Effects of streptomycin and novobiocin on Staphylococcus aureus gene expression

Streptomycin and novobiocin induced production of protein A and inhibited production of alpha- and beta-hemolysins in mutants of Staphylococcus aureus strains RN450 and RN1 resistant to these antibiotics. Streptomycin, but not novobiocin, also inhibited propagation of bacteriophages of serological group B, whereas phages of group A were unaffected. Streptomycin had to be present at adsorption of the phage, and 10 mM CACL2 reversed the inhibitory effect. Lysogenization and competence induction occurred in the presence of streptomycin, suggesting that some early phage genes were expressed.