Report of cases of and taxonomic considerations for large-colony-forming Lancefield group C XXXX .

@entity1 @entity13705 @entity883 @entity30180 @entity29599 @entity2688 @entity281 @entity583 @entity11674 @entity2259 @entity22193 @entity884
Traditionally, group C streptococci include four species: @entity30180 , @entity11674 , @entity29599 , and @entity22193 , the first three of which are group C beta-hemolytic streptococci (GCBHS). However, many of the beta-hemolytic streptococci carrying Lancefield group C antigen isolated from clinical specimens are S. milleri. These organisms can be differentiated by colony size. We retrospectively collected data concerning large-colony-forming GCBHS @entity2259 that occurred during a period of 8 years at the Massachusetts General Hospital. A total of 222 cases of @entity883 were identified; data on the Lancefield grouping were available in 192 cases: 45 cases (23.6%) were group A, 96 cases (50%) were group B, 7 cases (3.6%) were group C (large colony forming), and 44 cases (22.9%) were group G. The medical records for cases of large-colony-forming GCBHS @entity2259 were reviewed. In one case, the isolate was thought to be a contaminant; the other six cases are reported (five males and one female; mean age, 55 years). All @entity1 had severe underlying conditions, and none had a history of exposure to animals. The clinical syndromes included two cases of @entity2688 and one case each of @entity884 , @entity583 complicated by @entity281 , and @entity13705 . The diagnoses for two @entity1 with @entity281 were delayed. Three of the six @entity1 had fatal outcomes, and other two, after prolonged hospitalization, were transferred to a long-term rehabilitation center. We concluded that the severe outcomes reflect delay in diagnosis and treatment as well as the severity of the underlying diseases. The taxonomy of GCBHS is discussed. More reports differentiating large- and small-colony-forming GCBHS are needed.
