PCR amplification of streptococcal DNA using crude cell lysates.

Gram-positive organisms such as streptococci and enterococci are often difficult to lyse. Obtaining DNA for procedures such as PCR amplification usually requires a large scale isolation for each strain under investigation. We describe a simple procedure for small volumes of whole cells, involving pretreatment with detergent and proteinase that allows for efficient release of DNA for PCR amplification. This procedure is fast, reproducible, can be used with a large number of samples, and has been successfully applied to a variety of streptococcal and enterococcal strains.