@article{oai:nagasaki-u.repo.nii.ac.jp:00019425, author = {森井, 秀昭 and 大場, 崇徳 and 孟, 飛 and 金井, 欣也}, journal = {長崎大学水産学部研究報告, Bulletin of the Faculty of Fisheries, Nagasaki University}, month = {Mar}, note = {Conjugative transferability of various drug resistances was investigated in the fish pathogen Edwardsiella tarda isolated from freshwater fishes (mainly Japanese eel) and marine fishes (mainly Japanese flounder). The E. tarda isolates were resistant to ampicillin (Ap), chloramphenicol (Cm), kanamycin (Km), nalidixic acid (Na), furazolidone (NO, oxolinic acid (Oa) , sulfamononethoxine (Su), tetracycline (Tc, including doxycycline and oxytetracycline), and trimethoprim (Tmp) and susceptible to cephalexin, erythromycin, and streptomycin. The most of the 185 isolates was resistant in the isolates from the eel and susceptible in those from the flounder. Resistances to Ap, Km, and Tmp were harbored only in the isolates from the flounder and resistances to the other drugs were possessed mostly in those from the eel. Resistances to Cm, Km, Su, and Tc were transferred at transfer frequencies of 10-4 to 104 but the other resistances were not transferred to the recipient Escherichia coli k-12 X1037 strain. Additionally, the isolates harboring the transferable resistances were mostly collected from the eel. A single plasmid was harbored in the isolates with Cm, Km, Su, and/or Tc resistances and transferred to the recipient. Restriction enzyme Pst I and Hind III digestion patterns of plasmid in E. tarda were different between plasmids from the eel and the flounder, suggesting that the origin of R plasmids in E. tarda is different between the eel and the flounder. The molecular weight of the transferred R plasmid was estimated as 81 kb from the length (25.5 II m) in electron micrograph of a transferable plasmid., 長崎大学水産学部研究報告 v.88 p.109-118; 2007}, pages = {109--118}, title = {魚病原細菌Edwardsiella tardaの薬剤耐性とその伝達性}, volume = {88}, year = {2007} }