Parameters affecting the adherence and tissue tropisms of Streptococcus pyogenes
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Abstract:
Virulent M protein-containing strains of Streptococcus pyogenes were found to adhere well to human pharyngeal cells in vitro. In contrast, an avirulent M - strain and an enteropathogenic Escherichia coli strain adhered feebly. When various rat tissues were exposed to mixtures of a virulent S. pyogenes strain and an enteropathogenic E. coli strain, the relative proportions of the two pathogenic strains recovered from mucosal surfaces differed among the sites studied. S. pyogenes cells were found to adhere in higher proportions than enteropathogenic E. coli cells to the mucosal surfaces of rat tongues, whereas on surfaces of the urinary bladder, their affinities were reversed. The data indicate that bacterial adherence is influenced by the specificity of both the bacterial and epithelial surfaces, and they suggest that adherence may influence the tissue tropisms of pathogens. Early stationary-phase cells of S. pyogenes attached better to epithelial cells than did bacteria in other growth phases. The adherence of S. pyogenes cells was impaired by pretreatment with trypsin, wheat germ lipase, Tween 80, Triton X-100, sodium lauryl sulfate, heat at 56 C, anti-group A antiserum, the presence of phospholipids, and preincubation of the epithelial cells with Streptococcus salivarius cell walls. Altering the pH or treatment with ethylenediaminetetraacetic acid had no effect on the ability of S. pyogenes cells to adhere.
Insights
Virulent Streptococcus pyogenes strains show strong adherence to human cells, unlike avirulent strains or E. coli. Bacterial adherence specificity influences pathogen tissue tropism, with varying affinities observed across different host tissues.
Area of Science:
- Microbiology
- Pathogenesis
- Bacterial Adherence
Background:
- Streptococcus pyogenes is a significant human pathogen.
- Bacterial adherence to host tissues is a critical step in pathogenesis.
- Understanding tissue tropism is key to controlling infectious diseases.
Purpose of the Study:
- To investigate the adherence properties of virulent Streptococcus pyogenes.
- To compare adherence of S. pyogenes with Escherichia coli to various host tissues.
- To identify factors influencing bacterial adherence and tissue tropism.
Main Methods:
- In vitro adherence assays using human pharyngeal cells.
- In vivo competition assays with S. pyogenes and E. coli on rat tissues.
- Assessment of adherence under varying bacterial growth phases and pre-treatments.
Main Results:
- Virulent S. pyogenes adhered well to human pharyngeal cells, while avirulent strains and E. coli showed poor adherence.
- Differential adherence of S. pyogenes and E. coli was observed across rat tissues, with reversed affinities on tongue and bladder.
- Early stationary-phase S. pyogenes cells exhibited optimal adherence.
- Adherence was inhibited by trypsin, lipase, detergents, heat, antibodies, phospholipids, and S. salivarius cell walls.
Conclusions:
- Bacterial adherence is determined by specific interactions between bacterial and epithelial surfaces.
- Adherence mechanisms play a crucial role in determining pathogen tissue tropism.
- Factors such as growth phase and surface components significantly impact S. pyogenes adherence.