Susceptibility of group A streptococci to oleic acid and ultraviolet light. Comparison of strains from throat and skin.

Group A streptococcal strains of some serotypes can be cultured repeatedly from normal human skin for days or weeks and subsequently produce pyoderma, but strains of other serotypes that cause pharyngitis are rarely recovered from normal human skin or skin lesions. In an attempt to understand the biological differences between "skin" and "throat" strains of group A streptococci, we studied their susceptibility to two bactericidal agents operative at the skin surface--oleic acid and UV light. No consistent differences were found between skin and throat strains; all streptococcal strains were exquisitely sensitive to both oleic acid (10 microgram/ml) and UV light (60 microW/cm2).