Presently lactic bacteria are divided into three phylogenetic groups: L.delbrueckii, L.casei-Pediococcus, Leuconostos.
Lactic bacteria number 56 species, 11 genera (Lactobacillus, Lactococcus, Leuconostos, Camobacterium, Enterococcus, Streptococcus, Pediococcus, Tetragenococcus, Vagococcus, Oenococcus, Veissella). Lactic bacteria are vegetative gram-positive facultative and strictly anaerobic rod-shaped bacteria. Parturient canals and breast milk (about 49% of the maternity patients have lactic bacteria in their breast milk) form the source of lactic bacteria, which colonize the gastrointestinal tract of infants. Lactic bacteria enter into complicated relations with other microorganisms, which result in suppression of the putrefactive and pyogenic bacteria. Antibacterial activity of lactic bacteria is associated with their forming the antibiotic-like substances (bacteriocins), production of lactic acid, alcohol, lysozyme in the process of carbohydrate hydrolysis. At the same time, many strains of lactic bacteria inhabiting the human intestines are capable of synthesizing the lactacines helpful in their competition with other lactacine-sensitive strains of lactic bacteria.
The lactic bacterium products are widely used in the gastroenterological practice, because they:
• prevent the progress of colitis, including the ulcerative colitis (reduction of the activity of myeloperoxidase ferment)
• colonize the protective layer of mucosa without penetration in crypts (suitable for treatment of nonspecific ulcerative colitis)
• produce the inhibitory action on Helicobacter pylori
Recently the data have been obtained with relation to the anti-tumor activity of lactic bacteria, which mechanism is probably also connected to the bacteriocin action:
• L. аcidophilus exhibits the expressed anti-tumor activity in relation to malignant neoplasms in the intestines;
• L. casei features the highest anti-tumor activity in relation to sarcomas.
• Prescription of L. casei to 58 patients with bladder cancer reduced the risk of tumor backset 1.8 times within a year after the completed specific treatment as compared with the control group.
The data have been obtained with respect to the action of bifidus and lactic bacteria on arterial tension. Reduction of the arterial tension was noted in the course of treatment of the hypertensive patients with B.bifidum, B.infantis, B. breve, B. adolescentis, B.longum, L. casei, L. helveticus. It is anticipated that substance SG-1 (the polysaccharide-peptidic complex of bacterial origin) features the hypotensive effect. At oral administration of SG-1 in the dose from 1 to 10 mg/kg of weight the arterial tension has been considerably decreased [R. Tanaka (1995)].