Vaginal and Rectal Colonization of Lactobacillus Crispatus NTCVAG04 Following Oral Administration in Patients With History of Vaginitis/Vaginosis

In fertile, premenopausal healthy women, the vaginal ecosystem is dominated by Lactobacillus spp., but a diverse array of other bacteria can be present in much lower numbers. Over 120 species of Lactobacillus have been identified and more than 20 species have been detected in the vagina. Molecular-based techniques have demonstrated that healthy vaginal microflora does not contain high numbers of many different species of Lactobacillus. Rather, one or two lactobacilli from a range of three or four species (mainly L. crispatus and L. iners but also L. jensenii and L. gasseri) are dominant, whereas other species are rare, lower in titer and tend to be novel phylotypes.

Vaginitis is defined as a spectrum of conditions that cause vaginal and sometimes vulvar symptoms such as itching, burning, irritation, odor and vaginal discharge. Infection is the most common cause of vaginitis, including bacterial vaginosis (BV), vulvovaginal candidiasis and trichomoniasis. Bacterial vaginosis is a very common microbiological disturbance of the vaginal environment in adult women and is characterized by a depletion of lactobacilli in favor of an overgrowth of anaerobic bacteria. Colonization by L. crispatus or L. jensenii is associated with a lower frequency of bacterial vaginosis, and L. crispatus is strongly correlated with the absence of BV, low pH, negative whiff test, absence of clue cells and normal vaginal discharge.

Although antibiotic treatment of BV is strongly recommended, attempts at improving the efficacy of therapy are still a matter of debate. In fact, antimicrobial treatment of urogenital infections is not always effective, and problems remain due to bacterial and yeast resistance, recurrent infections and side effects. Alternative remedies are thus of interest and many studies have provided evidence of the beneficial functions of the human microbiota and prompted the selection of bacterial strains with health-promoting capacities for the treatment of conditions in which the microbiota, or its optimal functioning, is altered. The rationale for the use of probiotics in women is based on the genitourinary regulatory role played by the healthy vaginal microbiota and the need for restoration of this microbial ecosystem after insult.

Until today, the most common way of delivering probiotic lactobacilli was the administration of vaginal suppositories.However, this route will no longer be acceptable as products containing probiotics (live microorganisms) are not admissible as medical devices as per European Medical Device Regulation (EU) 2017/245. Oral administration therefore represents an alternative and more patient-friendly concept for the restitution of the normal vaginal microbiota. Indeed, several studies demonstrated the ability of rectal bacteria to move from the intestinal tract to the vagina. Moreover, it was recently demonstrated that the administration of a yoghurt containing Lactobacillus spp. including L.. crispatus in addition to antibiotic treatment may improve recovery rate and symptoms of BV and is well tolerated.

It is therefore reasonable to suppose that the oral administration of a food supplement containing an adequate concentration of a strain of L. crispatus, one of the predominant species, in the vaginal microbiota in asymptomatic women, may promote the re-colonization of the vaginal environment. Since this species is so representative and crucial in maintaining a healthy vaginal environment, we believe that it is of utter importance to understand its activity to fully disclose its potential.