In vitro evaluation of microbial adhesion to a contraceptive vaginal ring with a new polymer composition

Objective: The aim of the study was to evaluate in vitro the amount of Candida albicans and Lactobacillus acidophilus adhering to the surface of Ornibel, a contraceptive vaginal ring with a new polymer composition, in comparison with NuvaRing. Methods: Ornibel and NuvaRing were tested for adhesion of microorganisms in vitro. The vaginal rings were aseptically sectioned into 1 cm segments. Suspensions of C. albicans (1-2 × 10⁷ colony-forming units [CFU]/ml) and L. acidophilus (1-2 × 10⁸ CFU/ml) were prepared and incubated either in monoculture or as co-culture with the ring segments. After incubation, adherent C. albicans and L. acidophilus were quantified by plate counting. Results: In monoculture, the measured amount of adhesion of C. albicans on the ring surface was significantly lower with Ornibel compared with NuvaRing (p = 6.77 × 10^-5), while the adherence of L. acidophilus did not differ between the two rings. Similarly, when co-incubated with C. albicans, the number of adhering L. acidophilus microorganisms was significantly lower with Ornibel compared with NuvaRing (p = .018) . This reduction also resulted in significantly lower levels of adhering L. acidophilus in co-culture compared with L. acidophilus when incubated alone (p = .003). Conclusion: The study demonstrates that the adherence of C. albicans, as well as that of L. acidophilus when co-cultured with C. albicans, is lower with the Ornibel vaginal ring compared with NuvaRing. These in vitro findings warrant future human trials using molecular techniques to assess the vaginal microbiota composition and to establish whether Ornibel can support vaginal health.