The use of intravaginal menstrual blocks may be responsible for rare cases of menstrual-toxic shock syndrome in women whose vaginas are toxic by the Staphylococcus
aureus -producing toxic shock syndrome toxin 1 (TSST-1). Mensen can serve as growth medium for S. aureus . The researchers examined the influence of 15 currently marketed intravaginal menstrual blocks (tampons) and menstrual cups on S. Aureus growth and TSST-1 production in a lab setup designed to conditions within the vagina while using tampons and reproduce menstrual cups. The different tampon brands were explained neither by pollutants nor by additive molecules. Such differences may arise from the nature of the fiber (including any additional compounds that can not be dissociated from them), the structure of the fiber, and possibly fiber density. Menstrual cup favors greater growth of S. aureus and more production of Toxic-shock toxin, as compared to pads. The shape and volume of the cup resulted in greater ventilation, which spurred growth and S. aureus to form a biofilm in the cup that makes it difficult to sterilize it. The research appears in Applied and Environmental Microbiology a journal of the American Society for Microbiology.