Related Experiment Videos
Analysis of the variability of S-fimbriae expression in an Escherichia coli pathogen
Abstract:
The uropathogenic Escherichia coli wild-type strain 536 produces S-fimbriae, P-related fimbriae and type I fimbriae. Using immuno-colony dot and ELISA techniques, variants were detected showing an increased degree of S-fimbrial production. It was demonstrated by immunofluorescence microscopy that in normal (wild-type) and hyper-S-fimbriated E. coli populations non-fimbriated cells also exist, and that the percentage of S-fimbriated and non-fimbriated bacteria was roughly identical in either population. Hyper-S-fimbriated variants could be stably maintained. The transition from wild-type to hyper-S-fimbriation, which occurs spontaneously, is markedly higher than vice versa. Southern blot analysis of the S fimbrial adhesin (sfa) determinants of normal and hyper-fimbriated strains revealed no marked difference in the gene structure.
Insights
Uropathogenic Escherichia coli can spontaneously increase S-fimbrial production, creating hyper-S-fimbriated variants. These variants are stable, though the gene structure for S fimbrial adhesin determinants shows no significant differences.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infections.
- UPEC strains, like the wild-type strain 536, produce various fimbriae, including S-fimbriae, which are important for adhesion and infection.
- Understanding the regulation of fimbrial expression is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the spontaneous emergence and characteristics of UPEC variants with enhanced S-fimbrial production.
- To compare the stability and genetic basis of hyper-S-fimbriated UPEC strains with wild-type strains.
Main Methods:
- Immuno-colony dot and ELISA techniques were used to detect and quantify S-fimbrial production.
- Immunofluorescence microscopy was employed to visualize fimbriation levels in bacterial populations.
- Southern blot analysis was performed to examine the gene structure of S fimbrial adhesin (sfa) determinants.
Main Results:
- Variants with significantly increased S-fimbrial production (hyper-S-fimbriated) were identified in UPEC strain 536.
- Both wild-type and hyper-S-fimbriated populations contained non-fimbriated cells, with roughly equal percentages in either population.
- Hyper-S-fimbriated variants demonstrated stable maintenance, and the transition from wild-type to hyper-S-fimbriation occurred spontaneously at a higher rate than the reverse.
- Southern blot analysis revealed no significant differences in the gene structure of the S fimbrial adhesin determinants between normal and hyper-fimbriated strains.
Conclusions:
- Spontaneous hyper-S-fimbriation is a stable phenotype in UPEC strain 536.
- The genetic basis for increased S-fimbrial production in these variants is not explained by alterations in the sfa gene structure.
- Further research is needed to elucidate the regulatory mechanisms underlying this phenotypic variation in fimbrial expression.