Korean J Clin Microbiol.  2006 Apr;9(1):18-23.

Association of T Antigens with emm Genotypes of Group A Streptococci

• Jung HJ
• Koh EH
• Kim S
• Maeng KY
• Kang SH

Abstract

BACKGROUND: T typing has been used as a screening test for epidemiologic studies of group A streptococci (GAS) infections or carriers, and M typing has been performed for virulence studies. However, M typing is difficult to perform in routine laboratories. Recently, genotyping of the emm gene, which encodes the M protein, has become available. We investigated which T antigen is closely associated with a certain emmgenotype.
METHODS
GAS were collected from the children in Jinju who were asymptomatic carriers (N=349) or had acute pharyngitis (N=122) during the 3 year-period from 2002 through 2004. T typing was performed by a slide aggulutination, and emmgenotyping by PCR and DNA sequencing.
RESULTS
More than 90% of T1, T3, T6, T12, T25, and T5/27/44 antigens were associated with emm1, emm3, emm6, emm12 and 22, emm75, and emm44/61 genotypes, respectively; however, other T antigens, such as T2, T4, T7, T11, and B3264, were not associated with any particular emm genotypes.
CONCLUSION
Several T antigens are so closely associated with particular emm genotypes that one could predict emmgenotypes based on the result of T typing.

Keyword

Group A streptococci; Streptococcus pyogenes; T antigen; emm genotype; Epidemiology; Pharyngitis

MeSH Terms

Antigens, Viral, Tumor*
Child
Epidemiology
Genotype*
Gyeongsangnam-do
Humans
Mass Screening
Pharyngitis
Polymerase Chain Reaction
Sequence Analysis, DNA
Streptococcus pyogenes
Virulence
Antigens, Viral, Tumor