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A low molecular weight enterotoxic hemolysin from clinical Enterobacter cloacae
S Simi1, G V Carbonell, R M Falcón
1Departamento de Microbiologia e Immunologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas (INICAMP), SP, Brazil.
Canadian Journal of Microbiology
|October 22, 2003
Summary
A novel hemolysin produced by Enterobacter cloacae clinical isolates was identified. This toxin causes intestinal damage in rats, suggesting it is a potential virulence factor in E. cloacae infections.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Biochemistry
Background:
- Enterobacter cloacae is an opportunistic pathogen.
- Hemolytic activity is a potential virulence factor in bacterial infections.
Purpose of the Study:
- To identify and characterize a hemolysin produced by clinical isolates of Enterobacter cloacae.
- To investigate the role of this hemolysin in bacterial virulence.
Main Methods:
- Isolation and identification of hemolytic Enterobacter cloacae strains.
- Partial purification of hemolysin using ultrafiltration and acetone extraction.
- Characterization of hemolysin stability (heat, pH, solvents, trypsin).
- In vivo assessment using the rat intestinal loop assay.
Main Results:
- Seven of 50 clinical isolates exhibited hemolytic activity.
- Partially purified hemolysin was heat-stable, soluble in organic solvents, and trypsin-resistant.
- Hemolysin demonstrated instability at neutral to alkaline pH.
- The toxin induced hemorrhagic fluid accumulation and histological damage in rat intestines.
Conclusions:
- Enterobacter cloacae produces a heat-stable hemolysin.
- This hemolysin is a potential virulence factor contributing to E. cloacae pathogenicity.
- Further research is warranted to elucidate the precise mechanism of action and clinical significance.