Phenotypic and genotypic characterization of tetracycline- and oxytetracycline-resistant Aeromonas hydrophila from cultured channel catfish (Ictalurus punctatus) and their environments.

摘要: Oxytetracycline-resistant (OTcr) and tetracycline-resistant (Tcr) Aeromonas hydrophila were isolated commonly from catfish intestinal contents the water sediment of culture ponds, but less frequently in market catfish. Isolates demonstrated two resistance phenotypes, Tcr OTcr Tcs OTcr, when plated directly on to MacConkey agar containing 30 micrograms tetracycline or oxytetracycline per ml. isolates expressed after induction by 1 h growth tryptic soy broth microgram Over 90% resistant aeromonads hybridized with DNA probes for class A E determinants; was twice as prevalent A. The distribution determinants varied phenotypes. Prior induction, 86% well while only 16% determinant Tcr. Three 5 without 14 transferred Escherichia coli.