The Influence of Bacteriophage on Streptococcus pyogenes

Abstract

By the selective action of certain bacteriophages on cultures of susceptible streptococci it is possible to alter or enhance certain of their characteristics. The extractable M antigen may be greatly increased; non-mucoid strains may become completely mucoid with or without the increase in M antigen. Some phage-selected cultures have shown a marked increase in mouse virulence and some an ability to survive in normal human blood not possessed by the parent strain.