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BMC Infect Dis. 2010 May 19;10:120. doi: 10.1186/1471-2334-10-120.

Cervicovaginal fluid and semen block the microbicidal activity of hydrogen peroxide produced by vaginal lactobacilli.

Author information

1
Mucosal Protection Laboratory, Thomas C, Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA. eohanlon@jhu.edu

Abstract

BACKGROUND:

H2O2 produced by vaginal lactobacilli is believed to protect against infection, and H2O2-producing lactobacilli inactivate pathogens in vitro in protein-free salt solution. However, cervicovaginal fluid (CVF) and semen have significant H2O2-blocking activity.

METHODS:

We measured the H2O2 concentration of CVF and the H2O2-blocking activity of CVF and semen using fluorescence and in vitro bacterial-exposure experiments.

RESULTS:

The mean H2O2 measured in fully aerobic CVF was 23 +/- 5 microM; however, 50 microM H2O2 in salt solution showed no in vitro inactivation of HSV-2, Neisseria gonorrhoeae, Hemophilus ducreyii, or any of six BV-associated bacteria. CVF reduced 1 mM added H2O2 to an undetectable level, while semen reduced 10 mM added H2O2 to undetectable. Moreover, the addition of just 1% CVF supernatant abolished in vitro pathogen-inactivation by H2O2-producing lactobacilli.

CONCLUSIONS:

Given the H2O2-blocking activity of CVF and semen, it is implausible that H2O2-production by vaginal lactobacilli is a significant mechanism of protection in vivo.

PMID:
20482854
PMCID:
PMC2887447
DOI:
10.1186/1471-2334-10-120
[Indexed for MEDLINE]
Free PMC Article

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