Effect of biofilm phenotype on resistance of Gardnerella vaginalis to hydrogen peroxide and lactic acid

Patterson, Jennifer L. BS
Girerd, Philippe H. MD
Karjane, Nicole W. MD
Jefferson, Kimberly K. PhD

From the Departments of Microbiology and Immunology (Ms Patterson, Dr Jefferson) and Obstetrics and Gynecology (Drs Girerd and Karjane), Virginia Commonwealth University, Richmond, VA.

Reprints: Kimberly K. Jefferson, PhD, Department of Microbiology & Immunology, Virginia Commonwealth University, PO Box 980678, Richmond, VA 23298; [email protected]

Supported by National Institutes of Health grant R21AI61590-02 from the National Institute of Allergy and Infectious Diseases.

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Received for publication October 23, 2006; accepted February 22, 2007

American Journal of Obstetrics and Gynecology 197(2):p 170e1-170e7, August 2007.

Objective

Bacterial vaginosis is the most common vaginal disorder worldwide. Certain lactobacilli produce H₂0₂ and lactic acid, which normally suppress growth of anaerobes; however, in bacterial vaginosis, Gardnerella vaginalis and other anaerobes proliferate, and the number of lactobacilli decreases. G vaginalis colonizes the vaginal epithelium as a biofilm, which likely plays a role in colonization and relapsing infection.

Study Design

We developed an in vitro model for G vaginalis biofilm formation and compared susceptibilities of biofilms vs planktonic cultures to H₂0₂ and lactic acid. The structure and composition of the biofilm matrix were studied in order to design a method for biofilm dissolution.

Results

Biofilms tolerated 5-fold and 4–8 fold higher concentrations of H₂0₂ and lactic acid (respectively) than planktonic cultures. Proteolytic dissolution of biofilms reduced sensitivity to H₂0₂ and lactic acid.

Conclusion

Increased tolerance to H₂0₂ and lactic acid suggests that biofilm formation contributes to the survival of G vaginalis in the presence of lactobacilli.