Effect of commercial vaginal products on the growth of uropathogenic and commensal vaginal bacteria

Abstract

Half of postmenopausal women experience genitourinary syndrome of menopause, for which many use lubricating vaginal products. The effect of vaginal products on uropathogenic and commensal vaginal bacteria is poorly understood. We evaluated the effect of five common vaginal products (KY Jelly, Replens Silky Smooth lubricant, coconut oil, Replens Long-Lasting moisturizer or Trimo-San) on growth and viability of Escherichia coli and Lactobacillus crispatus. Bacteria were co-cultured products alone and in the presence of both vaginal epithelial cells and selected products. Bacterial growth was compared between conditions using an unpaired t-test or ANOVA, as appropriate. All products except for coconut oil significantly inhibited growth of laboratory and clinical strains of Escherichia coli (p < 0.02). Only two products (Replens Long-Lasting moisturizer and Trimo-San) significantly inhibited growth of Lactobacillus crispatus (p < 0.01), while the product Replens Silky Smooth stimulated growth (p < 0.01). Co-culture of selected products in the presence of vaginal epithelial cells eliminated the inhibitory effects of the products on E. coli. In conclusion, in vitro exposure to vaginal moisturizing and lubricating products inhibited growth of Escherichia coli, though the inhibition was mitigated by the presence of vaginal epithelial cells. Lactobacillus crispatus demonstrated less growth inhibition than Escherichia coli.

Figure 1

Change in bacterial growth with exposure to vaginal products. (a) Final change in growth, as measured by OD600, for laboratory strain of E. coli is similar to that for representative strain (F) of clinical E. coli across all test conditions (p > 0.05). (b) Final change in growth of L. crispatus, as measured in CFU (simple co-culture, without vaginal epithelial cells), demonstrating inhibition by Replens Long-Lasting moisturizer and Trimo-San (p < 0.01). L. crispatus growth was stimulated by Replens Silky Smooth (p < 0.01). As expected, methylparaben killed L. crispatus (p < 0.01), and lactic acid did not have a significant effect compared with control.

Figure 2

Change in bacterial growth with exposure to vaginal products in the presence of vaginal cells. (a) Final change in growth of E. coli, as measured in CFU (in 1:100 diluted product and KSF cell culture media as control), in the absence and presence of vaginal epithelial cells, demonstrating growth in Trimo-San and Replens Long-Lasting moisturizer in the presence of human cells (p < 0.05). (b) Final change in growth of L. crispatus, as measured in CFU (in 1:100 diluted product and MRS/KSF cell culture media as control), demonstrating a lack of inhibition by KY Jelly, Replens Long-Lasting moisturizer and Trimo-San, regardless of the presence of human vaginal epithelial cells (p > 0.05).