ABSTRACT
Campylobacter spp. is an emerging pathogen that causes gastroenteritis in humans and the consumption of dairy food can characterize sources of infection. We aimed to verify the viability and a presence of transcripts associated with characteristics of virulence and adaptation of C. jejuni isolated from Minas Frescal cheeses, produced with contaminated milk and stored under refrigeration for up to ten days. The samples were analyzed for bioindicators, Campylobacter spp., pH, acidity, moisture and sodium chloride. Campylobacter spp. recovered were evaluated for the production of transcripts of: ciaB, dnaJ, p19 and sodB. The results were correlated with the viability of C. jejuni and changes in their transcriptome. Storage at lowtemperatures reduced C. jejuni from the first to the fourth day. The variations in humidity, pH and acidity influenced the decreasing of C. jejuni. There was a reduction in transcripts' production of the four genes, more pronounced on the fourth day, indicating the inability of the microorganism to perform its metabolic activities, due to the conditions of injury. Despite the presence of mechanisms of virulence and adaptation, C. jejuni could not remain viable four days after production. However, consumption of fresh cheese contaminated with Campylobacter jejuni can be a source of infection when consumed up to four days after production.
Campylobacter spp. é um patógeno emergente que causa gastroenterite em seres humanos e o consumo de produtos lácteos pode caracterizar fontes de infecção. O objetivo deste estudo foi verificar a viabilidade e a presença de transcritos associadas a características de virulência e adaptação de C. jejuniisoladas de queijos frescos, produzidos com leite contaminado e mantidos refrigeradas por dez dias. Foram analisados bioindicadores, Campylobacter spp., pH, acidez, umidade e cloreto de sódio. Campylobacter spp. recuperados foram avaliados quanto à produção dos transcritos: ciaB, dnaJ, p19 e sodB. Os resultados foram correlacionados com a viabilidade de C. jejuni e alterações no transcriptoma. O armazenamento em baixas temperaturas reduziu C. jejuni do primeiro ao quarto dia. As variações na umidade, pH e acidez influenciaram a queda de C. jejuni. Houve uma redução na produção de transcritos dos quatro genes, mais pronunciada no quarto dia, indicando a incapacidade do micro-organismo em realizar suas atividades metabólicas, devido às condições de injúria. Apesar da presença de mecanismos de virulência e adaptação, C. jejuni não permaneceu viável quatro dias após a produção. Porém, o consumo de queijo fresco contaminado com Campylobacter jejunipode ser uma fonte de infecção quando consumido até quatro dias após a produção.
Subject(s)
Campylobacter Infections , Cheese , Campylobacter jejuni , Virulence , Dairy Products , Gastroenteritis , Infections , NoxaeABSTRACT
Campylobacter é o agente etiológico mais prevalente em gastroenterites de causa alimentar no mundo. Apesar de o leite cru ser fonte de infecção, pouco se conhece sobre as consequências da recontaminação do leite. A viabilidade de Campylobacter jejuni foi avaliada em leites pasteurizados e UHT mantidos sob refrigeração. Ambos os leites foram divididos em cinco porções de 100 mL, inoculados com 101 UFC.mL-1 de C. jejuni e mantidos de 4 ºC a 7 ºC por 48 horas. Repetiu-se o procedimento, utilizando-se inoculações de 102, 103 e 104 UFC.mL-1. As alíquotas foram analisadas imediatamente após inoculação e depois de 24 e 48 h quanto à viabilidade de C. jejuni. O micro-organismo manteve-se viável em todas as amostras, porém no leite pasteurizado houve redução de 1 ciclo log nas contagens após 24 h e baixas contagens após 48 h. Provavelmente,a redução ocorreu pela presença de microbiota neste leite, que competiu ou inibiu o crescimento de C. jejuni. O leite UHT ofereceu boas condições de sobrevivência em todos os períodos. O consumo de leite contaminado, mesmo em armazenamento refrigerado, pode ser fonte de infecção. O micro-organismo manteve-se mais viável no leite UHT quando comparado ao pasteurizado, provavelmente pela ausência de outros micro-organismos competidores.
Campylobacter is the most prevalent etiologic agent of foodborne gastroenteritis worldwide.Although raw milk is an important source of infection, little is known about the consequencesof milk recontamination. This study aimed at verifying the viability of Campylobacter jejuni inpasteurized and UHT milks stored under refrigeration. Both samples were divided into five portionsof 100 mL, inoculated with 101 CFU.mL-1 of C. jejuni and stored at 4 °C - 7 ºC for 48 h. The procedure was repeated using inoculations of 102, 103 and 104 CFU.mL-1. Aliquots were analyzed immediatelyafter inoculation and after 24 and 48 h to evaluate C. jejuni viability. The microorganism their viabilityin all of samples. In pasteurized milk a reduction of 1 log cycle occurred after 24 h and low countsafter 48 h. Probably, the reduction happened due to the occurrence of microbiota in this milk, whichcaused competition or inhibition of microorganism growth. UHT milk offered good conditions forbacteria survival in all of the periods. The consumption of contaminated milk, even stored under refrigeration might be a source of infection. Microorganism were more viable in UHT milk thanin pasteurized one, probably owing to the absence of competing microorganisms.
Subject(s)
Cooled Foods , Campylobacter jejuni , Food Contamination , Gastroenteritis , MilkABSTRACT
This study evaluated the ability of Campylobacter jejuni to penetrate through the pores of the shells of commercial eggs and colonize the interior of these eggs, which may become a risk factor for human infection. Furthermore, this study assessed the survival and viability of the bacteria in commercial eggs. The eggs were placed in contact with wood shavings infected with C. jejuni to check the passage of the bacteria. In parallel, the bacteria were inoculated directly into the air chamber to assess the viability in the egg yolk. To determine whether the albumen and egg fertility interferes with the entry and survival of bacteria, we used varying concentrations of albumen and SPF and commercial eggs. C. jejuni was recovered in SPF eggs (fertile) after three hours in contact with contaminated wood shavings but not in infertile commercial eggs. The colonies isolated in the SPF eggs were identified by multiplex PCR and the similarity between strains verified by RAPD-PCR. The bacteria grew in different concentrations of albumen in commercial and SPF eggs. We did not find C. jejuni in commercial eggs inoculated directly into the air chamber, but the bacteria were viable during all periods tested in the wood shavings. This study shows that consumption of commercial eggs infected with C. jejuni does not represent a potential risk to human health.
Subject(s)
Humans , Animals , Campylobacter jejuni/isolation & purification , Campylobacter jejuni/physiology , Eggs/microbiology , Microbial ViabilityABSTRACT
A habilidade do gênero Salmonella em causar doenças depende de vários fatores genéticos determinantes, dentre eles destacam-se os genes que codificam alguma característica de virulência nessas bactérias. Objetivou-se com esse trabalho pesquisar genes associados à virulência em isolados de Salmonella spp. de origem avícola, em sua fase de aderência e invasão celular, e avaliar a resistência desses isolados a 11 antimicrobianos. Foram analisadas 18 amostras de Salmonella spp. isoladas durante o ano de 2009 a partir de suabes de arrasto provenientes de aviários de frango de corte do estado de São Paulo. Todas as amostras foram testadas através da técnica de PCR para os genes associados à virulência: invA, lpfA e agfA. A maioria das amostras apresentou alta positividade para os genes de virulência, e 88,9% das amostras apresentaram os três genes estudados. Verificou-se que 17 amostras (94,4%) apresentaram fragmentos específicos para os genes invA e lpfA e o gene agfA foi positivo em todas as amostras avaliadas (100%). Todas as cepas apresentaram resistência pelo menos a um antimicrobiano testado. Os dados indicaram que das amostras analisadas a maior resistência foi à amoxacilina com 27,7%. Os resultados demonstram a patogenicidade dos sorovares de Salmonella, que representam potenciais desafios sanitários na avicultura, pelo risco da disseminação de espécimes virulentos e multirresistentes entre os animais e que, consequentemente, podem acometer o homem.
The ability of Salmonella to cause disease depends on several genetic determinant factors, including genes that encodes some virulence trait of these bacteria. The aim of this work was to research genes associated with virulence in Salmonella isolates of poultry products in its phase of adhesion and cell invasion, and to evaluate the resistance of these isolates to 11 antimicrobials. Were analyzed 18 samples of Salmonella spp. isolated during the 2009 year using drag swabs from poultry broiler in the state of São Paulo. All samples were tested using PCR technique for genes that were associated to virulence: invA, lpfA and agfA. Most samples had high positivity to virulence genes, and 88.9% of the samples had the three genes. It was verified that 17 samples (94.4%) had specific fragments to the invA and lpfA genes and the gene agfA was positive in all samples (100%). All samples were resistant to at least one antibiotic tested, the data indicated that the samples analyzed had greatest resistance to amoxacilin with 27.7%. The results demonstrate the pathogenicity of the Salmonella serovars which represent potential health challenges in poultry, the risk of the spread of multidrug resistant and virulent specimens among the animals and therefore can affect humans.