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The influence of oestrogen on vaginal lactobacilli abundance

 

Given the positive influence of oestrogen on vaginal lactobacilli abundance, postmenopausal women experience a decrease in vaginal lactobacilli and increase in vaginal pH with increased incidence of Urinary Tract Infections (UTIs) due to increased colonisation by enterobacteria. Clinical symptoms include vaginal dryness, burning, itching, dyspareunia, dysuria, urinary frequency, and recurrent UTIs.1,2

The Genitourinary Symptoms of Menopause (GSM) are particularly common in women with breast cancer due to chemotherapy and oestrogen deprivation therapy. Vaginal oestrogen therapy increases vaginal lactobacilli and decreases colonisation by UPEC to reduce UTI recurrence, but oestrogen treatment for women with breast cancer is used with restraint due to frequent oestrogen sensitivity of the tumor.3,4 Thus, an appropriate probiotic intervention would be an alternative therapeutic option to enhance vaginal lactobacilli to discourage vaginal dysbiosis and recurrent UTIs.

Indeed, in a proof-of-principle pilot study, twice daily oral supplementation with the multi-strain probiotic formulation (2 X 2.5 billion live cells/dose) for two weeks in postmenopausal women with breast cancer receiving chemotherapy, with vaginal atrophy and an intermediate vaginal microbiota (Nugent score 4 – 6) (n = 11/group), improved the Nugent score (-1.3) towards a normal microbiota (< 3), whereas there was a deterioration in the control group receiving placebo (+0.45).

One week post-discontinuation, the Nugent score regressed in those women previously receiving the probiotic intervention (to only -0.57 from baseline) and further deteriorated in the control group (+2.5 from baseline), suggesting the protective effect of the probiotic intervention is not sustained with discontinuation in this at-risk group.

 

REFERENCES 1. Pandit L, Ouslander JG. Postmenopausal vaginal atrophy and atrophic vaginitis. Am J Med Sci 1997, 314:228-231. 2. Raz R, Stamm WE. A controlled trial of intravaginal estriol in postmenopausal women with recurrent urinary tract infections. N Engl J Med 1993, 329:753-756. 3. Krychman ML, Katz A. Breast cancer and sexuality: multi-modal treatment options. J Sex Med 2012, 9:5-13; quiz 14-15. 4. Marschalek J, et al. Influence of orally administered probiotic Lactobacillus strains on vaginal microbiota in women with breast cancer during chemotherapy: A randomized placebo-controlled double-blind pilot study. Breast Care 2017, 12:335-339

 

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