In-vitro-Studie über die Wirksamkeit der Bacteriocine von Streptococcus salivarius zur Inhibition von Streptococcus pyogenes

This dissertation concentrates on an alternative mechanism of inhibition of the human pathogenic bacterium S. pyogenes by use of a probiotic, that is in administration in New Zealand since almost four years. This probiotic named “Throat Guard” contains S. salivarius ssp. salivarius K12 and its bacteriocin Salivaricin A2 in the form of lozenges , that protect against pharyngeal infections and rare complications as the acute rheumatic fever and the acute glomerulonephritis. Because of the broad range of S. pyogenes serotypes predominant strains that occur in Germany should be tested upon their susceptibility to the bacteriocin. For these purposes we arranged in-vitro tests in liquid media and on solid ground to give consideration to the physiological conditions in the pharynx with its mucous membranes and saliva. In liquid media S. salivarius ssp. salivarius K12 was cultured in different ratios of 20:1, 2:1 and 1:1 to the antagonistic patogen to find out the dominating bacterium (K12 or S. pyogenes). Furthermore more than 80 S. pyogenes strains were examined via deferred antagonism tests on Columbia Agar plates to detect an inhibition potential by S. salivarius ssp. salivarius K12. All strains, less invasive strains as well as fatal pathogens, were identically susceptible to the bacteriocin. No resistances could be detected; merely a reversible adaption towards the inhibitory substance could be detected. Other S. salivarius strains were proved to be less or even not able to inhibit the pyogenic bacteria. Thus the investigations of this dissertation affirm the efficacy of this new dietary supplement that is applied in New Zealand as an alternative treatment of S. pyogenes infections. So the immense investments to establish a vaccination against S. pyogenes and the risk of developing an autoimmunity and of an increasing resistance to antibiotics could be minimized. In the meantime a S. salivarius ssp. salivarius K12 containing mouthwash is prearranged in Germany, too. But the appliance of bacteria in the form of lozenges or drugs in general still remains difficult in our country