In vitro and In vivo Effects of Deoxyribonucleic Acid Degradation Products on Virulent and Avirulent Group A Streptococci

Abstract

SUMMARY: A deoxyribonuclease-treated deoxyribonucleic acid (DNase and DNA), further supplemented with all eight of the naturally occurring deoxynucleo-sides and deoxynucleotides enhanced the rate and extent of multiplication of several virulent strains of group A β-haemolytic streptococci (Streptococcus pyogenes) without affecting the multiplication of related avirulent strains. Ribonucleic acid (RNA) degradation products or yeast extract did not exert such selective effects. An enhancement of DNA synthesis occurred in suspensions of virulent strains augmented with the DNA degradation products, whereas avirulentstrains did not respond. In addition, DNA synthesis was enhanced selectively in comparison to RNA and protein syntheses. The rate at which mice succumbed to infection by streptococci was enhanced considerably by the DNA degradation products, but the LD 50 remained unchanged.