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. 2006 Oct;72(10):6461-6.
doi: 10.1128/AEM.00271-06.

Biochemical and molecular characterization of tetracycline-resistant Aeromonas veronii isolates from catfish

Mohamed Nawaz  1 , Kidon Sung, Saeed A Khan, Ashraf A Khan, Roger Steele
Affiliations

Biochemical and molecular characterization of tetracycline-resistant Aeromonas veronii isolates from catfish

Mohamed Nawaz et al. Appl Environ Microbiol. 2006 Oct.

Abstract

Eighty-one tetracycline-resistant Aeromonas sp. strains were isolated from farm-raised catfish. Morphological and biochemical characteristics indicated that 23 of the 81 aeromonads were Aeromonas hydrophila, 7 isolates were Aeromonas trota, 6 isolates were Aeromonas caviae, 42 isolates were Aeromonas veronii, and 3 isolates were Aeromonas jandaei. However, the AluI and MboI restriction fragment length polymorphism (RFLP) patterns of the PCR-amplified 1.4-kb 16S rRNA gene from all 81 tetracycline-resistant aeromonads from catfish were identical to the RFLP banding patterns of A. veronii ATCC 35626, indicating that all 81 isolates were strains of A. veronii. A multiplex PCR assay successfully amplified the 5 tetracycline-resistant genes (tetA to E) from the genomic DNA of all 81 isolates. The assay determined that tetE was the dominant gene occurring in 73/81 (90.0%) of the aeromonads. Plasmids (2.0 to 20 kb) were isolated from 33 of the 81 isolates. Dendrogram analysis of the SpeI pulsed-field gel electrophoresis identified 15 distinct macrorestriction patterns among the isolates. Our results indicate the need for use of 16S rRNA in the identification of Aeromonas spp. and the prevalence of catfish as a reservoir of tet genes.

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Figures

FIG. 1.
FIG. 1.
(A) PCR amplification of the 1.4-kb 16S rRNA gene from representative strains. (B) AluI plus MboI RFLP profile of the 16S rRNA amplified from representative isolates of Aeromonas spp. from catfish. Lanes: 1 and 14, 100-bp molecular size markers; 2, A. hydrophila ATCC 7966; 3, A. veronii ATCC 35626; 4, A. caviae ATCC 13136; 5, A. trota ATCC 49661; 6, A. salmonicida ATCC 33659; 7, AVT 720; 8, AVT 429; 9, AHT 03; 10, AVT 61; 11, AJT 2; 12, AJT 1; 13, AJT 3.
FIG. 2.
FIG. 2.
Detection of tetracycline resistance determinants (tetA to E) by multiplex PCR in aeromonads isolated from catfish. Lanes 1 to 7, 100-bp ladder; lane 2, 211-bp tetA amplicon; lane 3, 391-bp tetB amplicon; lane 4, 897-bp tetC amplicon; lane 5, 844-bp tetD-amplified DNA; lane 6, 744-bp tetE-amplified DNA.
FIG. 3.
FIG. 3.
Plasmid profiles of tetracycline-resistant A. veronii isolates from catfish. Lanes 1 and 18 are plasmids of known sizes. Plasmids were from strains AE 11 (lane 2), Aht620 (lane 3), AE 2 (lane 4), Avt603 (lane 5), Aht1 (lane 6), Avt429 (lane 7), Avt620 (lane 8), Avt004 (lane 9), Aht22 (lane 10), Avt 720 (lane 11), Avt431 (lane 12), Aet603 (lane 13), Avt1031 (lane 14), AvtB6 (lane 15), Avt013 (lane 16), and Avt901 (lane 17).
FIG. 4.
FIG. 4.
SpeI PFGE of the genomic DNA of selected aeromonads isolated from catfish and the dendrogram analysis of the macrorestriction patterns by the bionumeric software.
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References

    1. Abbott, S. L., L. S. Seli, M. Carino, Jr., M. A. Hartley, and J. M. Janda. 1998. Misidentification of unusual Aeromonas species as members of the genus Vibrio: a continuing problem. J. Clin. Microbiol. 36:1103-1104. - PMC - PubMed
    1. Adams, C. A., B. Austin, P. G. Meaden, and D. McIntosh. 1998. Molecular characterization of plasmid-mediated oxytetracycline resistance in Aeromonas salmonicida. Appl. Environ. Microbiol. 64:4194-4201. - PMC - PubMed
    1. Andersen, S. R., and R. A. Sandaa. 1994. Distribution of tetracycline resistance determinants among gram-negative bacteria isolated from polluted and unpolluted sediments. Appl. Environ. Microbiol. 60:908-912. - PMC - PubMed
    1. Aquaculture Outlook. 2001. Livestock, dairy and poultry situation and outlook supplement. U.S. Department of Agriculture, Washington, D.C.
    1. Austin, B., and D. A. Austin. 1993. Bacterial fish pathogens: disease in farmed and wild fish, 2nd ed. Ellis Horwood, Chichester, United Kingdom.

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