable outbreaks of infection. These occurred in burns and maternity units, hospital wards, outpatient clinics, army camps and religious communities. Overall, it was possible to identify T-protein antigens in 88% of the group C strains and in 82% of group G. Serotyping by the identification of T-protein antigens was a useful method for the subdivision of these strains.