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Abstract Escherichia coli O157:H7 is a foodborne pathogen implicated in numerous outbreaks worldwide that has the ability to cause extra-intestinal complications in humans. The Enteropathogens Division of the Central Public Health Laboratory (CPHL) in Paraguay is working to improve the genomic characterization of Shiga toxin-producing E. coli (STEC) to enhance laboratory-based surveillance and investigation of foodborne disease outbreaks. Whole genome sequencing (WGS) is proposed worldwide to be used in the routine laboratory as a high-resolution tool that allows to have all the results in a single workflow. This study aimed to carry out for the first time, the genomic characterization by WGS of nine STEC O157:H7 strains isolated from human samples in Paraguay. We were able to identify virulence and resistance mechanisms, MLST subtype, and even establish the phylogenetic relationships between isolates. Furthermore, we detected the presence of strains belonging to hypervirulent clade 8 in most of the isolates studied.
Resumen Escherichia coli O157:H7 es un patógeno transmitido por alimentos implicado en numerosos brotes en todo el mundo y es capaz de causar complicaciones extraintestinales en humanos. La sección de «Enteropatógenos¼ del Laboratorio Central de Salud Pública trabaja en mejorar la caracterización genómica de STEC, de modo de potenciar la vigilancia laboratorial y la investigación de brotes de enfermedades transmitidas por alimentos. La secuenciación de genoma completo (WGS, por sus siglas en inglés) se propone a nivel mundial como una herramienta de alta resolución para ser utilizada en el laboratorio de rutina, ya que permite obtener todos los resultados en un único proceso. El objetivo de este trabajo fue llevar a cabo, por primera vez, la caracterización genómica por WGS de nueve cepas STEC O157:H7 aisladas en Paraguay a partir de muestras de origen humano. Pudimos identificar los factores de virulencia, los mecanismos de resistencia, el subtipo MLST, e incluso pudimos establecer la relación filogenética entre los aislamientos. Además, detectamos que la mayoría de las cepas pertenecían al clado hipervirulento 8.
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Objective@# To investigate the contamination of foodborne pathogens in market-sold food in Fuyang District, Hangzhou City, so as to provide insights into intensified supervision of food safety and management of foodborne diseases.@*Methods@# A total of 1 176 market-sold food samples belonging to 11 categories were collected from Fuyang District from 2019 to 2022, and nine foodborne pathogens, including Salmonella, Vibrio parahaemolyticus and Yersinia enterocolitica, were detected according to the National Handbook for Surveillance of Risk of Food Contamination and Hazardous Factors in 2019 and national criteria for food microbiological testing. The detection of foodborne pathogens was analyzed in food samples with different categories and sources. @*Results@#Foodborne pathogens were detected in 332 out of 1 176 market-sold food samples, with a detection rate of 28.23%, and the detection rates of V. parahaemolyticus, Enterobacter sakazakii, non-O1/non-O139 V. cholerae, Y. enterocolitica, Vibrio vulnificus, Bacillus cereus, Staphylococcus aureus, Salmonella and Listeria monocytogenes were 39.47%, 36.92%, 35.48%, 34.09%, 13.85%, 12.26%, 8.58%, 6.65% and 2.53%. The detection rates of foodborne pathogens were 38.36%, 24.90%, 15.48%, 11.90%, 5.68%, 5.56%, 4.48%, 1.67%, 1.25% and 0.81% in aquatic food and its products, meat and meat products, local specialty food, catering food, flavoring, foods for special dietary uses, milk and milk products, egg and egg products, cooked food and other food, respectively, while foodborne pathogens were not detected in frozen drinks. In addition, the detection rates of foodborne pathogens were 24.97%, 15.19%, 9.88%, 7.89% and 7.23% in farmers' markets, supermarkets, online stores, vendors and restaurants, respectively. @*Conclusions@#A high detection rate of V. parahaemolyticus, E. sakazakii and non-O1/non-O139 V. cholerae was found in market-sold food in Fuyang District from 2019 to 2022, and the contamination of foodborne pathogens was serious in aquatic food and its products, meat and meat products and local specialty food.
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ObjectiveThe contamination of foodborne pathogens in ready-to-eat fruits and vegetables in Shanghai was analyzed to provide a scientific basis for food safety， risk assessment and related supervision. MethodsFrom June to September 2021， a total of 143 batches of12 kinds of ready-to-eat fruits and vegetables such as lettuce， chicory， and cherry tomatoes were collected from farmers’ markets， supermarkets， and e-commerce platforms. The total number of bacterial colonies， Salmonella， Listeria monocytogenes， Staphylococcus aureus， Cronobacter spp. and Shiga toxin-producing Escherichia coli in the samples were tested according to National Food Contamination and Harmfulness Risk Monitoring Manual. ResultsAmong the 143 batches， foodborne pathogens were detected in 68 batches， with a total detection rate of 47.55% （68/143）. A total of 79 strains of foodborne pathogens were detected. The detection rate of Staphylococcus aureus was the highest （32.87%， 47/143）， followed by Cronobacter spp. （20.98%， 30/143）， Salmonella （0.70%， 1/143）， Listeria monocytogenes （0.70%， 1/143）， Shiga toxin-producing Escherichia coli （0.00%）. Furthermore， the detection rate was higher in different ready-to-eat fruits and vegetables： chicory （17.33%）， cucumber （17.14%）， cherry tomatoes （16.00%）， and honeydew melon （15.38%）， respectively. Meanwhile， the contamination rate of pathogens in ready-to-eat fruits and vegetables from farmers’ markets， supermarkets， and e-commerce platforms was relatively high. ConclusionReady-to-eat fruits and vegetables in Shanghai are contaminated by foodborne pathogens. The prevention and control of the contamination of post-harvest fruits and vegetables should be strengthened to reduce the risk of foodborne disease outbreaks.
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Escherichia albertii is an emerging zoonotic enteropathogen which mainly causes infectious diarrhea. Since the discovery and naming of Escherichia albertii, it was found to be responsible for several outbreaks of foodborne gastroenteritis and widely distributed in avian and wild animals. Due to the lack of specific identification system, the global Escherichia albertii infections might be underestimated. Though avian has been considered as the important reservoir of Escherichia albertii, its role in disease transmission remains unclear. This study reviewed the biochemical properties, genomic characteristics, isolation and identification methods of Escherichia albertii, and its prevalence in human, host animals and food. The risk of Escherichia albertii infection and future perspectives in this field were also discussed.
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Aims@#This study aims to isolate lactic acid bacteria (LAB) from various food sources to obtain a potent strain against Listeria monocytogenes. @*Methodology and results@#A total of 68 LAB isolates were selected to evaluate their antimicrobial activity against L. monocytogenes, a foodborne pathogen and a causative agent of listeriosis. The selected isolate was identified and characterized. The isolate C23 from cabbage showed the highest antimicrobial activity against L. monocytogenes ATCC 7644 with inhibition ability of 73.94%. The isolate was closely related to Lactobacillus brevis by 16S rRNA sequencing and subsequently deposited in GenBank with an accession number of MN880215, named as L. brevis C23. The cell free supernatant (CFS) of L. brevis C23 had high tolerance in low pH and was able to withstand up to 60 °C. The proteinaceous nature of the antimicrobial agent was also confirmed through the enzymatic test. The CFS was stable on different detergents as well as bile salts. Under transmission electron microscopy (TEM), the inhibitory effect of CFS against L. monocytogenes was proven by causing cell lysis.@*Conclusion, significance and impact of study@#Bacteriocin-like inhibitory substances (BLIS) of L. brevis C23 showed very promising potential in food industrial application.
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Lactobacillales , Listeria monocytogenes , Foodborne Diseases , Sprains and StrainsABSTRACT
As the main factor leading to foodborne illnesses, foodborne pathogens have been attached great importance by people. The development of simple, rapid, high-sensitivity and low-cost food-borne pathogen detection methods is of great significance in reducing the incidence of foodborne diseases. Biosensor technology is a new micro-analysis technology developed by multi-disciplinary cross-infiltration. It has the characteristics of high sensitivity and fast analysis speed, and is widely used in the detection of food-borne pathogens. This paper introduces the basic principles of biosensors, summarizes the application of common biosensors in the detection of foodborne pathogens, and prospects for future development.
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Humans , Biosensing Techniques , Food Microbiology , Foodborne DiseasesABSTRACT
Quorum sensing (QS) plays a major role in the outbreak mechanism of foodborne diseases caused by food poisoning and food spoilage. QS affects the formation of cell membrane and pathogenicity ofpathogenic bacteria. Through the in-depth understanding of QS molecules of food-borne pathogens, we describe here the types of signal molecules produced by Gram-negative and Gram-positive bacteria, and the differences in QS molecules. Meanwhile, we introduce the detection of QS molecules by different technologies. According to the influence of QS on food, we propose also future research needs for the control of foodborne pathogenic bacteria.
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Gram-Negative Bacteria , Gram-Positive Bacteria , Quorum SensingABSTRACT
We evaluated the tolerance and pathogenesis of foodborne pathogens with a simulated gastro-intestinal tract model that simulates the chemical, physical and biological effects of human digestion process under laboratory conditions. This could be used to study the tolerance, pathogenesis, gut microbiota interaction and vaccine development of foodborne pathogens, so as to contribute to control and treatment of foodborne pathogens. This review introduces the applications of simulated gastro-intestinal tract model tp evaluate foodborne pathogens, which includes in-vitro static gastro-intestinal model, in-vitro dynamic gastro-intestinal model, conventional animal model and humanized animal model. And the concepts and characteristics of all models are described in detail. Also, the shortcomings of existing models are analyzed, and improvements of artificial gastro-intestinal tract model are prospected. In conclusion, this review could provide comprehensive data for promoting the progress of studying tolerance and pathogenesis of foodborne pathogens.
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Objective To study the serotypes and molecular characteristics of foodborne Salmonella in Yunnan Province using pulsed field gel electrophoresis (PFGE) and to establish PFGE fingerprint database. Methods This study was carried out on the basis of the Serological typing of 322 strains of foodborne Salmonella which was isolated from Yunnan national foodborne disease surveillance from 2013 to 2016. The clustering analysis was conducted on 148 strains of Salmonella DNA restriction enzyme map by using the software of BioNumerics. Fingerprint database was established through the comparison of clustering analysis correlation on bacterial strain. Results The serotype of 322 strains of Salmonella mainly included A, B, C, D, E, F, G and other 7 groups,among which Salmonella typhimurium was the major type, accounting for 11.4% (37/322) . Cluster analysis was applied using BioNumerics software in 148 strains of Salmonella DNA restriction enzyme map. According to the different number and the different positions, electrophoresis strips were divided into 102 different PFGE patterns (Figure 1) , which was categorized into 39 clusters if 90% of the strips was similar. Conclusion Foodborne salmonella molecular classification is complex. Salmonella typhimurium is the major type. PFGE belt type presents diversity.
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Bacillus cereus es una bacteria genéticamente diversa que se encuentra comúnmente en el ambiente. Contamina los alimentos afectando la salud humana, al ingerir el microorganismo y/o sus toxinas, la emética o las enterotoxinas. En Colombia son escasos los reportes de intoxicación por B. cereus y se estima que hay un gran subregistro. Por lo anterior, se recomienda aumentar la vigilancia de este patógeno y realizar estudios sobre aspectos relevantes que permitan aplicar medidas de control para disminuir las intoxicaciones por B. cereus. El objetivo de esta revisión bibliográfica es presentar información actualizada sobre B. cereus, que incluye aspectos de su biología, taxonomía, toxinas, alimentos que contamina y metodologías para detectar, prevenir y controlar este microorganismo. La información presentada es de utilidad para el público en general, especialmente personas vinculadas al sector de alimentos, inocuidad alimentaria y control de procesos.
Bacillus cereus is a genetically diverse bacterium commonly found in the environment. It contaminates food, thus affecting human health upon ingestion of the microorganism and/or its toxins, the emetic or enterotoxins. In Colombia, reports of intoxication by B. cereus are scarce and under-registration is presumed. Because of this, it is recommended to increase surveillance of this pathogen and to develop studies on relevant aspects that allow the application of control measures to reduce intoxications by B. cereus. The aim of this review is to present current information on B. cereus, including aspects of its biology, taxonomy, toxins, food that it contaminates and methodologies for the detection, prevention and control of this microorganism. This information is useful for the general public, especially people involved with the food sector, food safety and process control.
Bacillus cereus é uma bactéria geneticamente diversa normalmente encontrada no ambiente. Contamina os alimentos dos humanos e estes acabam prejudicados quando ingerem o microorganismo e/ou suas toxinas, a emética ou as enterotoxinas. Na Colômbia existem poucos relatórios de intoxicação por B. cereus, mas se estima um grande sub-registro. Essa estimação faz com que seja recomendável aumentar a vigilância deste patógeno e estudar aspetos relevantes que permitam aplicar medidas de controle, para diminuir as intoxicações por B. cereus. O objetivo desta revisão bibliográfica é apresentar informação atualizada sobre a B. cereus, incluindo aspectos da sua biologia, taxonomia, toxinas, alimentos que pode contaminar e metodologias para detectar, prevenir e controlar este microorganismo. Esta informação é útil para o público geral, especialmente para pessoas ligadas ao setor dos alimentos, à segurança alimentar e ao controle de processos
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The aim of this study was to evaluate the bacterial and fungal quality of minimally-processed vegetables (MPV) and sprouts. A total of 116 samples of fresh-cut vegetables, ready-to-eat salads, and mung bean and wheat sprouts were randomly collected and analyzed. The load of aerobic mesophilic bacteria was minimum and maximum in the fresh-cut vegetables and fresh mung bean sprouts respectively, corresponding to populations of 5.3 and 8.5 log CFU/g. E. coli O157:H7 was found to be absent in all samples; however, other E. coli strains were detected in 21 samples (18.1%), and Salmonella spp. were found in one mung bean (3.1%) and one ready-to-eat salad sample (5%). Yeasts were the predominant organisms and were found in 100% of the samples. Geotrichum, Fusarium, and Penicillium spp. were the most prevalent molds in mung sprouts while Cladosporium and Penicillium spp. were most frequently found in ready-to-eat salad samples. According to results from the present study, effective control measures should be implemented to minimize the microbiological contamination of fresh produce sold in Tehran, Iran.
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This is the first study conducted in Grenada, with a population of approximately 108,000, to quantify the magnitude, distribution, and burden of self-reported acute gastroenteritis (AGE). A retrospective population survey was conducted in October 2008 and April 2009 and a laboratory survey from October 2008 to September 2009. The estimated monthly prevalence of AGE was 10.7% (95% CI 9.0-12.6; 1.4 episodes/ person-year), with a median of 3 days of illness. Of those who reported AGE, 31% sought medical care (stool samples were requested from 12.5%); 10% took antibiotics; 45% took non-prescribed medication; and 81% reported restricted activity. Prevalence of AGE was significantly higher among children aged <5 years (23.5%, p<0.001). Of the AGE stool samples submitted to the laboratory for analysis, 12.1% were positive for a foodborne pathogen. Salmonella enteritidis was the most common foodborne pathogen associated with AGE-related illness. The estimated percentage of underreporting of syndromic AGE to the Ministry of Health was 69%. In addition, for every laboratory-confirmed foodborne/AGE pathogen, it was estimated that there were 316 additional cases occurring in the population. The minimum estimated cost associated with treatment for AGE was US$ 703,950 each year, showing that AGE has a potentially significant economic impact in Grenada.
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Although many rapid and high throughput molecular methods have been developed in the recent years for the multiplex detection of foodborne pathogens, the simultaneous recovery and enrichment of sublethally injured cells is still a problem that needs to be considered. Combined with previous established multiplex real-time PCR assay, the capability of simultaneous recovery and enrichment of sublethally injured Salmonella, E. coli O157:H7 and L. monocytogenes cells was evaluated in a multiplex selective enrichment broth SEL. The injured cells were obtained by heat shock. After evaluation of different procedures, 1 h of recovery period prior to 20 h of enrichment was proved to be necessary for the detection of less than 10 CFU/5 mL broth of injured L. monocytogenes. When the detection method was applied to artificially contaminated ground beef, all the three injured pathogens could be simultaneously detected without discrimination by real-time PCR combined with SEL broth, the detection limit was < 5 CFU/10 g ground beef. Comparatively, when BPW was employed as the enrichment broth in the same detection procedure, injured L. monocytogenes could not be detected if the initially spiked level was below 10² CFU/10 g ground beef. Considering the capability of co-enrichment and high detection effectiveness, the real-time PCR assay combined with SEL broth herein appears to be a promising tool for high-throughput screening of a large number of processed food samples, which require either single or multiple pathogen detection. More important, the sublethally injured foodborne pathogen cells were also detectable.
Subject(s)
Humans , Bacteriological Techniques/methods , Culture Media/chemistry , /isolation & purification , Food Microbiology/methods , Listeria monocytogenes/isolation & purification , Salmonella/isolation & purification , /growth & development , High-Throughput Screening Assays/methods , Listeria monocytogenes/growth & development , Molecular Diagnostic Techniques/methods , Multiplex Polymerase Chain Reaction/methods , Salmonella/growth & developmentABSTRACT
Listeria monocytogenes(L.monocytogenes)is an important human foodborne pathogen responsible for listeriosis.It is one of the hot topics in food safety area on how to detect L.monocytogenes rapidly and effectively.In recent years,its detection assays have a rapid development.The purpose is to summarize the culture-dependent enrichment,immunoassay-based and nucleic acid-based methods for detection of L.monocytogenes at present.Lastly,the review introduced the new strategy of detection assays.