Effect of exposure to hydrogen peroxide on the virulence of Escherichia coli.
OBJECTIVE
To eliminate pathogenic bacteria, the host presents conditions that are stressful for bacteria. Oxidative stress arises when the concentration of pro-oxidants like hydrogen peroxide (H2O2 ) and superoxide anion increases to a level over the basal defence capacity of the cell. In the present study, we studied the effect of oxidative stress on the production of certain virulence factors by Escherichia coli .


METHODS
E. coli was exposed to oxidative stress by growing in the presence of different concentrations of H2O2 . The effect of oxidative stress on the expression of surface hydrophobicity, adherence, haemolysin production, serum resistance and phagocytosis was studied.


RESULTS
Oxidative stress caused a significant decrease in the expression of all the virulence factors of E. coli .


CONCLUSIONS
Synthesis of virulence factors can be significantly altered by oxidative stress and such changes may affect the pathogenicity of E. coli.
Hegde
A
A
Department of Microbiology, Kasturba Medical College, Mangalore - 575 001, Karnataka, India.
Bhat
G K
GK
Mallya
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000096:biosynthesis; D006460:Hemolysin Proteins / Q000096:biosynthesis; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D057927:Hydrophobic and Hydrophilic Interactions; D010587:Phagocytosis / Q000187:drug effects; D014774:Virulence / Q000187:drug effects; D037521:Virulence Factors / Q000096:biosynthesis
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; D037521:Virulence Factors; D006861:Hydrogen Peroxide