[M protein gene (emm) typing of Streptococcus pyogenes]

T-agglutination typing and M protein gene (emm) typing were determined on the isolates of Streptococcus pyogenes taken from patients in Osaka and neighboring districts during 1996-2000. A total of 701 isolates were classified to 15 kinds of T types and type untypable. In all isolates, T 12 was revealed as the most dominant serotype, followed by T1, T4 and T2. The isolation rates of T 12 strains were high through these five years, and these of T1 or T4 strains formed epidemic waves showing the peak to be from 1997 to 1999 and 1998 to 2000, respectively. These of T2 strains were high in 1996 and 1997 and decreased rapidly. In 2000 T2 strain has not been detected. A total of 304 isolates were examined for emm typing. We are able to determine the emm type of all isolates including T-untypable (UT) isolates and to classify 21 kinds of emm types. T1, T2, T4, T6, T9, T11, T12, T22, T25 strains exhibited one T-type and emm type pattern association respectively such as T1/emm1, T2/emm2, T4/emm4, T6/emm6, T9/emm9, T11/emm11, T12/emm12, T22/emm22, T25/emm75. Whereas T13 strains had varied T/emm pattern associations such as T13/emm73, T13/emm77, T13/emm101. Similarly, T28, TB3264, UT had varied T/emm pattern associations. emm28 and emm87 were seen in T28, emm89 and emm94 in TB3264, emm2, emm12, emm22, emm58, emm75, emm77 and emm112 in UT. The emm typing method did not require many kinds of M typing antisera, and were successful by using the two highly conserved primers to amplify the emm gene and direct sequencing. Therefore, this method was a useful tool for typing Streptococcus pyogenes isolates.