Open AccessBiochemical and Molecular Characterization of Tetracycline-Resistant Aeromonas veronii Isolates from Catfish
Author(s) -
Mohamed S. Nawaz,
Kidon Sung,
Saeed Khan,
Ashraf A. Khan,
Roger Steele
Publication year - 2006
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.00271-06
Subject(s) - aeromonas , aeromonas veronii , tetracycline , biology , catfish , microbiology and biotechnology , restriction fragment length polymorphism , 16s ribosomal rna , vibrionaceae , pulsed field gel electrophoresis , aeromonas hydrophila , polymerase chain reaction , ribotyping , bacteria , gene , genetics , antibiotics , genotype , fish <actinopterygii> , fishery
Eighty-one tetracycline-resistantAeromonas sp. strains were isolated from farm-raised catfish. Morphological and biochemical characteristics indicated that 23 of the 81 aeromonads wereAeromonas hydrophila , 7 isolates wereAeromonas trota , 6 isolates wereAeromonas caviae , 42 isolates wereAeromonas veronii , and 3 isolates wereAeromonas 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 ofA. veronii ATCC 35626, indicating that all 81 isolates were strains ofA. veronii . A multiplex PCR assay successfully amplified the 5 tetracycline-resistant genes (tet A to E) from the genomic DNA of all 81 isolates. The assay determined thattet E 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 ofAeromonas spp. and the prevalence of catfish as a reservoir oftet genes.