RESUMO
The microbiological quality of oysters reflects the microbiological quality of their habitats because they are filter feeders. The objective of this study was to assess the bacterial composition of the edible oyster Crassostrea rhizophorae in urban and preserved estuaries. Particularly, we assessed the presence of pathogenic bacteria, investigated antibiotic susceptibility in bacterial isolates, and quantified ß-lactam antibiotic resistance genes (blaTEM, blaSHV, and blaKPC) via quantitative PCR of oyster DNA. Our results detected total coliforms, Escherichia coli , and enterobacteria in the oysters from urban estuaries, which is indicative of poor water quality. In addition, our detection of the eaeA and stxA2 virulence genes in 16.7% of E. coli isolates from oysters from this region suggests the presence of multiantibiotic-resistant enteropathogenic and enterohemorrhagic E. coli strains. During periods of low precipitation, increased contamination by E. coli (in winter) and Vibrio parahaemolyticus (in autumn) was observed. In contrast, cultivated oysters inhabiting monitored farms in preserved areas had low levels of bacterial contamination, emphasizing that oyster culture monitoring enhances food quality and makes oysters fit for human consumption. Distinct antibiotic resistance profiles were observed in bacteria isolated from oysters collected from different areas, including resistance to ß-lactam antibiotics. The presence of the blaTEM gene in 91.3% of oyster samples indicated that microorganisms in estuarine water conferred the capability to produce ß-lactamase. To our knowledge, this is the first study to directly quantify and detect ß-lactam antibiotic resistance genes in oysters. We believe our study provides baseline data for bacterial dynamics in estuarine oysters; such knowledge contributes to developing risk assessments to determine the associated hazards and consequences of consuming oysters from aquatic environments containing pathogenic bacteria that may possess antibiotic resistance genes.
Assuntos
Crassostrea/microbiologia , beta-Lactamas , Animais , Escherichia coli/isolamento & purificação , Humanos , Prevalência , beta-LactamasesRESUMO
O objetivo deste trabalho foi analisar a qualidade microbiológica de 40 amostras de matérias-primas de fitoterápicos coletadas de farmácias de manipulação da região central Rio Grande do Sul. Foram realizados os testes de contagem de microrganismos viáveis e pesquisa e identificação de patógenos, ambos de acordo com a Farmacopéia Brasileira. Os resultados obtidos mostraram que há presença de microrganismos nas amostras, entretanto, em nenhuma delas, o valor de UFC g-1 ultrapassou o limite estabelecido para fitoterápicos na Farmacopéia Britânica, tanto para bactérias como para fungos. No teste de pesquisa e identificação de patógenos comprovou-se que não havia a presença de Pseudomonas aeruginosa, Salmonella sp, Staphylococcus aureus e Escherichia coli, nas amostras analisadas. As amostras estão aptas a serem comercializadas, pois todas estavam dentro dos limites especificados, e foram aprovadas pelo teste de controle de qualidade microbiológico.
The aim of this study was to analyze the microbiological quality of 40 samples of raw material for herbal medicines collected from compounding pharmacies in the center of Rio Grande do Sul, Brazil. Count of viable microorganisms and search and identification of pathogens were performed, both according to the Brazilian Pharmacopoeia. Results showed that there were microorganisms in the samples; however, in none of them, the value of CFU g-1 was above the limit established for herbal medicines by the British Pharmacopoeia, both for bacteria and fungi. The search and identification of pathogens indicated that there was no Pseudomonas aeruginosa, Salmonella sp, Staphylococcus aureus and Escherichia coli in the analyzed samples. The samples can be commercialized because all of them were within the allowed limits and were approved in the test for microbiological quality control.