抄録
Considerable fractions of gram-negative bacilli, Aeromonas liquefaciens, A, salmonicida, Pseudomonas, Hafnia and unidentified Enlerobacteriaceae, isolated from the intestinal tracts of cultured Amago (Oncorhyuchus rhodurus macrostomus) from 23 Amago-ponds and of Yamame (O. masou ishikawae) from one pond as well as the water of 3 ponds in Shiga, Gifu and Nagano Prefectures and Tokyo Metropolis in Japan were found to be multiple-drug-resistant. Of those drug-resistant strains, A. salmonicida and A. liquefaciens carried R factors at high frequencies and to be prevalent in many Amago ponds throughout Japan. Thcsc R factors had markers of resistance to SA, SA. TC, SA. SM.CM. All the R factors belonged to fi-type.
