Relation Between Kanamycin-Resistance and Streptomycin-Resistance of Bacteria. I with Special Reference to E. Coli B/r Strain

Abstract

Recently, with the introduction of various new antibiotics, a great advance has been made in the therapeutic field. However, on the other hand, the appearance of drug-resistance has posed a difficult problem, and 1s drawing much attention. The new antibiotic kanamycin (KM) discovered by Umezawa¹⁾ et al., is not an exception, and the relation between KM-resistance and streptomycin (SM)-resistance has been the subject of investigation by many researchers. However, their results are not always consistent. We think that this disparity of reasults is due to the fact that these investigators did not use the pure clone of the resistant mutants.

In order to clarify this relation between KM-resistance and SM-resistance, we have, checked the purity of resistant clones by the agar plating method at each step of resistance increase, and studies were made with these pure clones.