Transfer of erythromycin resistance from clinically isolated lysogenic strains of Streptococcus pyogenes via their endogenous phage.

Endogenous bacteriophage from clinically isolated, erythromycin-resistant strains of Streptococcus pyogenes, upon induction by treatment with mitomycin C, were demonstrated to cause transduction of antibiotic resistance yielding transductants resistant to relatively high concentrations of erythromycin. Transduction of resistance to erythromycin via endogenous phage may play a significant role in the emergence of streptococci with multiple resistance in the clinical environment.