Impact of vaginal douching products on vaginal Lactobacillus, Escherichia coli and epithelial immune responses

Helai Hesham,Alissa J. Mitchell,Agnes Bergerat,Kristin Hung,Caroline M. Mitchell

doi:10.1038/s41598-021-02426-5

Abstract

We compared the effect of commercial vaginal douching products on Lactobacillus crispatus, L. jensenii, L. gasseri, L. iners, E. coli, and immortalized vaginal epithelial cells (VK2). All studied douching products (vinegar, iodine and baking soda based) induced epithelial cell death, and all inhibited growth of E. coli. Co-culture of vaginal epithelial cells with any of the lactobacilli immediately following exposure to douching products resulted in a trend to less human cell death. However, co-culture of epithelial cells with L. iners was associated with higher production of IL6 and IL8, and lower IL1RA regardless of presence or type of douching solution. Co-culture with L. crispatus or L. jensenii decreased IL6 production in the absence of douches, but increased IL6 production after exposure to vinegar. Douching products may be associated with epithelial disruption and inflammation, and may reduce the anti-inflammatory effects of beneficial lactobacilli.

Highlights

Between 10 and 40% of American women use vaginal douching products to treat vaginal discharge, odor or discomfort[1,2,3,4]
There are no in vitro studies looking at the inhibitory effects of douching products on the most common vaginal Lactobacillus species (L. crispatus and L. iners), or E. coli, the most common pathogen isolated in Urinary tract infections (UTI)
We examined the effect of douching products on the vaginal epithelium by co-culturing immortalized vaginal epithelial cells (VK2) with douching solution diluted 1:4 in the cell culture media (keratinocyte serum-free (KSF) medium) for one hour

Summary

Introduction

Between 10 and 40% of American women use vaginal douching products to treat vaginal discharge, odor or discomfort[1,2,3,4]. Women with recurrent vaginal infections are advised not to douche, studies of vaginal washing cessation have not demonstrated dramatic restoration of a Lactobacillus-dominant vaginal microbiota in women who stop the practice[7,8,9]. It is unclear whether douching causes the alteration in vaginal microbiota, is initiated as a response to a change in microbiota and symptoms or is a confounder associated with an unknown risk factor. One way to assess the potential role of douching in altering the risk for UTI is to determine the impact of douching products on E. coli and commensal vaginal lactobacilli. In an effort to better understand how douching products impact the vaginal environment and potential risk for UTI, we co-cultured commercially available douches with the four most common vaginal Lactobacillus spp., E. coli and vaginal epithelial cells and measured the effect of douches on bacterial growth and human cell viability and cytokine production

Methods

Results

Conclusion