Colistin-oxolinic acid-blood agar: a new selective medium for streptococci.

The development and evaluation of a new selective medium (colistin-oxolinic acid-blood agar) for streptococci is described. Streptococci of medical and veterinary importance grew well on the medium. Gram-negative organisms, staphylococci. Bacillus spp., and coryneforms are all inhibited. It was concluded that the medium is valuable for the isolation of streptococci in pure culture from mixed flora and has advantages over other media previously described. Increased isolation rates were obtained together with earlier identification of the isolated strains.