Lactobacillus crispatus Capsules: Single-Use Safety Study in the Macaca nemestrina Model

Background: Lactobacillus crispatus is a part of the normal vaginal microflora of humans. Goal: The goal of this study was to assess whether a capsule containing an H₂O₂-producing strain of L crispatus (CTV-05) would alter the vaginal microflora and/or epithelial tissues when applied intravaginally in the pig-tailed macaque model. Study Design: Ten sexually mature female Macaca nemestrina were assessed at baseline for quantitative vaginal microbiology and vaginal pH and with colposcopy. One capsule containing 10⁸ colony forming units of desiccated L crispatus CTV-05 was inserted into the vaginal fornix of each animal. Vaginal assessments were repeated on days 1 and 2 after capsule insertion. The L crispatus CTV-05 strain was identified with use of a DNA fingerprinting method. Results: Before product use, four of 10 animals had detectable levels of H₂O₂-producing lactobacilli. L crispatus CTV-05 was detected in 1 of 10 animals on day 1 and in 3 of 10 animals on day 2 following insertion of the capsule. There were no tissue changes observed by colposcopy. Vaginal pH decreased in two animals colonized by CTV-05, from 7.0 at baseline to 4.5 ± 0.5 on days 1 and 2 after product use. Conclusions: A single intravaginal application of capsules containing 10⁸ L crispatus CTV-05 resulted in vaginal colonization in three of 10 animals 2 days after use. The absence of colposcopic changes in the vagina/cervical tissues indicates that L crispatus capsules are well tolerated.