scholarly journals Characterization of a Campylobacter jejuni VirK Protein Homolog as a Novel Virulence Determinant

2009 ◽  
Vol 77 (12) ◽  
pp. 5428-5436 ◽  
Author(s):  
Veronica Novik ◽  
Dirk Hofreuter ◽  
Jorge E. Galán
Keyword(s):  
United States ◽  
Campylobacter Jejuni ◽  
Virulence Factors ◽  
Unique Feature ◽  
The United States ◽  
Genetic Screen ◽  
Food Borne ◽  
Food Borne Illness ◽  
Antimicrobial Peptide Resistance

ABSTRACT Campylobacter jejuni is a leading cause of food-borne illness in the United States. Despite significant recent advances, its mechanisms of pathogenesis are poorly understood. A unique feature of this pathogen is that, with some exceptions, it lacks homologs of known virulence factors from other pathogens. Through a genetic screen, we have identified a C. jejuni homolog of the VirK family of virulence factors, which is essential for antimicrobial peptide resistance and mouse virulence.

scholarly journals Clostridium perfringens: Sporulation, Spore Resistance and Germination

1970 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I-Hsiu Huang ◽  
Deepa Raju ◽  
Daniel Paredes-Sabja ◽  
Mahfuzur R Sarker
Keyword(s):  
United States ◽  
Clostridium Perfringens ◽  
Anaerobic Bacteria ◽  
The United States ◽  
Genome Sequences ◽  
Enteric Diseases ◽  
Spore Resistance ◽  
Food Borne ◽  
Food Borne Illness ◽  
Spore Proteins

Clostridium perfringens are Gram-positive, endospore-forming, anaerobic bacteria with the ability to cause enteric diseases both in human and domesticated animals. As one of the leading cause of food-borne illness in the United States, certain C. perfringens type A isolates exert their action through the production of C. perfringens enterotoxin (CPE), which is expressed only during spore formation. In addition, C. perfringens spores are highly resistant to heat and other environmental factors. Since genome sequences of three C. perfringens strains have been annotated and made public, efforts have been made towards understanding the initiation of sporulation and identifying the key differences between Clostridium and Bacillus sporulation phosphorelay. Small, acid soluble spore proteins (SASPs) have been shown to be required for resistance of C. perfringens spores to heat. Work is also underway to identify nutrient signals required for C. perfringens spore germination. Keywords: Clostridium perfringens, Endospore, Small, acid soluble spore protein (SASP), Heat resistance, GerminationDOI: http://dx.doi.org/10.3329/bjm.v24i1.1229 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 1-8

scholarly journals Enterotoxigenicity and Genetic Relatedness of Clostridium perfringens Isolates from Retail Foods in the United States

2003 ◽  
Vol 69 (3) ◽  
pp. 1642-1646 ◽  
Author(s):  
Yuan-Tong Lin ◽  
Ronald Labbe
Keyword(s):  
United States ◽  
Clostridium Perfringens ◽  
Genetic Relatedness ◽  
The United States ◽  
Food Samples ◽  
Gene Probe ◽  
Cell Extracts ◽  
Food Borne ◽  
Food Borne Illness ◽  
The 1960S

ABSTRACT Clostridium perfringens is a leading cause of bacterial food-borne illness in countries where consumption of meat and poultry is high. For example, each year in the United States, this organism is the second or third most common cause of confirmed cases of food-borne illness. Surveys of the incidence of this organism in retail foods were done in the 1960s without regard to whether isolates were enterotoxigenic. It is now known that not all strains of this organism possess the enterotoxin gene responsible for illness. We examined the incidence of this organism in 131 food samples from retail food stores in an area of the northeastern United States. Forty isolates were obtained by using the iron milk method at 45°C, with confirmation by use of motility nitrate and lactose gelatin media. The presence of the C. perfringens enterotoxin (cpe) and alpha toxin (cpa) genes was determined by PCR using previously published primer sequences. All isolates possessed cpa. None of the isolates were identified as carrying the cpe gene by this method or by another method using a digoxigenin-labeled gene probe. Consistent with these results, none of the sporulating-cell extracts contained enterotoxin as determined by reverse passive latex hemagglutination. Pulsed-field gel electrophoresis was used to determine the genetic relatedness of the isolates. About 5% of the isolates were considered to be closely related (2- to 3-band difference). The others were considered to be unrelated to one another. The results demonstrate the rarity of cpe+ strains in retail foods and the genetic diversity among nonoutbreak strains.

Can genetic engineering prevent food-poisoning?

1969 ◽  
Vol 15 (3) ◽  
Author(s):  
Henry Miller
Keyword(s):  
United States ◽  
Recombinant Dna ◽  
Organic Food ◽  
Food Poisoning ◽  
The United States ◽  
Food Irradiation ◽  
Recombinant Dna Technology ◽  
Ample Evidence ◽  
Food Borne ◽  
Food Borne Illness

The largest outbreak of food-borne illness in a decade sickened over 1400 people in various parts of the United States in 2008. Originally thought to be caused by tomatoes contaminated with Salmonella saintpaul, an investigation by federal agencies found that Mexican jalapeno peppers and possibly serrano peppers were the culprits.These sorts of outbreaks are not at all rare: A search for ‘food poisoning’ on the website of the US Centers for Disease Control and Prevention (CDC) (on 10 November 2008) yielded more than 5300 hits, and the CDC estimates that each year 76 million cases of food-borne illness occur and more than 300 000 persons are hospitalised and 5000 die. This raises various questions of importance to consumers. Who or what is responsible for the problem? How does such contamination occur, and what can be done to prevent recurrences?Unfortunately, growers of fresh produce cannot protect us 100 per cent of the time. Modern farming operations – especially the larger ones – already employ strict standards and safeguards designed to keep food free of pathogens. And most often they’re highly effective: Americans’ food is not only the least expensive but also the safest, in the history of humankind.The vast majority of food poisoning results from consumers’ improper handling of food – in particular, from inadequately cooking chicken or permitting the juices from raw poultry to contaminate other foods.Because agriculture is an outdoor activity and subject to myriad unpredictable challenges, there are limits to how safe we can make it. If the goal is to make a cultivated field completely safe from microbial contamination, the only definitive solution is to pave it over and build a parking lot on it. But we’d only be trading very rare agricultural mishaps for fender-benders.Nor can we rely on processors to remove the pathogens from food in every case. The 2006 spinach-based outbreak of illness served as a reminder that our faith in processor labels such as ‘triple washed’ and ‘ready to eat’ must be tempered with at least a little scepticism. Processors were quick to proclaim the cleanliness of their own operations and deflect blame toward growers. But all of those in the food chain share responsibility for food safety and quality.In fairness to processors, there is ample evidence to suggest that no amount of washing will rid produce entirely of all pathogens. The reason is that the contamination may occur not on the plant, but in it. Exposure to Salmonella, E. coli or other microorganisms at key stages of the growing process may allow them to be introduced into the plant's vascular system.In the longer term, technology has an important role – or more accurately, it would have if only the organic food advocates and other activists would permit it. The Food and Drug Administration recently added fresh spinach and iceberg lettuce to the short list of foods that companies can irradiate to kill off many dangerous pathogens. (Regulators had already approved irradiation of meat, poultry, spices, oysters, clams and mussels.) Food irradiation is an important, safe and effective tool that has been vastly under-used, largely due to opposition from the organic food lobby. Their resistance is scandalous – and murderous: ‘If even 50% of meat and poultry consumed in the United States were irradiated, the potential impact of food borne disease would be a reduction [of] 900,000 cases and 300 deaths’, according to Michael Osterholm, Director of the Center for Infectious Disease Research at the University of Minnesota.But irradiation is not a panacea. Although it quite effectively kills the bacteria, it does not inactivate the potent toxins secreted by certain bacteria such as Staphylococcus aureus and Clostridium botulinum, and the approved doses are too low to kill most viruses. The toxins can cause serious illness or death even in the absence of live bacteria themselves.There is technology available today that can both inhibit microorganisms’ ability to grow within plant cells and block the effects of the biochemical and structural features that enable bacteria to cause disease. This same technology can be employed to produce antibodies that can be administered to infected patients to neutralise toxins and other harmful molecules and can even be used to produce therapeutic proteins (such as lactoferrin and lysozyme) that are safe and effective treatments for diarrhoea, the primary symptom of food poisoning.But organic producers won’t embrace this triple-threat technology, even if it would keep their customers from food-borne illness. The technology in question is recombinant DNA technology, or gene-splicing (also known as ‘genetic modification’, or GM) – an advance the organic lobby has repeatedly vilified and rejected.For organic marketers and food activists, the irony is more bitter than fresh-picked radicchio. The technology that offers a potent new weapon to assure the safety of foods is the one they’ve fought hardest to forestall and confound.In view of the huge burden of illnesses and deaths caused by bacteria and viruses in food, will the organic lobby rethink their opposition to biotechnology? Will they begin to appreciate the ways in which this technology can save lives and advance their industry? Will they permit science, common sense and decency to trump ideology? When figs can fly.

scholarly journals Prevalence and Characterization of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolates from Commercial Ground Beef in the United States

2011 ◽  
Vol 77 (6) ◽  
pp. 2103-2112 ◽  
Author(s):  
Joseph M. Bosilevac ◽  
Mohammad Koohmaraie
Keyword(s):  
United States ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Iron Acquisition ◽  
Ground Beef ◽  
Dna Amplification ◽  
The United States ◽  
Virulence Plasmid ◽  
Beef Industry

ABSTRACTEscherichia coliO157:H7 is a Shiga toxin (stx)-producingE. coli(STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n= 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that containedstx1and/orstx2was attempted. Of the 1,006 positive ground beef samples screened forstx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa,iha,lifA), toxicity (cnf,subA,astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP,etpD,toxB,katP,toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-islandnlegenes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence ofeae,subA, andnlegenes.

scholarly journals Isolation and characterization of novel reassortant mammalian orthoreovirus from pigs in the United States

2021 ◽  
pp. 1-43
Author(s):  
Liping Wang ◽  
Yan Li ◽  
Timothy Walsh ◽  
Zhenyu Shen ◽  
Yonghai Li ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Isolation And Characterization ◽  
Mammalian Orthoreovirus

Food-Borne Disease Outbreaks in the United States, 1973

1975 ◽  
Vol 132 (2) ◽  
pp. 224-228 ◽  
Author(s):  
J. M. Hughes ◽  
M. H. Merson ◽  
R. A. Pollard
Keyword(s):  
United States ◽  
Disease Outbreaks ◽  
The United States ◽  
Food Borne

Phylogenetic and phenotypic characterization of Fomes fasciatus and Fomes fomentarius in the United States

Mycologia ◽  
2013 ◽  
Vol 105 (6) ◽  
pp. 1524-1534 ◽  
Author(s):  
Meghan A. McCormick ◽  
Larry F. Grand ◽  
Justin B. Post ◽  
Marc A. Cubeta
Keyword(s):  
United States ◽  
The United States ◽  
Phenotypic Characterization ◽  
Fomes Fomentarius

scholarly journals Phenotypic Characterization of Recent Clonal Lineages of Phytophthora infestans in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 873-881 ◽  
Author(s):  
G. Danies ◽  
I. M. Small ◽  
K. Myers ◽  
R. Childers ◽  
W. E. Fry
Keyword(s):  
United States ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
The United States ◽  
Phenotypic Characterization ◽  
Phenotypic Traits ◽  
Mating Types ◽  
Late Blight Disease ◽  
Blight Disease

Phytophthora infestans, the causal agent of late blight disease, has been reported in the United States and Canada since the mid-nineteenth century. Due to the lack of or very limited sexual reproduction, the populations of P. infestans in the United States are primarily reproducing asexually and, thus, show a simple genetic structure. The emergence of new clonal lineages of P. infestans (US-22, US-23, and US-24) responsible for the late blight epidemics in the northeastern region of the United States in the summers of 2009 and 2010 stimulated an investigation into phenotypic traits associated with these genotypes. Mating type, differences in sensitivity to mefenoxam, differences in pathogenicity on potato and tomato, and differences in rate of germination were studied for clonal lineages US-8, US-22, US-23, and US-24. Both A1 and A2 mating types were detected. Lineages US-22, US-23, and US-24 were generally sensitive to mefenoxam while US-8 was resistant. US-8 and US-24 were primarily pathogenic on potato while US-22 and US-23 were pathogenic on both potato and tomato. Indirect germination was favored at lower temperatures (5 and 10°C) whereas direct germination, though uncommon, was favored at higher temperatures (20 and 25°C). Sporangia of US-24 released zoospores more rapidly than did sporangia of US-22 and US-23. The association of characteristic phenotypic traits with genotype enables the prediction of phenotypic traits from rapid genotypic analyses for improved disease management.

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