Abstract
Three new streptococcal M serotypes, types 59, 60, and 61; have been described. They were first isolated from patients with pyoderma and acute glomerulonephritis (AGN), seen during epidemiological studies in Alabama. A possible antigenic relationship between types 59 and 61 was suggested by their T-agglutination reactions; a more specific T antiserum prepared for type 59 was useful in separating these two types, as well as other strains known to share T antigens 11, 12, and 5/27/44. On the basis of precipitin tests, a common antigenic determinant among types 59, 61, and 49 was suggested. This is of interest in view of the relation between these types and AGN. Type 59 has been relatively more widespread in distribution than type 61, but neither have been related to epidemic AGN. Type 60, first identified as "T-4," thus being related to previously described M types which share this antigen, is of great interest in terms of the epidemiology of AGN. Most strains in our collection were recovered from patients with pyoderma and AGN or from their infected siblings. Recently, the type was found to be prevalent among patients with pyoderma and AGN seen in Trinidad. Data reported in relation to these new types further illustrate the dichotomy in M serotypes common to pyoderma and AGN on the one hand and those types found in collections of patients with pharyngitis on the other hand. The high rate of non-M-typable streptococci among pyoderma collections, encountered earlier, is best explained by lack of suitable reference antisera available for prevalent pyoderma serotypes.