Molecular characterization of tetracycline- and quinolone-resistant Aeromonas salmonicida isolated in Korea |
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| Authors: | Ji Hyung Kim Sun Young Hwang Jee Soo Son Jee Eun Han Jin Woo Jun Sang Phil Shin Casiano Choresca Jr Yun Jaie Choi Yong Ho Park Se Chang Park |
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| Institution: | 1Laboratory of Aquatic Animal Medicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea.;2Department of Microbiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea.;3Laboratory of Animal Cell Biotechnology, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea. |
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| Abstract: | The antibiotic resistance of 16 Aeromonas (A.) salmonicida strains isolated from diseased fish and environmental samples in Korea from 2006 to 2009 were investigated in this study. Tetracycline or quinolone resistance was observed in eight and 16 of the isolates, respectively, based on the measured minimal inhibitory concentrations. Among the tetracycline-resistant strains, seven of the isolates harbored tetA gene and one isolate harbored tetE gene. Additionally, quinolone-resistance determining regions (QRDRs) consisting of the gyrA and parC genes were amplified and sequenced. Among the quinolone-resistant A. salmonicida strains, 15 harbored point mutations in the gyrA codon 83 which were responsible for the corresponding amino acid substitutions of Ser83→Arg83 or Ser83→Asn83. We detected no point mutations in other QRDRs, such as gyrA codons 87 and 92, and parC codons 80 and 84. Genetic similarity was assessed via pulsed-field gel electrophoresis, and the results indicated high clonality among the Korean antibiotic-resistant strains of A. salmonicida. |
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| Keywords: | Aeromonas salmonicida minimal inhibitory concentration pulsed-field gel electrophoresis quinolone-resistance determining region tetracycline-resistance |
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