Media-dependent subculture of nutritionally variant streptococci.

A case of infective endocarditis due to a strain of Streptococcus that demonstrated unusual nutritional requirements is reported. This strain was recognized as a nutritional variant because it could not be subcultured on certain routine primary plating and subculture media. The media-dependent recovery of this nutritionally variant Streptococcus is stressed, since media used routinely in some laboratories would result in this organism's being missed. Variability of routine media in supporting the growth of this isolate is also demonstrated.