Comparison of the agglutination and the co-agglutination techniques in T-tying of Streptococcus pyogenes

A comparison of two different methods in T-typing 200 Norwegian group A strains is reported. The traditional agglutination technique was compared with the co-agglutination method of Christensen and co-workers. Fifty-five strains could not be typed by either method. The typing results for 128 of the strains were in agreement. The most common T types were the folloiwng: 1, 4, 8, 12, 13, 28, and strains belonging to the T pattern 5/11/12/27/44.