Effect of vaginal contraceptive sponges on growth of toxic shock syndrome-associated Staphylococcus aureus in vitro.

Toxic Shock Syndrome (TSS) is associated with certain toxin-producing strains of Staphylococcus aureus (TSS-S aureus), and with the use of some vaginal devices such as tampons or contraceptive diaphragms. The present study was designed to examine the effect of Nonoxynol-9 (N-9), and of a newly-approved vaginal contraceptive sponge (VCS) containing N-9 on the growth of TSS-S aureus in vitro. Flasks containing culture media inoculated with TSS-S aureus were incubated at 37 degrees C for 30 hours, in the presence or absence of either a VCS, or N-9 alone. At 0.5, 1, 2, 6, and 12 hours, there was suppression of TSS-S aureus colony counts in media containing VCS, compared to control. Colony counts from media containing N-9 demonstrated suppression at 0.5, 1, 2, and 6 hours. After incubation as long as 30 hours, colony counts from VCS-containing media approached, but did not exceed, counts from control media. From these data, it is concluded that this VCS containing N-9 does not enhance the growth of TSS-S aureus in vitro. Instead, an inhibition of bacterial growth for at least 12 hours is observed in media containing VCS, consistent with a bacteriostatic effect. If such an effect is also present in vivo, it would suggest that this type of VCS is unlikely to increase the risk of TSS.