STUDY OF THE EFFECT OF SHUNGITE ON MICROORGANISMS

The Enterobacteriacea was represented by Е. Coli, as nonpathogenic for humans but important as indicating the water’s sanitary condition, and Salmonella enteritidis, as a pathogenic microorganism causing salmonellosis in humans and animals.

Pathogenic for humans corynebacteria were represented by Corynebacterium diphtheria (toxigenic) being of great epidemiological importance in terms of spreading and increasing the number of diphtheria cases in Russia today. Besides, diphtheria infection rates in Tula Region are many times as high as in The Republic of Karelia. Opportunistic pathogenic microorganisms were represented by Staphilococcus auretzs and Candida albicans, a fungus playing an important role in pathologies in humans and animals.

Shungite powder (5 and 10 g) was put into two 250-gram glass flasks and was sterilized at 1 atm. for 30 minutes. Sterilized saline was added to the sterilized shungite to make two 100 ml 5 and 10 % shungite solutions under the physiological conditions allowing the microorganisms to survive. The control solution was a shungite-free physiological solution. A suspension of microorganisms was added to the solutions. Strain preparation was performed in accordance with the recommendations for growth medium biological parameters control (Moscow, 1980) [3].

18-20-hour cultures of the test strain which did not pass more than three passages in the growth media were used in the experiment. One-day cultures of the test strains were washed off with saline ensuring an optic turbidity standard of 10 units (one billion of microbial cells per ml). The initial standard suspension was used to make tenfold solutions by means of diluting by putting 0.5 ml of the culture into 6 tubes with 4.5 ml of saline and mixing it thoroughly. Each time a new dropper was used. A number of serial solutions were received, from 10^-1 to 10^-6 cells per ml. Then, 1 ml of the 10^-4 suspension (equal to 100,000 microbial cells per ml) was added into 100 ml of the shungite physiological solution with and without shungite. The inoculation dose was 1,000 cells per ml in the experimental samples. The shungite and microorganism suspension experimental samples were left at room temperature (22-23 ⁰С), and 24 and 48 hours later inoculation of solid growth media with 0.1 ml of the suspension was done based on the growth of each microorganism: Endo agar, Egg-yolk salt agar, Sabouraud’s agar, and blood agar. The results of the experiment are shown in the table below.

Table

The effect of shungite on the survival rates of microorganisms