title: Modified Christie-Atkins-Munch-Petersen (CAMP) test for direct identification of hemolytic and nonhemolytic group B streptococci on primary plating.
abstract: A primary plating medium, using sheep blood agar with preformed zones of cell-free staphylococcal beta-hemolysin, was used for direct identification of both hemolytic and nonhemolytic group B streptococci by the direct elicitation of the Christie-Atkins-Munch-Petersen (CAMP) reaction. A positive CAMP reaction consisted of a semilunar-shaped area or circle of complete hemolysis of sheep erythrocytes and occurred only when colonies of group B streptococci developed along the periphery of the preformed zone of staphylococcal beta-hemolysin. Of 104 simulated specimens containing group B streptococci in combination with a variety of microbial species and of 85 vaginal specimens examined, direct recognition of group B streptococci was possible in 64 (61.5%) simulated specimens and in 12 (100%) vaginal cultures. Group B streptococcal colonies not developing along the active edge of staphylococcal beta-hemolysin were still identified by subculture. Of particular value was the facilitated recognition of colonies of nonhemolytic group B streptococcal strains and of hemolytic group B streptococci few in number or overgrown by other microbial species.
mesh_terms: D001431:Bacteriological Techniques; D003470:Culture Media; D005260:Female; D006460:Hemolysin Proteins; D006461:Hemolysis; D006801:Humans; D013292:Streptococcus agalactiae / Q000145:classification* / Q000502:physiology; D014621:Vagina / Q000382:microbiology
chemical_list: D003470:Culture Media; D006460:Hemolysin Proteins