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Whole-cell and periplasmic protein banding patterns of environmental and human Bacteroides fragilis strains
R M Domingues1, K E Avelar, W G Souza
1Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Brasil.
Abstract:
In order to investigate the relationship among virulent and avirulent Bacteroides fragilis strains, SDS-PAGE of whole-cell proteins (WP) and periplasmic proteins (PP) were used to establish a protein profile of strains isolated from human infections, fecal flora and environmental water. Despite different sources of the strains, no significant differences were observed as determined by the WP SDS-PAGE analysis. In contrast, the proteins obtained from the bacterial periplasm showed differences in the electrophoretic protein profile. Two distinct PP profile patterns were obtained. Pattern A included 6 out of the 8 virulent strains and pattern B, 6 out of 8 avirulent strains. Interestingly, an environmental strain that was capable of inducing abscesses in mice, had a PP profile highly similar to that of the virulent strains from human infections. These data indicate that PP from B. fragilis may be useful to characterize differences among virulent and avirulent strains. Moreover, strains isolated from environmental water may also be a source of exogenous infections by B. fragilis.
Insights
Periplasmic protein profiles effectively differentiate virulent and avirulent Bacteroides fragilis strains. Environmental Bacteroides fragilis strains may pose infection risks, highlighting the importance of water quality monitoring.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Protein Analysis
Background:
- Bacteroides fragilis is an opportunistic pathogen implicated in various human infections.
- Distinguishing virulent from avirulent strains is crucial for understanding pathogenesis and infection control.
- Previous studies have explored protein profiles for bacterial characterization.
Purpose of the Study:
- To investigate the potential of protein profiles in differentiating virulent and avirulent Bacteroides fragilis strains.
- To compare protein profiles of strains from diverse sources, including human infections, fecal flora, and environmental water.
Main Methods:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was employed to analyze whole-cell proteins (WP) and periplasmic proteins (PP).
- Protein profiles were established for Bacteroides fragilis strains isolated from human infections, fecal flora, and environmental water.
- Comparative analysis of electrophoretic patterns was performed.
Main Results:
- Whole-cell protein (WP) SDS-PAGE analysis revealed no significant differences among strains from various sources.
- Periplasmic protein (PP) SDS-PAGE analysis identified two distinct electrophoretic profile patterns.
- Pattern A was predominantly associated with virulent strains, while Pattern B was linked to avirulent strains; an environmental strain showed a profile similar to virulent human isolates.
Conclusions:
- Periplasmic protein profiles serve as a valuable tool for differentiating virulent and avirulent Bacteroides fragilis strains.
- Environmental Bacteroides fragilis isolates, including those from water, can be pathogenic and represent a potential source of exogenous infections.
- Further research into environmental reservoirs of Bacteroides fragilis is warranted for public health.