Studies on the Reciprocal Action of Antibiotics III. The reciprocal action of antibiotics to the drug-resistant strain of Staphylococcus aureus (Terashima)

In this report, the effect of combinative administrations of antibiotics on the drugresistant strains of Staphylococcus aureus (Terashima), and the acquisition of cross-resistance were also studied. The results are as follows: 1) To the 5 γ/ml and 10 γ/ml of penicillin-resistan strain, the following combinations are all co-operative; penicillin and streptomycin, penicillin and aureomycin, penicillin and terramycin, and penicillin and chloromycetin. 2) To the 50 γ/ml and 100 γ/ml of streptomycin-resistant strain, the following combinations are all co-operative; streptomycin and penicillin, streptomycin and chloromycetin, streptomycin and terramycin, and streptomycin and aureomycin. 3) To the 10 γ/ml of aureomycin-resistant strain, the following combinative administrations are all co-operative; aureomycin and penicillin, aureomycin and streptomycin, aureomycin and terramycin, and aureomycin and chloromycetin. 4) To the 5 γ/ml of chloromycetin-resistant strain, the following combinative administrations are all co-operative; chloromycetin and penicillin, chloromycetin and streptomycin, chloromycetin and terramycin, and chloromycetin and aureomycin. 5) The penicillin-resistant strain is not resistant to streptomycin, aureomycin, terramycin and chloromycetin. 6) The streptomycin-resistant strain is not resistant to penicillin, aureomycin, terramycin and chloromycetin. 7) The aureomycin-resistant strain is not resistant to penicillin, streptomycin and chloromycetin, but is resistant to terramycin. 8) The chloromycetin-resistant strain is not resistant to penicillin and streptomycin, but is resistant to aureomycin and terramycin