[Comparison of different methods for the identification of groups of streptococci]

The Streptococci, isolated from 500 mucus-pharyngeal tampons, have been tested, for a group identification, by means of four different techniques in order to value the specificity and reliability in comparison with more traditional and, sometimes, more complex tests; such as Maxted and Lancefield. The most suitable method for routine researchers of microbiology laboratories is the one based on the extraction, by means of enzyme obtained from Streptomyces Griseus, of streptococci antigens before starting their serum identification, possible for A-B-C-D-F-G groups (Streptex). On the contrary, the method based on the links of group-specific antibodies with the A protein of the surface of Staphylococci Cowan I, has resulted more defective because Streptococci D and F cannot be grouped, and less specific because of frequent co-agglutinations.