RESUMO
Tetracyclines are important antimicrobial drugs for poultry farming that are actively excreted via feces and urine. Droppings are one of the main components in broiler bedding, which is commonly used as an organic fertilizer. Therefore, bedding becomes an unintended carrier of antimicrobial residues into the environment and may pose a highly significant threat to public health. For this depletion study, 60 broiler chickens were treated with 20% chlortetracycline (CTC) under therapeutic conditions. Concentrations of CTC and 4-epi-CTC were then determined in their droppings. Additionally, this work also aimed to detect the antimicrobial activity of these droppings and the phenotypic susceptibility to tetracycline in E. coli isolates, as well as the presence of tet(A), tet(B), and tet(G) resistance genes. CTC and 4-epi-CTC concentrations that were found ranged from 179.5 to 665.8 µg/kg. Based on these data, the depletion time for chicken droppings was calculated and set at 69 days. All samples presented antimicrobial activity, and a resistance to tetracyclines was found in bacterial strains that were isolated from these samples. Resistance genes tet(A) and tet(B) were also found in these samples.
Assuntos
Antibacterianos/isolamento & purificação , Antiporters/genética , Proteínas de Bactérias/genética , Clortetraciclina/isolamento & purificação , Resíduos de Drogas/isolamento & purificação , Infecções por Escherichia coli/veterinária , Doenças das Aves Domésticas/prevenção & controle , Animais , Animais Recém-Nascidos , Antibacterianos/farmacologia , Antiporters/metabolismo , Proteínas de Bactérias/metabolismo , Galinhas , Clortetraciclina/farmacologia , Resíduos de Drogas/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/prevenção & controle , Fezes/química , Expressão Gênica , Masculino , Testes de Sensibilidade Microbiana , Doenças das Aves Domésticas/microbiologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMO
The ability to avoid and escape from predators are clearly relevant behaviors from the ecological perspective and directly interfere with the survival of organisms. Detected in the aquatic environment, risperidone can alter the behavior of exposed species. Considering the risk of exposure in the early stages of life, we exposed zebrafish embryos to risperidone during the first 5 days of life. Risperidone caused hyperactivity in exposed larvae, which in an environmental context, the animals may be more vulnerable to predation due to greater visibility or less perception of risk areas.
Assuntos
Comportamento Animal/efeitos dos fármacos , Resíduos de Drogas/farmacologia , Larva/efeitos dos fármacos , Psicotrópicos/farmacologia , Risperidona/farmacologia , Poluentes Químicos da Água/farmacologia , Peixe-Zebra , Animais , Relação Dose-Resposta a DrogaRESUMO
Tetracyclines are used for the prevention and control of dairy cattle diseases. Residues of these drugs can be excreted into milk. Thus, the aim of this study was to develop a microbiological method using Bacillus megaterium to detect tetracyclines (chlortetracycline, oxytetracycline and tetracycline) in milk. In order to approximate the limits of detection of the bioassay to the Maximum Residue Limit (100µg/l) for milk tetracycline, different concentrations of chloramphenicol (0, 1000, 1500 and 2000µg/l) were tested. The detection limits calculated were similar to the Maximum Residue Limits when a bioassay using B. megaterium ATCC 9885 spores (2.8×10(8)spores/ml) and chloramphenicol (2000µg/l) was utilized. This bioassay detects 105µg/l of chlortetracycline, 100µg/l of oxytetracycline and 134µg/l of tetracycline in 5h. Therefore, this method is suitable to be incorporated into a microbiological multi-residue system for the identification of tetracyclines in milk.
Assuntos
Antibacterianos/análise , Bacillus megaterium/efeitos dos fármacos , Bioensaio/métodos , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Leite/química , Tetraciclinas/análise , Animais , Antibacterianos/farmacologia , Argentina , Bacillus megaterium/fisiologia , Cloranfenicol/análise , Cloranfenicol/farmacologia , Resíduos de Drogas/farmacologia , Contaminação de Alimentos/legislação & jurisprudência , Concentração Máxima Permitida , Sensibilidade e Especificidade , Esporos Bacterianos/efeitos dos fármacos , Tetraciclinas/farmacologiaRESUMO
The establishment of the impact of environmental compounds or additives with hormone-like activity on human health still requires further investigation, as well as a reexamination of biologic models and experimental methodology employed so far. In 1988, the FAO/WHO Expert Committee on Food Additives Joint with the Federal Drug Administration (FDA) considered that sexual hormone residues usually present in meat do not represent a risk for human consumption. Nevertheless, this resolution seems to be uncertain since the scientific elements employed for this statement may not be adequate. In this review the principal objections to the evidence used to establish the innocuousness of growth promoter hormones are considered.