Plasmid-Determined Resistance to Erythromycin: Comparison of Strains of Streptococcus faecalis and Streptococcus pyogenes with Regard to Plasmid Homology and Resistance Inducibility

Streptococcus faecalis strains DS-5 and Streptococcus pyogenes strain AC-1 both have a 17 million dalton plasmid that determines resistance to erythromycin, lincomycin, and vernamycin B(alpha). The results of deoxyribonucleic acid-deoxyribonucleic acid hybridization experiments indicate that the two plasmids are about 95% homologous. It was also shown that erythromycin resistance is inducible in AC-1 and constitutive in DS-5.