Detection of R+ Bacteria in Cultured Marine Fish, Yellowtails (Seriola quinqueradiata)

Abstract

Many drug‐resistant gram‐negative bacilli were isolated from the intestinal tracts of yellowtails (Seriola quinqueradiata) cultured on farms in various parts of Kochi and Ehime Prefectures, Shikoku Island. They were Vibrio, Pseudomonas, Proteus, Citrobacter and some unidentified Enterobacteriaceae. Of these drug‐resistant strains, Vibrio and Pseudomonas were found to carry R factors in high frequencies. These R factors had four types of resistance markers, SA, SA. CM, SM. CM. ABP. and SA. SM. CM. TC. All R factors were found to belong to the fi– type. In contrast, only one drug‐resistant gram‐negative bacillus was detected in a cultured yellowtail on farms near Numazu City, Shizuoka Prefecture. © jointly owned by author and Igakushoin (Publisher)