Genetic mapping in Bacillus subtilis 168 of the aadK gene which encodes aminoglycoside 6‐adenylyltransferase

Bacillus subtilis 168 has an aadK gene, which encodes aminoglycoside 6‐adenylyltransferase, a streptomycin‐modifying enzyme, on its chromosome. To characterize the aadK gene, we con tructed a B. subtilis 168 strain that carried the chloramphenicol resistance gene near the aadK on the chromosome and an aadK deletion mutant using an integration technique. The aadK gene was mapped between azlB and pheA on the chromosome of B. subtilis 168. The aadK deletion mutant was slightly more susceptible to streptomycin than the original strain. The result indicates that the aadK gene contributes low‐level resistance to streptomycin in B. subtilis 168.