In vivo assessment of human vaginal oxygen and carbon dioxide levels during and post menses

Abstract

Previous in vitro and in vivo animal studies showed that O(2) and CO(2) concentrations can affect virulence of pathogenic bacteria such as Staphylococcus aureus. The objective of this work was to measure O(2) and CO(2) levels in the vaginal environment during tampon wear using newly available sensor technology. Measurements by two vaginal sensors showed a decrease in vaginal O(2) levels after tampon insertion. These decreases were independent of the type of tampons used and the time of measurement (mid-cycle or during menstruation). These results are not in agreement with a previous study that concluded that oxygenation of the vaginal environment during tampon use occurred via delivery of a bolus of O(2) during the insertion process. Our measurements of gas levels in menses showed the presence of both O(2) and CO(2) in menses. The tampons inserted into the vagina contained O(2) and CO(2) levels consistent with atmospheric conditions. Over time during tampon use, levels of O(2) in the tampon decreased and levels of CO(2) increased. Tampon absorbent capacity, menses loading, and wear time influenced the kinetics of these changes. Colonization with S. aureus had no effect on the gas profiles during menstruation. Taken collectively, these findings have important implications on the current understanding of gaseous changes in the vaginal environment during menstruation and the potential role(s) they may play in affecting bacterial virulence factor production.

Staphylococcal and Streptococcal Superantigen Exotoxins

“…As noted previously, blood components, and more specifically hemoglobin peptides, negatively affect production of TSST-1 (147). The introduction of oxygen into the human vagina, a typically anaerobic environment, by tampons is now considered the major reason for the tampon association with mTSS (84,168,169). The introduction of oxygen would also explain the major association of mTSS with higher-absorbency tampons in that those tampons introduce more oxygen.…”

Inhibition of Staphylococcus aureus by Lysostaphin-Expressing Lactobacillus plantarum WCFS1 in a Modified Genital Tract Secretion Medium

“…During menstruation, the vaginal pH becomes neutral, most likely due to the influx of menses blood, which has a pH range of 6.9 to 7.2 (6). In addition, menses blood in the vagina also results in an elevated protein concentration (6) and an increase in oxygen and carbon dioxide concentrations (27), which all contribute to the production of TSST-1 by S. aureus (43,78).…”

Staphylococcus aureus Exotoxins Are Present In Vivo in Tampons

“…Similarly, it is well established that the in vitro environmental conditions that favor TSST-1 production can be present vaginally in menstruating women (10,12,25,33). However, only a single study has shown that TSST-1 can be produced vaginally (22).…”

“…We also have demonstrated that sections of tampons that have a low hemoglobin density contain serum proteins at about 1% of the level of those found in blood (unpublished data). The other major factor thought to be necessary for TSST-1 production is the presence of an aerobic environment, and we have previously established that such an environment is present vaginally through the oxygen in menstrual blood as well as through the inherent oxygen in tampons (10).…”

“…In vitro studies demonstrate that O 2 and CO 2 , iron, pH, glucose, and temperature are factors that can alter the concentration of TSST-1 produced by S. aureus (10,12,25,33,36). Recent in vitro studies have shown that both ␣-and ␤-globin chains of human hemoglobin can inhibit the production of TSST-1 without impacting growth of the organism (26).…”