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Distribution of fibronectin-binding proteins among group A streptococci of different M types
S Natanson1, S Sela, A E Moses
1Department of Clinical Microbiology and Infectious Diseases, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Abstract:
Binding of fibronectin by group A streptococci (GAS) promotes adherence to epithelial cells. The fibronectin-binding activity and the presence of prtF, a gene encoding a fibronectin-binding protein, were studied among 109 strains. Fifty-six strains of 42 different M types possessed prtF-related genes, and 89% of these strains bound fibronectin at high levels. The prtF-related genes varied in the number of repeats that constitute one of its two fibronectin-binding domains. Fifty-three strains of 21 different M types lacked prtF. Thirty-nine of these (74%), representing 13 different M types, bound fibronectin at very low levels. However, 9 (17%), of 5 different M types, bound fibronectin at high levels. The presence of prtF and the capacity to bind fibronectin correlated strongly with the M type of various strains of GAS. This correlation may suggest the existence of a relationship between fibronectin binding and the pathogenic potential of GAS.
Insights
Group A Streptococcus (GAS) strains with the prtF gene strongly bind fibronectin, aiding adherence. This fibronectin binding capacity correlates with M type, suggesting a link to GAS pathogenicity.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Group A Streptococcus (GAS) utilizes fibronectin binding for adherence to host epithelial cells.
- The fibronectin-binding protein, encoded by the prtF gene, is a key factor in this interaction.
Purpose of the Study:
- To investigate the prevalence of fibronectin-binding activity and the prtF gene in GAS strains.
- To determine the correlation between prtF presence, fibronectin binding levels, and M types of GAS.
Main Methods:
- Screening of 109 GAS strains for the presence of prtF-related genes.
- Quantification of fibronectin-binding activity in GAS strains.
- Correlation analysis between gene presence, binding levels, and M types.
Main Results:
- Fifty-six strains (42 M types) possessed prtF-related genes; 89% showed high fibronectin binding.
- Fifty-three strains lacked prtF; 74% had low binding, but 17% exhibited high binding.
- A strong correlation was observed between prtF presence, fibronectin binding capacity, and GAS M type.
Conclusions:
- The presence of the prtF gene is a significant determinant of high fibronectin binding in GAS.
- Fibronectin binding in GAS is strongly associated with specific M types.
- This association suggests a potential link between fibronectin binding and the pathogenic potential of GAS.