The Rationale for Probiotics in Female Urogenital Healthcare

Gregor Reid PhD MBA, BSc (Hons); Jeremy Burton PhD; Estelle Devillard PhD

In This Article

The Protective Role of the Commensal Vaginal Microbiota

Culture-based methods followed by molecular typing have shown Lactobacillus crispatus and L jensenii to be the dominant organisms in most healthy, premenopausal women.[40] However, use of denaturing gradient gel electrophoresis without culture has recently identified the strict anaerobe L iners as the most common habitant, at least in 1 primarily white population.[41] After menopause, some 25% to 30% of women still have lactobacilli present, and this number rises to between 60% and 100% with use of vaginal or oral estrogen-replacement therapy.[42,43,44,45] Correspondingly, rates of UTI and vaginal infections increase with age and decrease with estrogen-replacement therapy.

Although oral and vaginal sex can lead to vaginal infections, many cases of vaginitis and UTI arise from ascension of the person's own microorganisms. The net effect of ascension of these "abnormal" microorganisms is creation of a vaginal environment in which lactobacilli occur in low concentrations or are absent and are replaced by pathogenic Gram-positive cocci, Gram-negative rods, or yeast. Clinical implications of the distinction between "normal" and "abnormal" microbiota were noted more than 30 years ago in studies of the role of the normal microflora in protecting the host.[46,47] The fluctuations between a normal and an abnormal (and potentially unhealthy) vaginal environment have more recently become a focus of investigation by other groups.[48,49] An analysis of the vaginal microflora over the course of the menstrual cycle has shown that only 22% women maintain a lactobacilli-dominated flora,[50] and although epithelial cell receptivity to lactobacilli adhesion increases at peak estrogen levels midcycle,[51] it is still not clear what factors cause such a dramatic alteration in the flora.

The concept of a protective role for the microflora normally found in a healthy vagina is the basis for the research on application of beneficial bacteria to the vagina, and the positive results obtained in recent studies[15,52,53] point to a future in which probiotics will soon be an option for vaginal healthcare.


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