Monitoring research on the areas intensively and continuously affected by technogenic loading has remained topical until nowadays. The soil as a basic component of many ecosystems, including the structure of its microbial cenoses, remains an informative index of a system’s overall stability. The areas affected by railway transport have been scarcely studied. Due to the above, the aim of this work has been to establish the transformation regularities of soil microbial cenoses of territories close to railways and to establish the groups of microorganisms that are a sensitive criterion of technogenic vehicular influence. For the purpose of microbiological research, soil samples were taken at different distances from the railway track (0, 25, 50, 100 and250 m) within five monitoring sections of the Tchop – Uzhhorod – Sambor railway (in the territory of Zakarpatska oblast). The number of ecological trophic groups was identified by means of inoculation on nutrient media using the method of serial dilution of soil suspensions. The research showed that in all types of soils that were adjacent to railway tracks, the number of ammonifiers and spore microbiota was high due to the high content of heavy metals (beyond the background levels). Besides, the bacterial microflora on beef-extract agar was characterized by homogeneity with domination of enteric bacteria and spore bacteria. Simultaneously, the numbers of nitrogen-fixing microorganisms, micromycetes, oligonitrophils, amylolytic and pedotrophic microflorae were shown to be low compared to the control. Farther from the railway track, pigmental species of bacteria appeared in the soil samples, attesting to the activity of self-purification processes. Correlation analysis of the data showed that the soil microbiota of the railway-side areas was undergoing changes as affected by heightened contents of heavy metals. Existence of medium and close connections was established between the number of microorganisms of ecological trophic groups and the content of acid-soluble lead forms at the levels of 0.72–1.72 maximum permissible concentrations. It was the nitrogen-fixing microorganisms and microscopic fungi that showed a fast response to heavy metals, which was an indication of their possible use as indicators of the ecological state of technogenically transformed soils.

It is admitted that the normal human microflora plays an important role in supporting homeostasis, forming immune mechanisms and metabolism. Nowadays, there is a constant growth of different diseases due to microbiological imbalance in a human organism. Preparations containing “good bacteria” have been used for therapeutic purposes since ancient times. The mechanism of probiotics influence comprises their ability to compete for adhesion sites with the pathogens, to exhibit antagonistic activity and stimulate the immune system of a host. Most of probiotics commonly used are the spores of Bacillus. Initially the main focus of their use was the prevention of gastrointestinal disorders. So, the use of probiotics in dental practice is a poorly studied area. In recent years, probiotics have been investigated to provide the oral health. Therefore the study of using probiotics for correction of the oral microflora in people with inflammatory diseases of the periodontal tissues is promising. Our previous studies have shown changes in microbial community of an oral cavity in patients with periodontitis. In particular, the reducing number of obligate microorganisms and increasing number of pathogens was demonstrated. The paper describes the current data on the potential benefits and basic properties of the Bacillus spore probiotics, which demonstrate the viability and relevance in dental practice. The study tested antagonistic activity of commercial Bacillus probiotics "Biosporin" ("Biopharma", Ukraine), "Subalinum" ("Biopharma", Ukraine), "Normaflore" ("Sanofi-Aventis Zrt.", Hungary) and "Enterogermina" ("Sanofi-Synthelabo SpA", Italy) against clinical strains of microorganisms isolated from the oral cavity of patients with periodontitis. Thus, further studies on the role of spore probiotics in correction of the oral cavity microflora as a part of complex treatment of periodontitis should be carried out.