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Teichoic acids of group D streptococci with special reference to strains from pig meningitis (Streptococcus suis)
S D Elliott1, M McCarty, R C Lancefield
1Rockefeller University, New York.
Abstract:
Immunoelectrophoresis revealed in phenol extracts from S. faecalis and S. faecium a mixture of free and lipid-bound teichoic acids, both reactive with Group D antisera. In phenol extracts from S. suis only lipid-bound teichoic acid, also reactive with Group D antiserum, was seen. This difference probably accounts for the low yield of Group D antigen from S. suis as compared with S. faecalis and S. faecium when heating at pH 2 is used for extraction. When phenol is used good yields are obtained from S. suis as well as from S. faecalis and S. faecium. Lipoteichoic acids from S. faecalis and S. faecium have a backbone structure the same as or similar to that of Group A streptococcal teichoic acid. Lipoteichoic acid from S. suis has a structure differing from that of S. faecalis and S. faecium, e.g., possibly in the attachment of its glucosyl substituents. Precipitation reactions between S. suis lipoteichoic acid and Group D antisera were specifically inhibited by glucose. Reactions between S. bovis phenol extracts and some Group D antisera were also specifically inhibited by glucose, but extracts from S. faecalis and S. faecium were not. This may indicate a monosaccharide glucosyl substituent in teichoic acid from S. suis and S. bovis instead of the di- or trisaccharide previously postulated as the glucosyl substituent in the teichoic acid of S. faecalis.
Insights
This study reveals distinct teichoic acid structures in Streptococcus species. Streptococcus suis and Streptococcus bovis possess unique lipoteichoic acid structures, differing from Streptococcus faecalis and Streptococcus faecium.
Area of Science:
- Microbiology
- Immunochemistry
- Biochemistry
Background:
- Teichoic acids are crucial cell wall components in Gram-positive bacteria.
- Group D antigen identification is important for bacterial classification and diagnostics.
Purpose of the Study:
- To investigate and compare the structures of teichoic acids in different Streptococcus species.
- To understand the implications of structural differences on antigenicity and extraction yields.
Main Methods:
- Phenol extraction of bacterial cell walls.
- Immunoelectrophoresis to analyze teichoic acid components.
- Precipitation inhibition assays using glucose to characterize glycosyl substituents.
Main Results:
- Streptococcus faecalis and Streptococcus faecium contain both free and lipid-bound teichoic acids reactive with Group D antisera.
- Streptococcus suis contains only lipid-bound teichoic acid reactive with Group D antiserum.
- Lipoteichoic acid from S. suis exhibits a different structure, potentially with monosaccharide glucosyl substituents, compared to S. faecalis and S. faecium.
Conclusions:
- Structural variations in lipoteichoic acids among Streptococcus species influence antigenicity and extraction efficiency.
- S. suis and S. bovis may possess monosaccharide glucosyl substituents in their teichoic acids, unlike S. faecalis and S. faecium.