emm Typing and Validation of Provisional M Types for Group A Streptococci
Author Information
Author(s): R. Facklam, B. Beall, A. Efstratiou, V. Fischetti, D. Johnson, E. Kaplan, P. Kriz, M. Lovgren, D. Martin, B. Schwartz, A. Totolian, D. Bessen, S. Hollingshead, F. Rubin, J. Scott, G. Tyrrell
Primary Institution: Centers for Disease Control and Prevention
Hypothesis
The study explores the development and use of the 5' emm variable region sequencing in relation to existing serologic typing systems for group A streptococci.
Conclusion
The emm typing system is a reliable epidemiologic tool for subdividing group A streptococci and can often classify isolates that are difficult to type by serologic methods.
Supporting Evidence
- Nearly 100% of the cultures could be genotyped by the emm typing system.
- Only one of more than 1,500 GAS isolates could not be emm typed by current methods.
- The discriminatory power of the genotypic emm sequence-typing scheme approximates that of the phenotypic M-serotyping scheme.
Takeaway
Scientists are figuring out how to better identify different types of bacteria that can make people sick, using a special method that looks at their genes.
Methodology
The study involved sequencing the 5' ends of emm genes from reference strains and clinical culture specimens to develop a molecular-based typing system.
Limitations
The study does not address the full extent of putative M-serotype/emm sequence-type discordancies.
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