Reduction in Staphylococcus aureus Growth and Exotoxin Production and in Vaginal Interleukin 8 Levels Due to Glycerol Monolaurate in Tampons

Background. Staphylococcal menstrual toxic shock syndrome depends on vaginal production of exotoxins. Glycerol monolaurate (GML) inhibits Staphylococcus aureus exotoxin production in vitro. The purpose of this study was to determine whether GML, as a tampon fiber finish, inhibits production of exotoxins and the cytokine interleukin 8 (IL-8) during normal tampon use. Methods. On day 2 of menstruation, when vaginal S. aureus counts are high in colonized women, study participants exchanged their own preferred tampons, after wearing them for 2-6 h, for study tampons with or without GML (assigned randomly and blindly), which they then wore for 4-6 h. The women's own tampons and the study tampons with or without GML were assayed for S. aureus, the exotoxins toxic shock syndrome toxin 1 and a-toxin, and IL-8. Results. A total of 225 women completed the study. S. aureus was present in the tampons of 41 women (18%). Lower numbers of S. aureus and the exotoxins were detected in study tampons with or without GML than in women's own tampons; lower amounts of the exotoxins were present in study tampons with GML than study tampons without GML. The IL-8 level was lower in tampons from women without vaginal S. aureus compared with women with S. aureus and was lower in study tampons with GML than in study tampons without GML. Conclusions. Tampons that contain GML reduce S. aureus exotoxin production. S. aureus increases vaginal IL-8 levels, and GML reduces production of this proinflammatory cytokine. These results suggest that GML added to tampons provides additional safety relative to menstrual toxic shock syndrome as well as benefits for vaginal health generally, thus supporting the addition of GML to tampons.