The influence of nutritional and cultural factors on CAMP factor production by group B streptococci

Twelve group B streptococci were examined for their capacity to produce CAMP factor in liquid culture media in which the carbohydrate type and concentration and/or the buffering capacity of the media were altered. The effects of these variations of media content on CAMP factor production were determined and related to effects on growth yield and pH changes during growth. For 9 of the 12 strains tested higher CAMP factor titres were obtained in maltose broth than in glucose broth, and accompanying changes in pH were greater and more rapid in glucose containing media. It is suggested that the lesser pH changes occurring during growth in maltose broth may be the mechanism whereby higher CAMP titres were obtained with these strains. The influence of carbohydrate type was not observed with the remaining 3 strains tested, but maximum CAMP factor yields were obtained in the presence of maltose and non-inhibitory concentrations of buffer. CAMP factor production for all strains of GBS may be increased by the addition of maltose and buffer to standard media.