Transduction of M+- and SOR+-markers in group A streptococci

Phagolysates obtained in passage of the virulent phage CA1 on M+ SOR+-cultures of streptococcus, serotype 22, offered a possibility of transduction of the M22+-sign to M-SOR--strains of serotype T12. Transductants were selected in direct bactericidal test with subsequent determination of their type in the indirect bactericidal test with homo- and heterologous immune sera. The UV-lysates of the lysogenic M+ SOR+-cultures of serotypes 4, 22, and 49 offered a possibility of transducing both signs conjointly. In this case transductants were selected by the SOR-phenotype in the dishes with serum agar. All the transductants retained the T-serotype of the recipient's strain and segregated M-- and SOR--clones with high frequency. There were for the first time obtained in streptococcus of group A proofs of transduction of M+- and SOR+-signs pointing to their determination by different, but closely conjoint genes. Conditions of the marker transduction, selection and study of transductant were chosen, they opened new possibilities for genetic analysis of the virulence of streptococcus, group A.