Resistance factor-mediated spectinomycin resistance.

Of 100 natural isolates of drug-resistant enteric bacteria, 51 were resistant to spectinomycin (Spc) and 46 contained transferable R factors mediating Spc resistance. All Spc(R) R factors mediated streptomycin and bluensomycin resistance and were fi(+) type. Extracts of R-Spc(R) strains adenylated Spc, dihydrospectinomycin, actinamine, streptomycin, and bluensomycin in vitro in the presence of adenosine triphosphate and Mg(++). Results of genetic and biochemical studies support the hypothesis that these reactions are mediated by a single enzyme.