INHIBITION OF THE BACTERIAL GROWTH IN THE CULTURES OF STREPTOCOCCUS PYOGENES AND STREPTOCOCCUS AGALACTIAE IN PRESENCE OF COPPER AND ZINC IONS

Aim. The work was performed with the purpose to study antibacterial action of millimolar concentrations of copper and zinc ions, used as sulfates or chlorides in the cultures of S.pyogenes and S.agalactiae. Materials and methods. Suspensions of the S.pyogenes and S.agalactiae bacteria which contained 10⁸ CFU/ml were sown by the lawns into the standard Petri dishes coated with the supplemented Nutrient Agar. 30 min later the salt solutions of copper or zinc were added by the 5 pi drops on the surfaces of the lawns with use of 36-channel stamp replicator. The salt solutions contained copper or zinc at the concentrations ranged between 5xl0^-3 M to 5xl0^_1 M of the metals. Then the dishes containing bacterial cultures were incubated for 24 hrs at 37°C followed by measuring diameter of the area of culture growth inhibition. The probes of material obtained from the centers of the stunting areas were passed into the centrifuge tubes with the supplemented Nutrient Broth, incubated for up to five days at 37°C and tested for the Broth clarity. Results. In presence of the metal concentrations ranged between 50 to 500 mM the inhibitory action of zinc sulfate towards S.pyogenes bacteria was 1.5 - 1.7 times higher (p<0.001) than the action of copper sulfate. In presence of 100 and 500 mM of the metals the action of zinc chloride was 1.2 - 1.3 limes higher (p<0.05 - 0.1) than the effects of copper chloride. In presence of 100 and 500 mM of copper used as chloride its antibacterial action towards S.agalactiae bacteria was 8 - 13 per cent higher (p>0.1) than the effects of zinc chloride. Passages of the material obtained from the areas of culture growth inhibition demonstrate clarity of the Broth in 67 - 85 per cent (S.pyogenes) or 48 - 67 per cent (S.agalactiae) probes with samples from the areas treated with copper salts, and in 30 per cent probes with samples from the areas treated with the salts of zinc. Conclusion. Inhibitors’ action of copper and zinc ions used in millimolar concentrations in the cultures of S.pyogenes and S.agalactiae was established. S.pyogenes, bacteria demonstrate higher than S.agalactiae sensitivity to the action of zinc ions measured by the area of the growth inhibition. Also, in a comparison with S.agalactiae, the S.pyogenes bacteria undergo bactericidal action of zinc ions in a higher part of observations.

S.pyogenes, S.agalactiae, antibacterial action, copper, zinc, S.pyogenes, S.agalactiae