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1.
BMC Infect Dis ; 20(1): 83, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996135

RESUMO

BACKGROUND: The more quickly bacterial pathogens responsible for foodborne illness outbreaks can be linked to a vehicle of transmission or a source, the more illnesses can be prevented. Whole genome sequencing (WGS) based approaches to source tracking have greatly increased the speed and resolution with which public health response can pinpoint the vehicle and source of outbreaks. Traditionally, WGS approaches have focused on the culture of an individual isolate before proceeding to DNA extraction and sequencing. For Listeria monocytogenes (Lm), generation of an individual isolate for sequencing typically takes about 6 days. Here we demonstrate that a hybrid, "quasimetagenomic" approach ie; direct sequencing of microbiological enrichments (first step in pathogen detection and recovery) can provide high resolution source tracking sequence data, 5 days earlier than response that focuses on culture and sequencing of an individual isolate. This expedited approach could save lives, prevent illnesses and potentially minimize unnecessary destruction of food. METHODS: Naturally contaminated ice cream (from a 2015 outbreak) was enriched to recover Listeria monocytogenes following protocols outlined in the Bacteriological Analytic Manual (BAM). DNA from enriching microbiota was extracted and sequenced at incremental time-points during the first 48 h of pre-enrichment using the Illumina MiSeq platform (2 by 250), to evaluate genomic coverage of target pathogen, Listeria monocytogenes. RESULTS: Quasimetagenomic sequence data acquired from hour 20 were sufficient to discern whether or not Lm strain/s were part of the ongoing outbreak or not. Genomic data from hours 24, 28, 32, 36, 40, 44, and 48 of pre-enrichments all provided identical phylogenetic source tracking utility to the WGS of individual isolates (which require an additional 5 days to culture). CONCLUSIONS: The speed of this approach (more than twice as fast as current methods) has the potential to reduce the number of illnesses associated with any given outbreak by as many as 75% percent of total cases and potentially with continued optimization of the entire chain of response, contribute to minimized food waste.


Assuntos
Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Sorvetes/microbiologia , Listeria monocytogenes/genética , Listeriose/microbiologia , Metagenômica , Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Humanos , Listeria monocytogenes/classificação , Listeriose/epidemiologia , Filogenia , Fatores de Tempo , Sequenciamento Completo do Genoma
2.
Food Microbiol ; 85: 103280, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500706

RESUMO

Listeria monocytogenes causes severe diseases in humans, including febrile gastroenteritis and systemic infections that has a high mortality despite antibiotic treatment. This pathogen may cause massive outbreaks associated to the consumption of contaminated food products, which highlight its importance in public health. In the last decade, L. monocytogenes has emerged as a foodborne pathogen of major importance in Chile. A previous work showed that in Chile during 2008 and 2009, L. monocytogenes serotypes 1/2a, 1/2b and 4b were the most frequently identified in food and clinical strains. Here we report the molecular characterization of L. monocytogenes strains isolated from 2008 to 2017 in the country. Our results indicate that serotypes 1/2a, 1/2b and 4b continue to be the most commonly found in food products. In addition, we identify persistent and widespread PFGE subtypes. This study reports ten years of epidemiological surveillance ofL. monocytogenes in Chile.


Assuntos
Monitoramento Epidemiológico , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Listeria monocytogenes/genética , Listeriose/epidemiologia , Chile/epidemiologia , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Surtos de Doenças , Doenças Transmitidas por Alimentos/microbiologia , Gastroenterite/epidemiologia , Gastroenterite/microbiologia , Variação Genética , Humanos , Listeria monocytogenes/patogenicidade , Produtos da Carne/microbiologia , Epidemiologia Molecular , Saúde Pública , Sorogrupo , Sorotipagem , Fatores de Virulência/genética
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117386, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31336320

RESUMO

Non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups such as O26, O45, O103, O111, O121 and O145 often cause illness to people in the United States and the conventional identification of these "Big-Six" are complex. The label-free hyperspectral microscope imaging (HMI) method, which provides spectral "fingerprints" information of bacterial cells, was employed to classify serogroups at the cellular level. In spectral analysis, principal component analysis (PCA) method and stacked auto-encoder (SAE) method were conducted to extract principal spectral features for classification task. Based on these features, multiple classifiers including linear discriminant analysis (LDA), support vector machine (SVM) and soft-max regression (SR) methods were evaluated. Different sizes of datasets were also tested in search for the suitable classification models. Among the results, SAE-based classification models performed better than PCA-based models, achieving classification accuracy of SAE-LDA (93.5%), SAE-SVM (94.9%) and SAE-SR (94.6%), respectively. In contrast, classification results of PCA-based methods such as PCA-LDA, PCA-SVM and PCA-SR were only 75.5%, 85.7% and 77.1%, respectively. The results also suggested the increasing number of training samples have positive effects on classification models. Taking advantage of increasing dataset, the SAE-SR classification model finally performed better than others with average accuracy of 94.9% in classifying STEC serogroups. Specifically, O103 serogroup was classified with the highest accuracy of 97.4%, followed by O111 (96.5%), O26 (95.3%), O121 (95%), O145 (92.9%) and O45 (92.4%), respectively. Thus, the HMI technology coupled with SAE-SR classification model has the potential for "Big-Six" identification.


Assuntos
Técnicas de Tipagem Bacteriana/métodos , Aprendizado Profundo , Processamento de Imagem Assistida por Computador/métodos , Microscopia/métodos , Escherichia coli Shiga Toxigênica , Algoritmos , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Imagem Óptica/métodos , Análise de Componente Principal , Escherichia coli Shiga Toxigênica/química , Escherichia coli Shiga Toxigênica/classificação
4.
BMC Infect Dis ; 19(1): 1066, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31856747

RESUMO

BACKGROUND: Symptomatic and asymptomatic enteric infections in early childhood are associated with negative effects on childhood growth and development, especially in low and middle-income countries, and food may be an important transmission route. Although basic food hygiene practices might reduce exposure to faecal pathogens and resulting infections, there have been few rigorous interventions studies to assess this, and no studies in low income urban settings where risks are plausibly very high. The aim of this study is to evaluate the impact of a novel infant food hygiene intervention on infant enteric infections and diarrhoea in peri-urban settlements of Kisumu, Kenya. METHODS: This is a cluster randomized control trial with 50 clusters, representing the catchment areas of Community Health Volunteers (CHVs), randomly assigned to intervention or control, and a total of 750 infants recruited on a rolling basis at 22 weeks of age and then followed for 15 weeks. The intervention targeted four key caregiver behaviours related to food hygiene: 1) hand washing with soap before infant food preparation and feeding; 2) bringing all infant food to the boil before feeding, including when reheating or reserving; 3) storing all infant food in sealed containers; and, 4) using only specific utensils for infant feeding which are kept separate and clean. RESULTS: The primary outcome of interest is the prevalence of one or more of 23 pre-specified enteric infections, determined using quantitative real-time polymerase chain reaction for enteric pathogen gene targets. In addition, infant food samples were collected at 33 weeks, and faecal indicator bacteria (Enterococcus) isolated and enumerated to assess the impact of the intervention on infant food contamination. CONCLUSION: To our knowledge this is the first randomized controlled trial to assess the effect of an infant food hygiene intervention on enteric infections in a high burden, low income urban setting. Our trial responds to growing evidence that food may be a key pathway for early childhood enteric infection and disease and that basic food hygiene behaviours may be able to mitigate these risks. The Safe Start trial seeks to provide new evidence as to whether a locally appropriate infant food hygiene intervention delivered through the local health extension system can improve the health of young children. TRIAL REGISTRATION: The trial was registered at clinicaltrial.gov on March 16th 2018 before enrolment of any participants (https://clinicaltrials.gov/ct2/show/NCT03468114).


Assuntos
Diarreia/epidemiologia , Diarreia/microbiologia , Enterite/epidemiologia , Enterite/microbiologia , Desinfecção das Mãos/métodos , Pobreza , Cuidadores , Culinária , Diarreia/prevenção & controle , Enterite/prevenção & controle , Enterococcus/isolamento & purificação , Fezes/microbiologia , Feminino , Contaminação de Alimentos/prevenção & controle , Armazenamento de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Lactente , Controle de Infecções , Quênia/epidemiologia , Masculino , Saúde Pública , Sabões , Saúde da População Urbana
5.
Ann Agric Environ Med ; 26(4): 532-537, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31885224

RESUMO

Infections caused by extra-intestinal pathogenic Escherichia coli (ExPEC) are a serious public health problem worldwide. The most troublesome are urinary tract infections, severe neonatal meningitis, serious intraabdominal infections, and more rarely, pneumonia, intravascular-device infections, osteomyelitis, soft-tissue infections or sometimes bacteraemia. These strains are also able cause significant economic losses in animal husbandry. A thorough understanding of ExPEC ecology, reservoirs, chains and dynamics of transmission can greatly contribute to a reduction in the burden of ExPEC-associated disease. The ability of E. coli (including ExPEC) to exist and survive in various ecological niches impedes the precise recognition and indication of transmission routes most important for individual infections cases. Among many identified ExPEC reservoirs, animal companion and animals providing food seem to be important sources of infection for human; however, the real level of risk connected with potential transmission of these bacteria remains unclear. Food is indicated as one of potential ways of transmission. Despite a quite high number of reports, many of the uncertainties are expected to be reliably elucidated. This review presents most important data on the current state of knowledge concerning the potential role of food in ExPEC transmission. The possible consequences of ExPEC infections in human and animals are briefly described.


Assuntos
Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/fisiologia , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/veterinária , Animais , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/transmissão , Contaminação de Alimentos/análise , Humanos
6.
N Engl J Med ; 381(26): 2569-2580, 2019 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-31881145

RESUMO

Rapid advances in DNA sequencing technology ("next-generation sequencing") have inspired optimism about the potential of human genomics for "precision medicine." Meanwhile, pathogen genomics is already delivering "precision public health" through more effective investigations of outbreaks of foodborne illnesses, better-targeted tuberculosis control, and more timely and granular influenza surveillance to inform the selection of vaccine strains. In this article, we describe how public health agencies have been adopting pathogen genomics to improve their effectiveness in almost all domains of infectious disease. This momentum is likely to continue, given the ongoing development in sequencing and sequencing-related technologies.


Assuntos
Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Influenza Humana/epidemiologia , Saúde Pública , Tuberculose/epidemiologia , Animais , Bactérias/genética , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/parasitologia , Humanos , Influenza Humana/diagnóstico , Influenza Humana/microbiologia , Metagenômica , Parasitos/genética , Tuberculose/diagnóstico , Vírus/genética
7.
BMC Infect Dis ; 19(1): 910, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664944

RESUMO

BACKGROUND: On September 4, 2018, a boarding school in the Shunyi District of Beijing, China reported an outbreak of acute gastroenteritis. At least 209 suspected students caused of diarrhea and vomiting. The case was investigated, and control measures were taken to prevent further spread. METHODS: A retrospective cohort study was conducted among the school students and staff in order to test hypothesis that high risk of food served at the school canteen. We collected information on demographics, refectory records, person to person transmission by uniform epidemiological questionnaire. Risk ratios (RR) and 95% confidence intervals (CI) were calculated. Stool specimens of cases and canteen employees, retained food, water, and environmental swabs were investigated by laboratory analysis. RESULTS: We identified 209 cases (including 28 laboratory-confirmed cases) which occurred from August 29 to September 10. All cases were students, and the average age was 20, 52% were male. The outbreak lasted for 13 days, and peaked on September 5. Consumption of Drinks stall and Rice flour stall on September 1 (RR:3.4, 95%CI:1.5-7.8, and RR:7.6, 95%CI:2.8-20.2), Rice flour stall and Fish meal stall on September 2 (RR:4.0, 95%CI:1.2-13.6, and RR:4.6, 95%CI:1.7-12.5), muslim meal stall on September 4 (RR:2.7, 95%CI:1.3-5.4), Barbeque stall on September 5 (RR:3.0, 95%CI:1.2-7.0) were independently associated with increased risk of disease within the following 2 days. Among 35 specimens of rectal swabs or feces from students, 28 specimens were positive. Norovirus GI.6 alone was detected in 23 specimens, Bacillus cereus alone in 3 specimens and both norovirus GI.6 and Bacillus cereus in 2 specimens. Ten specimens of rectal swabs from canteen employees were positive for norovirus GI, and 2 specimens were positive for Bacillus cereus. Four retained food specimens were positive for Bacillus cereus, and environmental samples were negative for any viruses or bacteria. CONCLUSION: Our investigation indicated that canteen employees were infected by two pathogens (norovirus and Bacillus cereus) and transmission may have been possible due to unhygienic practices. Student consumption of food or drink at high-risk stalls was determined as the probable cause of the outbreak.


Assuntos
Bacillus cereus/isolamento & purificação , Infecções por Caliciviridae/epidemiologia , Surtos de Doenças , Doenças Transmitidas por Alimentos/microbiologia , Gastroenterite/epidemiologia , Norovirus/isolamento & purificação , Adolescente , Pequim/epidemiologia , Infecções por Caliciviridae/complicações , Diarreia/complicações , Fezes/microbiologia , Fezes/virologia , Feminino , Contaminação de Alimentos , Doenças Transmitidas por Alimentos/virologia , Gastroenterite/complicações , Higiene das Mãos , Humanos , Masculino , Razão de Chances , Estudos Retrospectivos , Inquéritos e Questionários , Universidades , Vômito/complicações , Adulto Jovem
8.
Infect Immun ; 87(12)2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31570559

RESUMO

Campylobacter jejuni is a leading cause of foodborne illnesses worldwide. Its porA gene encodes the major outer membrane protein (MOMP) that is abundantly expressed and has important physiological functions, including a key role in systemic infection and abortion induction in pregnant animals. Despite the importance of porA in C. jejuni pathogenesis, mechanisms modulating its expression levels remain elusive. At the 3' end of the porA transcript, there is a Rho-independent transcription terminator (named T porA in this study). Whether T porA affects the expression and function of MOMP remains unknown and is investigated in this study. Green fluorescent protein (GFP) fusion constructs with the porA promoter at the 5' end and an intact T porA or no T porA at the 3' end of the gfp coding sequence revealed that both the transcript level of gfp and its fluorescence signals were more than 2-fold higher in the construct with T porA than in the one without T porA Real-time quantitative PCR (qRT-PCR) analysis of the porA mRNA and immunoblot detection of MOMP in C. jejuni showed that disruption of T porA significantly reduced the porA transcript level and the expression of MOMP. An mRNA decay assay demonstrated that disruption of T porA resulted in a shortened transcript half-life of the upstream gfp or porA gene, indicating that T porA enhances mRNA stability. In the guinea pig model, the C. jejuni construct with an interrupted T porA was significantly attenuated in abortion induction. Together, these results indicate that T porA enhances the expression level of MOMP by stabilizing its mRNA and influences the virulence of C. jejuni.


Assuntos
Aborto Animal/genética , Proteínas de Bactérias/genética , Infecções por Campylobacter/patologia , Campylobacter jejuni/patogenicidade , Porinas/genética , Aborto Animal/microbiologia , Animais , Proteínas de Bactérias/biossíntese , Infecções por Campylobacter/imunologia , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/imunologia , Feminino , Doenças Transmitidas por Alimentos/microbiologia , Cobaias , Porinas/biossíntese , Gravidez , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , Terminação da Transcrição Genética , Virulência/genética
9.
Pak J Pharm Sci ; 32(4): 1485-1494, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31608866

RESUMO

This study sheds the light on the presence of (some) food-borne pathogens in raw market milk in Mansoura city, (Egypt) using several techniques for isolation and identification including serology and PCR. It determines, further, the susceptibility of the isolated pathogens to some antimicrobial agents and natural oils, including watercress, basil, parsley, and hot green pepper oils. From 100 milk samples, 22 Escherichia coli isolates harboured stx1, stx2 and/or eae genes. Additionally, 17 Listeria monocytogenes (L. monocytogenes) isolates harboured hylA gene. Moreover, other related pathogens such as Shigella flexneri and Klebsiella pneumoniae were also detected. Antimicrobial susceptibility testing showed that E. coli strains were (completely) resistant to amoxicillin and sulfamethoxazole-trimethoprim but highly sensitive to gentamicin. L. monocytogenes strains showed complete resistance against oxytetracycline while the highest percentage of sensitivity was observed against norfloxacin. This study has also proved the following: L. monocytogenes was susceptible to all of the investigated oils, Klebsiella pneumoniae was sensitive to two types of oils, but E. coli and Shigella flexneri were resistant to all oils. In conclusion, it is risky to consume unpasteurized milk. Further, some natural oils (e.g. parsley and hot green pepper oils) can successfully be used as food additives to control the presence of some pathogens in milk.


Assuntos
Antibacterianos/farmacologia , Microbiologia de Alimentos , Leite/microbiologia , Óleos Vegetais/farmacologia , Adesinas Bacterianas/genética , Animais , Farmacorresistência Bacteriana/efeitos dos fármacos , Egito , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Proteínas de Escherichia coli/genética , Doenças Transmitidas por Alimentos/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Testes de Sensibilidade Microbiana , Toxina Shiga I/genética , Toxina Shiga II/genética , Shigella flexneri/efeitos dos fármacos
10.
Pediatrics ; 144(4)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31519792

RESUMO

BACKGROUND: In 2017, we conducted a multistate investigation to determine the source of an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections, which occurred primarily in children. METHODS: We defined a case as infection with an outbreak strain of STEC O157:H7 with illness onset between January 1, 2017, and April 30, 2017. Case patients were interviewed to identify common exposures. Traceback and facility investigations were conducted; food samples were tested for STEC. RESULTS: We identified 32 cases from 12 states. Twenty-six (81%) cases occurred in children <18 years old; 8 children developed hemolytic uremic syndrome. Twenty-five (78%) case patients ate the same brand of soy nut butter or attended facilities that served it. We identified 3 illness subclusters, including a child care center where person-to-person transmission may have occurred. Testing isolated an outbreak strain from 11 soy nut butter samples. Investigations identified violations of good manufacturing practices at the soy nut butter manufacturing facility with opportunities for product contamination, although the specific route of contamination was undetermined. CONCLUSIONS: This investigation identified soy nut butter as the source of a multistate outbreak of STEC infections affecting mainly children. The ensuing recall of all soy nut butter products the facility manufactured, totaling >1.2 million lb, likely prevented additional illnesses. Prompt diagnosis of STEC infections and appropriate specimen collection aids in outbreak detection. Child care providers should follow appropriate hygiene practices to prevent secondary spread of enteric illness in child care settings. Firms should manufacture ready-to-eat foods in a manner that minimizes the risk of contamination.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157 , Doenças Transmitidas por Alimentos/epidemiologia , Escherichia coli Shiga Toxigênica , Alimentos de Soja/microbiologia , Adolescente , Idoso , Criança , Creches/estatística & dados numéricos , Pré-Escolar , Infecções por Escherichia coli/microbiologia , Fast Foods/efeitos adversos , Fast Foods/microbiologia , Feminino , Manipulação de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Síndrome Hemolítico-Urêmica/microbiologia , Humanos , Lactente , Masculino , Recall e Retirada de Produto , Alimentos de Soja/efeitos adversos , Estados Unidos/epidemiologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-31522662

RESUMO

A cluster of gastrointestinal illness was detected following receipt of a complaint of becoming ill after a multi-course dinner at a restaurant in Canberra, Australian Capital Territory (ACT), Australia. The complaint led to an investigation by ACT Health. Food samples retained by the restaurant for microbiological analysis returned an unsatisfactory level of Bacillus cereus in beef (19,000 colony forming units/gram [cfu/g]) and a satisfactory level in arancini (50 cfu/g). These positive samples underwent whole genome sequencing and genes encoding diarrhoeal toxins were detected with no laboratory evidence of the emetic toxin. No stool specimens were collected. A cohort study was undertaken and 80% (33/41) of patrons took part in a structured interview. There was no significant difference in age or sex between those ill and not ill. Due to universal exposure most foods were unable to be statistically analysed and no significant results were found from the food history. The ill cohort diverged into two distinct groups based on incubation period and symptoms suggesting this outbreak involved B. cereus intoxication with both diarrhoeal and potentially emetic toxins. Some hygiene practices during food preparation were noted to be inadequate and heating and cooling procedures were unverified when questioned. A combination of the incubation periods and symptom profile, food laboratory evidence, and genomic sequencing of the B. cereus diarrhoeal gene suggest a probable aetiology of B. cereus intoxication. Public health action included the restaurant rectifying hygiene practices and documenting heating/cooling procedures.


Assuntos
Bacillus cereus/isolamento & purificação , Toxinas Bacterianas/toxicidade , Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Gastroenterite/epidemiologia , Carne Vermelha/microbiologia , Animais , Território da Capital Australiana/epidemiologia , Bacillus cereus/genética , Bovinos , Estudos de Coortes , Diarreia/epidemiologia , Diarreia/microbiologia , Diarreia/mortalidade , Eméticos , Feminino , Contaminação de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/mortalidade , Gastroenterite/microbiologia , Gastroenterite/mortalidade , Humanos , Masculino , Restaurantes , Estudos Retrospectivos , Inquéritos e Questionários
12.
J Microbiol Biotechnol ; 29(10): 1543-1552, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31546299

RESUMO

Salmonella is a common zoonotic and foodborne pathogen that causes high morbidity and mortality in developing countries. In this study, we established and validated a polymerase spiral reaction (PSR) assay which targeted the conserved invasion gene (invA) of Salmonella by SYBR Green I indicator methods. Subsequently, assays for determination of the optimal conditions for optimal specificity and sensitivity of PSR were performed. We performed comprehensive evaluations using loop-mediated isothermal amplification (LAMP) and realtime PCR. A total number of 532 samples of daily food were analyzed by PSR. Twenty-seven bacterial strains were tested in the specificity assay, from which positive results were obtained only for 14-Salmonella strains. However, none of the 13 non-Salmonella strains was amplified. Similarly with LAMP and real-time PCR, the detection limit of the PSR assay was 50 CFU/ml. The PSR method was also successfully applied to evaluate the contamination with Salmonella in 532 samples of daily food, corroborating traditional culture method data. The novel PSR method is simple, sensitive, and rapid and provides new insights into the prevention and detection of foodborne diseases.


Assuntos
Microbiologia de Alimentos/métodos , Técnicas de Amplificação de Ácido Nucleico , Salmonella/isolamento & purificação , Proteínas de Bactérias/genética , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Limite de Detecção , Reprodutibilidade dos Testes , Salmonella/genética , Especificidade da Espécie , Fatores de Tempo
13.
World J Microbiol Biotechnol ; 35(9): 146, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31493271

RESUMO

The Campylobacter and Arcobacter genera encompass closely related species that are ubiquitous in nature and are harboured in the gastrointestinal tract of many animals, including food-producing animals (cattle, sheep, pigs and poultry). In humans Campylobacter spp. is the cause of most of the gastroenteritis cases worldwide and in more severe cases the infection can result in Guillian Barré syndrome. Similarly, Arcobacter species can cause gastroenteritis as well as bacteraemia. Infections in humans can be induced by the consumption of contaminated vegetables, meat, milk and water. However, food originating from animals, especially meat, has been recognised as a source of infection, in fact, poultry meat and meat products have been globally reported as the main source of infection. It is clear that food-producing animals are important reservoirs for Campylobacter and Arcobacter species, which implies successful colonisation of the gastrointestinal tract at primary production and contamination during the slaughter process. During slaughter the evisceration step has been recognised as the most likely point of contamination, as accidental spillage of intestinal fluid and rapture of gastrointestinal tract can occur. Therefore, improper hygienic practices can ultimately allow for the contamination of finished/retail products intended for human consumption. This literature review will seek to explore the infection of food-producing animals with Campylobacter and Arcobacter species at primary production and contamination during the slaughter of food-producing animals.


Assuntos
Arcobacter , Campylobacter , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Animais , Arcobacter/isolamento & purificação , Arcobacter/patogenicidade , Campylobacter/isolamento & purificação , Campylobacter/patogenicidade , Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/transmissão , Bovinos , Desinfecção , Manipulação de Alimentos , Trato Gastrointestinal/microbiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/transmissão , Humanos , Carne/microbiologia , Leite/microbiologia , Aves Domésticas , Prevalência , Ovinos , Pele , Suínos
14.
Int J Food Microbiol ; 309: 108327, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31493567

RESUMO

The apparent international rise in foodborne virus outbreaks attributed to fresh produce and the increasing importance of fresh produce in the Australian diet has led to the requirement to gather information to inform the development of risk management strategies. A prevalence survey for norovirus (NoV) and hepatitis A virus (HAV) in fresh Australian produce (leafy greens, strawberries and blueberries) at retail was undertaken during 2013-2014 and data used to develop a risk profile. The prevalence of HAV in berries and leafy greens was estimated to be <2%, with no virus detected in produce during the yearlong survey. The prevalence of NoV in fresh strawberries and blueberries was also estimated to be <2% with no virus detected in berries, whilst for leafy greens the NoV prevalence was 2.2%. Prevalence of a bacterial hygiene indicator, Escherichia coli, was also investigated and found to range from <1% in berries to 10.7% in leafy greens. None of the NoV positive leafy green samples tested positive for E. coli, indicating it is a poor indicator for viral risk. The risk was evaluated using standard codex procedures and the Risk Ranger tool. Taking all data into account, including the hazard dose and severity, probability of exposure, probability of infective dose and available epidemiological data, the risk of HAV and NoV foodborne illness associated with fresh Australian berries (strawberries and blueberries) sold as packaged product was deemed to be low. The risk of foodborne illness from HAV associated with leafy greens was also deemed to be low, but higher than that for fresh berries, due mainly to the potential for recontamination post-processing if sold loose. The risk of foodborne illness from NoV associated with leafy greens was deemed to be low/moderate. Despite the prevalence of NoV in leafy greens being low and the inability to discriminate between infective and non-infective virus using PCR based methodologies, the fact that NoV was detected resulted in a higher risk associated with this pathogen-product pairing; compounded by the higher prevalence of NoV within the community compared to HAV, and the potential for leafy greens to become contaminated following processing if sold loose.


Assuntos
Mirtilos Azuis (Planta)/microbiologia , Doenças Transmitidas por Alimentos/epidemiologia , Fragaria/microbiologia , Frutas/virologia , Vírus da Hepatite A/isolamento & purificação , Norovirus/isolamento & purificação , Austrália/epidemiologia , Surtos de Doenças , Escherichia coli/isolamento & purificação , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Folhas de Planta/microbiologia , Probabilidade
15.
Int J Food Microbiol ; 309: 108332, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31494483

RESUMO

Vibrio parahaemolyticus is a major food-borne pathogen. V. parahaemolyticus infections are associated with various serotypes; to date, 71 K-serogroups of V. parahaemolyticus have been determined based on capsular polysaccharide (CPS) diversity. In this study, the capsular polysaccharide gene clusters (CPSgcs) of 55 K-serogroups were identified by whole-genome sequencing and analysis. These CPSgcs exhibit a high level of genetic diversity. A microsphere-based suspension array (MSA) was established for the detection and identification of 55 V. parahaemolyticus K-serogroups based on CPSgc-specific genes. To evaluate our array, a double-blind test with 120 clinical isolates was carried out. In addition, an in silico K-serotyping system was established based on V. parahaemolyticus CPSgc-specific genes. This system was then used to examine 845 publicly available V. parahaemolyticus genomes; the results demonstrated that 813 isolates belong to one of 43 K-serogroups. Taken together, these results demonstrate that the molecular system developed in this study is suitable for rapid serotyping of V. parahaemolyticus isolates from environmental and clinical samples. In addition, the system could be applied to epidemiological investigations of this important food-borne pathogen.


Assuntos
Cápsulas Bacterianas/genética , Doenças Transmitidas por Alimentos/diagnóstico , Polissacarídeos Bacterianos/genética , Sorotipagem/métodos , Vibrio parahaemolyticus/genética , Vibrio parahaemolyticus/imunologia , Cápsulas Bacterianas/imunologia , Método Duplo-Cego , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Família Multigênica/genética , Polissacarídeos Bacterianos/imunologia , Sorogrupo , Vibrioses/diagnóstico , Vibrio parahaemolyticus/classificação
16.
BMC Res Notes ; 12(1): 516, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420003

RESUMO

OBJECTIVE: Antimicrobial resistance among the bacteria present in ready-to-eat foods like vegetable salads is an emerging concern today. The current study was undertaken to investigate the presence of multi-drug resistant extended-spectrum ß-lactamase (ESBL) producing E. coli and Salmonella spp. in raw vegetable salads served at hotels and restaurants in Bharatpur. A total of 216 salad samples were collected from three different grades of hotels and restaurants and examined for the presence of E. coli and Salmonella spp. in Microbiology laboratory of Birendra Multiple Campus by conventional microbiological techniques. RESULTS: Out of 216 samples, 66 samples (35.2%) showed the presence of Salmonella spp. whereas E. coli was recovered from 29 (13.4%) samples of which 3 samples harbored E. coli O157: H7. Antibiotic susceptibility testing revealed that 9 (13.6%) Salmonella and 4 (13.8%) E. coli isolates were detected as multi-drug resistant. Total ESBL producers reported were 5 (7.57%) Salmonella and 4 (13.8%) E. coli. The study also assessed a significant association between occurrence of E. coli and Salmonella with different grades of hotels and restaurants, personal hygiene and literacy rate of chefs and with the type of cleaning materials used to wash knives and chopping boards (p < 0.05). The findings suggest an immediate need of attention by the concerned authorities to prevent the emergence and transmission of food-borne pathogens and infections antimicrobial resistance among them.


Assuntos
Farmacorresistência Bacteriana Múltipla , Escherichia coli O157/isolamento & purificação , Salmonella/isolamento & purificação , Verduras/microbiologia , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/metabolismo , Contaminação de Alimentos/prevenção & controle , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Higiene das Mãos/normas , Habitação/normas , Habitação/estatística & dados numéricos , Humanos , Testes de Sensibilidade Microbiana , Nepal , Restaurantes/normas , Restaurantes/estatística & dados numéricos , Salmonella/efeitos dos fármacos , Salmonella/metabolismo
17.
Food Microbiol ; 84: 103276, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421762

RESUMO

The diarrheal type of food poisoning caused by enteropathogenic Bacillus cereus has been linked to various exotoxins. Best described are the non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and cytotoxin K (CytK). Due to the ubiquitous prevalence of B. cereus in soil and crops and its ability to form highly resistant endospores, contaminations during food production and processing cannot be completely avoided. Although phylogenetically closely related, enteropathogenic B. cereus strains show a high versatility of their toxic potential. Thus, functional tools for evaluating the pathogenic potential are urgently needed in order to predict hazardous food contaminations. As the diarrheal syndrome is the result of a toxico-infection with enterotoxin production in the intestine, the entire passage of the bacteria within the host, from spore survival in the stomach, spore germination, host cell adherence, and motility, to enterotoxin production under simulated intestinal conditions was compared in a panel of 20 strains, including high pathogenic as well as apathogenic ones. This approach resulted in an overarching virulence analysis scheme. In parallel, we searched for potential toxico-specific secreted markers to discriminate low and high pathogenic strains. To this end, we targeted known exotoxins using an easy to implement immunoblotting approach as well as a caseinolytic exoprotease activity assay. Overall, Nhe component B, sphingomyelinase, and exoproteases showed good correlation with the complex virulence analysis scheme and can serve as a template for future fast and easy risk assessment tools to be implemented in routine diagnostic procedures and HACCP studies.


Assuntos
Bacillus cereus/patogenicidade , Enterotoxinas/metabolismo , Contaminação de Alimentos/análise , Microbiologia de Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Proteínas de Bactérias/metabolismo , Doenças Transmitidas por Alimentos/microbiologia , Filogenia , Virulência , Fatores de Virulência/metabolismo
18.
Food Microbiol ; 84: 103270, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421783

RESUMO

Vibrio parahaemolyticus is the leading bacterial cause of seafood-associated gastroenteritis worldwide. Moreover, infections and outbreaks caused by V. parahaemolyticus has kept increasing over the last two decades. In this study, we investigated the genetic diversity, virulence factors and farm-to-table spread pattern of V. parahaemolyticus by analyzing 383 genomes of food-associated isolates. These strains were isolated from diverse sample types from six provinces of China in 2014, being classified into three tiers of the farm-to-table spread process: food production, circulation and consumption. The genetic diversity of V. parahaemolyticus in different classifications, including geographical location, sample type, source and spread tier, was similar, as the median number of pairwise SNPs within each classification was between 33,013 and 33,659. Specifically, there was no clear boundaries in genetic diversity of the isolates from inland vs. coastal provinces, as well as of those from freshwater vs. seawater products. Moreover, the virulence genes and genomic islands were only found in a small number of isolates, indicating a low disease risk of the food-associated isolates in this study. By further exploring 28 recently emerged clonal groups, we identified seven farm-to-table spread events, showing a common pattern of single-source radial spread accompanied with occasional gene gain/loss events. Generally speaking, our work highlighted the colonization of V. parahaemolyticus in inland provinces and freshwater environment, and provided a snapshot of the farm-to-table spread pattern of V. parahaemolyticus food-associated isolates. Our results showed the feasibility of tracking the farm-to-table spread of foodborne pathogen, which would help construct the whole genome sequencing-based molecular tracking network in the future.


Assuntos
Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Variação Genética , Vibrio parahaemolyticus/genética , Fatores de Virulência/genética , Animais , Técnicas de Tipagem Bacteriana , China , Surtos de Doenças , Ilhas Genômicas , Humanos , Tipagem de Sequências Multilocus , Filogenia , Frutos do Mar/microbiologia , Vibrioses/microbiologia , Vibrio parahaemolyticus/classificação , Vibrio parahaemolyticus/isolamento & purificação , Virulência/genética
19.
Food Microbiol ; 84: 103233, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421792

RESUMO

Globally, V. parahaemolyticus infection is a leading cause of bacterial diarrheal diseases. Pathogenic V. parahaemolyticus strains that produce hemolysins are responsible for these diseases. The composition of pathogenic and non-pathogenic V. parahaemolyticus and the change of the bacterial composition before and after traditional selective enrichment in a single sample associated with disease outbreak remain unclear. We investigated an outbreak by using next generation sequencing and digital PCR to address those questions. NGS showed that the V. parahaemolyticus caused the outbreak belonged to s single clone. In contrast, among the seven non-pathogenic V. parahaemolyticus isolated from the suspected food sample, 4 serotypes and 6 PFGE patterns were identified. And nearly 70,000 SNPs were identified among the non-pathogenic strains. This result confirmed that the outbreak was caused by V. parahaemolyticus. Furthermore, NGS results clearly showed the diversity of non-pathogenic V. parahaemolyticus in a single contaminated food sample. The ratios of non-pathogenic and pathogenic V. parahaemolyticus were 31.41 and 620.11 in the original and enriched food samples respectively showed by digital PCR. Meta-genomic data indicated the top 3 species were Weissella cibaria, Weissella confusa, and Enterobacter cloacae in the original food sample, and Vibrio sp Ex25, Vibrio sp 712i, and V. parahaemolyticus in the enriched sample. Therefore, the combing of NGS and digital PCR results showed that traditional Vibrio selective enrichment media could facilitate the growth of Vibrios, however, it provided no advantages to pathogenic V. parahaemolyticus. Hence, our results indicated that the traditional culture methods alone may lead to wrong conclusions and so improvements in culture methods are needed.


Assuntos
Diarreia/microbiologia , Surtos de Doenças , Doenças Transmitidas por Alimentos/etiologia , Doenças Transmitidas por Alimentos/microbiologia , Vibrioses/diagnóstico , Vibrio parahaemolyticus/genética , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Reação em Cadeia da Polimerase , Vibrioses/microbiologia , Vibrio parahaemolyticus/patogenicidade
20.
Future Microbiol ; 14: 885-898, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31368788

RESUMO

Aim: The aim of this study is to formulate a new single nonselective pre-enrichment medium (ELSS) that can support the concurrent growth of four major foodborne pathogens containing E. coli O157: H7, L. monocytogenes, S. aureus and S. enterica serovar Entertidis to develop a multiplex TaqMan Real-time PCR (mRT-PCR). Methods: The mRT-PCR with a new pre-enrichment was carried out for simultaneous detection and quantification of these foodborne bacteria. Results: By using mRT-PCR after 16 h pre-enrichment in ELSS, the detection limit of each pathogen was 1 CFU/25 ml contaminated milk, as well as inclusivity and exclusivity reached 100%. Conclusion: The mRT-PCR assay with pre-enrichment step is a fast and reliable technique for detecting single or multiple pathogens in food products.


Assuntos
Bactérias/genética , Técnicas Bacteriológicas/métodos , Microbiologia de Alimentos/métodos , Doenças Transmitidas por Alimentos/microbiologia , Leite/microbiologia , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Meios de Cultura , DNA Bacteriano/genética , Escherichia coli O157/genética , Escherichia coli O157/crescimento & desenvolvimento , Escherichia coli O157/isolamento & purificação , Listeria monocytogenes/genética , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/isolamento & purificação , Reação em Cadeia da Polimerase , Salmonella enteritidis/genética , Salmonella enteritidis/crescimento & desenvolvimento , Salmonella enteritidis/isolamento & purificação , Sensibilidade e Especificidade , Staphylococcus aureus/genética , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação
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