Observations on the Action of Streptomycin in vitro (II).

Abstract

The presence of 1 to 5% or more horse or human serum enhances the resistance of Streptococcus hemolyticus, S. viridans, Diplococcus pneumoniae, and certain strains of Staphylococcus aureus. Serum in concs. of 1-5% has no effect on the sensitivity of Escherichia coli, Eberthella typhosa, Klebsiella pneumoniae, or Aerobacter aerogenes to streptomycin. Higher concs. of serum may at times enhance the action of streptomycin on certain of these organisms. Streptomycin is effective under certain conditions against stationary or slowly dividing cells, as well as against rapidly dividing cells, providing a sufficient conc. of the drug is used. No direct correlation between the rate of growth of an organism with and without serum and the effect of serum on the sensitivity of an organism to streptomycin can be made at this time.