Serological groups and types of hemolytic streptococci isolated in Puerto Rico.

SummaryA bacteriological study of 116 pairs of excised tonsils showed that 62.8% harbored β-hemolytic streptococci. In contrast 705 cultures of normal throats similarly studied showed an incidence of 17.4% of this organism. This difference is due mainly to a higher percentage of Group A streptococci (30.2%) found in excised tonsils as compared to 1.2% in normal throats.The proportion of streptococci cultured from excised tonsils belonging to groups other than A was twice as large (32.6%) as that obtained from normal throat cultures (16%). In typing 95 strains of hemolytic streptococci by the precipitin method described by Swift et al4 representatives of types 44, 41, 1, 14, 19, 4, 36 and 39 were found. Approximately half the strains were untypable with the serums tested. Types 44 and 41 were most commonly found.