Inhibition of dihydrostreptomycin binding to Mycobacterium smegmatis by monovalent and divalent cation salts.

To better understand salt antagonism of dihydrostreptomycin (DSM) action on Mycobacterium smegmatis, the effects of monovalent and divalent cation salts on drug uptake were studied in relation to the lethal activity of DSM. In Sauton liquid medium NaCl, MgCl(2), and SrCl(2) inhibited the initial instantaneous binding of [(3)H]DSM to the organism and suppressed secondary uptake. These data correlated well with the capacity of each salt to prevent the lethal activity of DSM. It was concluded that monovalent and divalent cation salt antagonism of DSM action on M. smegmatis involves nonspecific interference with drug uptake.