Occurrence of tetracycline resistance genes in aquaculture facilities with varying use of oxytetracycline.
ABSTRACT The contribution of human activities to environmental reservoirs of antibiotic resistance is poorly understood. The purpose of this study was to determine if oxytetracycline (OTC) use in aquaculture facilities increased the detection frequency (i.e., prevalence) of tetracycline resistance (tet(R)) genes relative to facilities with no recent OTC treatment. We used polymerase chain reaction to screen water and sediment from four noncommercial fish farms in northwestern Wisconsin for the presence of ten tet(R) determinants: tet(A), tet(B), tet(D), tet(E), tet(G), tet(M), tet(O), tet(Q), tet(S), and tet(W). Water from farms with recent OTC use had significantly higher tet(R) detection frequencies than did water from farms without recent OTC use, with prevalence in raceways and rearing ponds of farms with recent OTC use exceeding by more than twofold that of farms not using OTC. Effluent from all farms, regardless of treatment regime, had higher tet(R) detection frequencies than their corresponding influent for all genes, but the specific combinations of tet(R) genes detected in a sample were not different from their corresponding influent. Although OTC use was associated with the increased occurrence and diversity of tet(R) genes in water samples, it was not found to relate to tet(R) gene occurrence in sediment samples. Sediment samples from facilities with no recent OTC use had significantly higher frequencies of tet(R) gene detection than did samples from facilities with recent OTC use. All of the tet(R) genes were detected in both the medicated and nonmedicated feed samples analyzed in this study. These findings suggest that both OTC treatment in aquaculture facilities and the farms themselves may be sources of tet(R) gene introduction to the environment. To our knowledge, this is the first study to use genotypic and cultivation-independent methods to examine tet(R) gene occurrence associated with OTC use in aquaculture.
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ABSTRACT: Aquaculture health management demands a constant growth in the production by stabilizing economic loss and implementing various natural plant-based bio products for treating pathogenic bacteria. Pathogenic effects of the Citrobacter freundii isolated from fingerlings of Tilapia collected from a fish farm showed symptoms like tail necrosis, septicemia, hemorrhage, and reddening of the body. Antibacterial activity of C. freundii was tested against various medicinal plants. Of the three plants screened, Azadirachta indica (Neem) showed good antibacterial activity against C. freundii. The present study revealed that A. indica plant extract at a concentration of 150 mg/l in vivo can be used as an alternative to antibiotics for treating this bacterial infection. The use of medicinal plant extract-mediated treatment was found to be very effective in controlling this bacterial infection.Aquaculture 02/2015; 437. DOI:10.1016/j.aquaculture.2014.12.008 · 1.83 Impact Factor
- Microbial pathogens and strategies for combating them: science, technology and education, Edited by A. Méndez-Vilas, 12/2013: chapter Detection of antibiotic residues in food – pitfalls and optimization of agar diffusion tests in comparison with commercial test kits.: pages 359-366.; Formatex, Spain.., ISBN: 978-84-939843-9-7
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ABSTRACT: Consumer demand for affordable fish drives the ever-growing global aquaculture industry. The intensification and expansion of culture conditions in the production of several finfish species has been coupled with an increase in bacterial fish disease and the need for treatment with antimicrobials. Understanding the molecular mechanisms of antimicrobial resistance prevalent in aquaculture environments is important to design effective disease treatment strategies, to prioritize the use and registration of antimicrobials for aquaculture use, and to assess and minimize potential risks to public health. In this brief article we provide an overview of the molecular mechanisms of antimicrobial resistance in genes found in finfish aquaculture environments and highlight specific research that should provide the basis of sound, science-based policies for the use of antimicrobials in aquaculture.Frontiers in Microbiology 08/2013; 4:233. DOI:10.3389/fmicb.2013.00233 · 3.94 Impact Factor