Characterization of group A streptococci (Streptococcus pyogenes): correlation of M-protein and emm-gene type with T-protein agglutination pattern and serum opacity factor

Strain characterization of group A streptococci (GAS) has traditionally been based on serological identification of M protein. Additional tests to determine T-protein serotype and production of streptococcal serum opacity factor (SOF) provide important information both to aid in and to supplement M-protein serotyping. Advances in DNA-sequencing technology in the late twentieth century resulted in the development of a method for determining the M type of GAS from the sequence of the gene encoding M protein, the emm gene. Although emm-sequence typing has largely replaced M typing in many laboratories, information provided by T typing and SOF determination continues to provide valuable supplementary information for strain characterization. A comprehensive summary of the correlation of T pattern and SOF production with M type was last published in 1993, several years before emm typing became widely available. Since then, the ease of M-type identification afforded by emm typing has resulted in an increase in the number of confirmed M/emm types of more than 50 %. However, comprehensive information about T-protein serotype and the correlation of SOF production with these new M/emm types is not widely available. This report presents a comprehensive summary of this information, not only for newly described types, but also updated information for previously described types. This information was extracted from combined records from streptococcal reference laboratories at the University of Minnesota and at the Centers for Disease Control and Prevention in Atlanta. Data from more than 40 000 strains (representing uncomplicated GAS infections, systemic invasive infections and strains associated with non-suppurative sequelae, collected from the US and diverse locations worldwide) were analysed.

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Environmental regulation of virulence in group A streptococci: transcription of the gene encoding M protein is stimulated by carbon dioxide.

Journal of Bacteriology ◽

10.1128/jb.174.17.5693-5701.1992 ◽

1992 ◽

Vol 174 (17) ◽

pp. 5693-5701 ◽

Cited By ~ 121

Author(s):

M G Caparon ◽

R T Geist ◽

J Perez-Casal ◽

J R Scott

Keyword(s):

Carbon Dioxide ◽

Environmental Regulation ◽

M Protein ◽

Group A Streptococci ◽

Gene Encoding ◽

Group A

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Serum Opacity Factor (SOF) of Streptococcus pyogenes Evokes Antibodies That Opsonize Homologous and Heterologous SOF-Positive Serotypes of Group A Streptococci

Infection and Immunity ◽

10.1128/iai.71.9.5097-5103.2003 ◽

2003 ◽

Vol 71 (9) ◽

pp. 5097-5103 ◽

Cited By ~ 46

Author(s):

Harry S. Courtney ◽

David L. Hasty ◽

James B. Dale

Keyword(s):

Streptococcus Pyogenes ◽

Rabbit Antiserum ◽

M Protein ◽

Group A Streptococci ◽

Streptococcal Infections ◽

Vaccine Candidates ◽

Human Antibodies ◽

Serum Opacity Factor ◽

Group A

ABSTRACT Serum opacity factor (SOF) is a protein expressed by Streptococcus pyogenes that opacifies mammalian serum. SOF is also a virulence factor of S. pyogenes, but it has not been previously shown to elicit a protective immune response. Herein, we report that SOF evokes bactericidal antibodies against S. pyogenes in humans, rabbits, and mice. Rabbit antiserum against purified recombinant SOF2 opsonized SOF-positive M type 2, 4, and 28 S. pyogenes in human blood but had no effect on SOF-negative M type 5 S. pyogenes. Furthermore, affinity-purified human antibodies against SOF2 also opsonized SOF-positive streptococci. A combination of antisera against M2 and SOF2 proteins was dramatically more effective in killing streptococci than either antiserum alone, indicating that antibodies against SOF2 enhance the opsonic efficiency of M protein antibodies. Mice tolerated an intravenous injection of 100 μg of SOF without overt signs of toxicity, and immunization with SOF protected mice against challenge infections with M type 2 S. pyogenes. These data indicate that SOF evokes opsonic antibodies that may protect against infections by SOF-positive serotypes of group A streptococci and suggest that different serotypes of SOF have common epitopes that may be useful vaccine candidates to protect against group A streptococcal infections.

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Identification and Characterization of a Novel Heme-Associated Cell Surface Protein Made by Streptococcus pyogenes

Infection and Immunity ◽

10.1128/iai.70.8.4494-4500.2002 ◽

2002 ◽

Vol 70 (8) ◽

pp. 4494-4500 ◽

Cited By ~ 79

Author(s):

Benfang Lei ◽

Laura M. Smoot ◽

Heather M. Menning ◽

Jovanka M. Voyich ◽

Subbarao V. Kala ◽

...

Keyword(s):

Recombinant Protein ◽

Cell Surface ◽

Surface Protein ◽

Cell Surface Protein ◽

Gene Encoding ◽

Invasive Infections ◽

Group A

ABSTRACT Analysis of the genome sequence of a serotype M1 group A Streptococcus (GAS) strain identified a gene encoding a previously undescribed putative cell surface protein. The gene was cloned from a serotype M1 strain, and the recombinant protein was overexpressed in Escherichia coli and purified to homogeneity. The purified protein was associated with heme in a 1:1 stoichiometry. This streptococcal heme-associated protein, designated Shp, was produced in vitro by GAS, located on the bacterial cell surface, and accessible to specific antibody raised against the purified recombinant protein. Mice inoculated subcutaneously with GAS and humans with invasive infections and pharyngitis caused by GAS seroconverted to Shp, indicating that Shp was produced in vivo. The blood of mice actively immunized with Shp had significantly higher bactericidal activity than the blood of unimmunized mice. The shp gene was cotranscribed with eight contiguous genes, including homologues of an ABC transporter involved in iron uptake in gram-negative bacteria. Our results indicate that Shp is a novel cell surface heme-associated protein.

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