3"-phosphoryldihydrostreptomycin produced by the inactivating enzyme of Pseudomonas aeruginosa.

Escherichia coli carrying R factor was reported by Umezawaet al.l\ and Takasawa et al.2) to produce an enzyme adenylylating streptomycin, and E. colt carrying another R factor was reported by Ozanne et al.3) to produce an enzyme phosphorylating streptomycin. Though a resistant Pseudomonas was also observed by Doi et al.^ to produce an enzymeinactivating streptomycin in the presence of both ATPand Mg++, the structure of the inactivated streptomycin produced by the enzyme of this organism was not studied. We have found5) Pseudomonas aeruginosa TI-13 (isolated from a patient) to contain a soluble enzyme fraction which inactivates both streptomycin and dihydro-