Identification of streptococci: use of lysozyme and Streptomyces albus filtrate in the preparation of extracts for Lancefield grouping

A combination of lysozyme and Streptomyces albus filtrate has been shown effective in extracting group-specific antigen for all commonly occurring serologically groupable streptococci. A prospective comparison of this method with that of Rantz and Randall (1955) for grouping 761 clinical isolates has confirmed its accuracy, which in our hands exceeded that of the latter more complicated method of serogrouping. Its rapidity and simplicity and the relatively low cost of the reagents involved make it practical for routine use in clinical bacteriology laboratories.