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Possible role of sarA in dehydroepiandrosterone-mediated increase in Staphylococcus aureus resistance to vancomycin
Balbina J Plotkin1, Monika Konaklieva
1Department of Microbiology and Immunology, Midwestern University, Downers Grove, Ill 60515, USA. Bplotk@Midwestern.edu
Background:
Dehydroepiandrosterone (DHEA), a steroid present throughout life, can induce an increase in resistance to vancomycin in methicillin-sensitive and methicillin-resistant clinical isolates of Staphylococcus aureus.
Methods:
The in vitro effect of DHEA on vancomycin killing of S. aureus with mutations in sarA and/or agr was determined by standard microtiter protocols and time to kill determinations.
Results:
Of the isolates tested, the strain with a deletion in sarAderived from a DHEA- responsive parent was not protected from vancomycin killing by DHEA. However, DHEA significantly (p < 0.01) slowed the rate of vancomycin killing of sarA-.
Conclusion:
These data indicate that sarA may play a role in DHEA-mediated protection from vancomycin killing of S. aureus.
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