Design: Prospective, observational pilot study

Setting: Single-site academic tertiary care medical center

Patients or Participants: Pre-menopausal women (age ≥18) undergoing laparoscopic (conventional or robotic) hysterectomy for benign conditions between February 2021 – June 2022 had cervicovaginal lavages and vaginal swabs collected preoperatively in the operating room and then 4 – 6 weeks postoperatively in clinic. Longitudinal patient-matched samples were utilized for analyses.

Interventions: Surgeon preference 4% chlorhexidine gluconate vs 7.5% povidone-iodine

Measurements and Main Results: 41 patients were enrolled in the study. A total of 21 had pre- and post-op samples collected and were included for vaginal microbiome analysis. In the PI (n = 8) arm, microbiome richness significantly (p=0.04) decreased post-surgery compared to pre-surgery. No difference in microbiome richness was observed in the CHX (n = 13) group. CHX treatment resulted in significant (p<0.001) changes in bacterial profiles on the Bray Curtis ordination. For microbiome composition, prior to surgery, most women in both arms (75-77%) exhibited Lactobacillus dominance. PI did not change the overall profiles, whereas CHX impacted Lactobacillus iners-dominant profiles, which shifted to other lactobacilli (3/6) or bacterial vaginosis-associated bacteria (2/6). However, Lactobacillus crispatus-dominant profiles, which are optimal to vaginal health, were not impacted by either treatment. Vaginal pH did not significantly change after either treatment. Cervicovaginal immunoproteomic analysis and in-vitro testing of species-specific effects of CHX on vaginal lactobacilli growth are ongoing and findings will be reported at the time of the conference.

Conclusion: This pilot study suggests that there is no significantly increased postoperative dysbiosis with the use of CHX compared to PI as a vaginal preparation. Longitudinal studies with larger and diverse cohorts are needed to validate our findings.