PROBIOTIC STRAINS OF LACTOBACILLI HAVE PROPHYLACTIC EFFECT ON THE MODEL OF EXPERIMENTAL VAGINITIS
Babenko L, Lazarenko L, Bubnov R, Spivak M.
D.K. Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine,
Department of interferon and immunomodulator problems
Despite the constant increase in the number of antibiotics and antiviral drugs, as well as expansion of their spectrum of action and therapeutic efficacy, the number of infectious diseases of the urogenital system, according to statistics, not only does not decrease, but on the contrary rapidly increases (Kenyon, 2017). Therefore, the development of alternative means for prevention and treatment of urinary tract infections and vaginosis that involve the use of natural products with an antagonistic effect on infectious agents and the ability to balance the immune response is relevant. Such means are the latest probiotic drugs, created on the basis of representatives of normal microbiota – non-pathogenic lactic acid bacteria with antibacterial and immunomodulatory properties (Reid, 2018; MacPhee, 2019). The aim of the work was to determine the prophylactic action of Lactobacillus casei IMV B-7280 and L. acidophilus IMV B-7279 probiotic strains on the model of experimental vaginitis induced by Staphylococcus aureus 8325-4. In this work, the drug “Labilact®” (SPA “Ariadna”, Ukraine) was used for comparison. A suspension of probiotic in 0.15 M NaCl was injected into vagina of female BALB/c line mice at a dose of 1·106 cells/animal once per day for 7 days. After completing the course of prophylactic administration of probiotics, S.aureus 8325-4 was administered into vagina of mice in order to simulate staphylococcal vaginitis. To determine the spectrum of microbiota, aliquots from the vagina were plated on eight selective nutrient media. The infection of mice with S. aureus 8325-4 strain was found to cause an imbalance of vaginal microbiota, as evidenced by an increase in the number of opportunistic microorganisms and a decrease in the amount of lactobacilli and bifidobacteria. S. aureus 8325-4 was detected in the vagina of mice that did not receive probiotics (control group) in a constant amount throughout the observation period. At the same time S. aureus 8325-4 was completely eliminated from the vagina of infected mice that obtained L. casei IMV В-7280 (on the 6th day) or L. acidophilus IMV B-7279 (on the 12th day). Preventive administration of the “Labilact®” drug did not decrease the number of S. aureus 8325-4 in the vagina of mice throughout the observation period. In the vagina of infected mice that did not receive probiotic strains, there was a smaller amount of lactobacilli and bifidobacteria compared to intact mice. The number of lactobacilli increased in the vagina of infected mice receiving L. casei IMV B-7280 (on the 1st-12th days), L. acidophilus IMV B-7279 (on the 6th-9th days) and the “Labilact®” drug (only on the 6th day) compared to the control group. After administration of probiotic strains to mice, the number of bifidobacteria in the vagina was also higher than in the control group, during the observation period, and after the introduction of the drug “Labilact®” – only on the 6th and 12th days. The number of opportunistic bacteria decreased in mice that obtained L. casei IMV B-7280. However, the number of microscopic fungi increased in the vagina of mice treated with L. acidophilus IMV B-7279 on the 1st-12th days, and in those treated with the drug “Labilact®” – on the 3rd-6th days. Target probiotic strain L. casei IMV B- 7280 is promising for the creation of highly effective novel probiotic drugs that can be used for the directed prevention of infectious and inflammatory diseases of the genitourinary system caused by pathogenic and opportunistic microorganisms. Preventive action of L. acidophilus IMV B-7279 and the drug “Labilact®” for bacterial vaginitis in mice was less effective.