Experimental infections with group A streptococci in humans.

Experimental inoculation of 7 strains of Group A streptococci failed to result in either colonization or infection of normal intact skin of human volunteers. All strains rapidly died on normal skin; suppression of the resident microflora did not affect survival and no difference in survival was seen between inoculation on lipid-rich and lipid-poor body areas. Inoculation on skin damaged by superficial scarification resulted in localized infections when 1 x 10(4) or more organisms were inoculated into the wound by rubbing and covered with an impermeable plastic film. Intradermal inoculation resulted in localized cellulitis, regional lymphadenopathy, and fever. All strains were equally effective in producing localized infections in scarified skin.