Serial observations were obtained over an 18-month period of 270 Indian children with pyoderma. Beta-hemolytic streptococci, predominantly group A, and coagulasepositive staphylococci were recovered from the majority of lesions (80% and 70%, respectively), both on the initial and on subsequent cultures. The predominant agglutination patterns of streptococcal strains were similar to those described in other studies of superficial skin infections. Another agglutination pattern, 17/23/47, not previously observed to be prevalent in streptococci from skin lesions, was identified in a significant number of skin cultures. In addition, the hitherto undescribed association of M-types, including type 41 and a new M-type, with strains of T-agglutination pattern 3/13/B3264 was found. In striking contrast to the streptococcal strains, established "impetigo" strains of Staph. aureus (type 71 or other group II strains) were in the minority. Throat cultures of children with pyoderma suggested a limited relationship between infection or colonization of the pharynx and infection of the skin, while nasal streptococci were more closely correlated with and possibly derived from the flora of the skin lesions. Titers of ASO were not often elevated over control values in children with pyoderma, while anti-DNAse B titers were more commonly increased.
Group A streptococci isolated from skin lesions prior to or at the time acute nephritis was recognized included type 12 (M and T) and strains classified by T-agglutination as 5/27/44, 11 and 4. The role of infection or colonization of the upper respiratory tract in the relationship of pyoderma to nephritis was not clarified in these studies. Moreover, in view of the frequency of change of group A streptococcal strains in skin lesions, as shown in serial observations in this study, the nephritogenic significance of streptococci recovered from skin lesions at the time of recognition of nephritis must remain in some doubt. Questions concerning the pathogenesis of endemic nephritis associated with pyoderma can probably be most reliably answered by frequent, prospective observations of a normal population with significant occurrence of streptococcal skin infections.