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

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.

1970 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I-Hsiu Huang ◽  
Deepa Raju ◽  
Daniel Paredes-Sabja ◽  
Mahfuzur R Sarker

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


2009 ◽  
Vol 77 (12) ◽  
pp. 5428-5436 ◽  
Author(s):  
Veronica Novik ◽  
Dirk Hofreuter ◽  
Jorge E. Galán

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.


1969 ◽  
Vol 15 (3) ◽  
Author(s):  
Henry Miller

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.


2020 ◽  
Vol 1 (1) ◽  
pp. 141-153
Author(s):  
Adolphus G. Belk ◽  
Robert C. Smith ◽  
Sherri L. Wallace

In general, the founders of the National Conference of Black Political Scientists were “movement people.” Powerful agents of socialization such as the uprisings of the 1960s molded them into scholars with tremendous resolve to tackle systemic inequalities in the political science discipline. In forming NCOBPS as an independent organization, many sought to develop a Black perspective in political science to push the boundaries of knowledge and to use that scholarship to ameliorate the adverse conditions confronting Black people in the United States and around the globe. This paper utilizes historical documents, speeches, interviews, and other scholarly works to detail the lasting contributions of the founders and Black political scientists to the discipline, paying particular attention to their scholarship, teaching, mentoring, and civic engagement. It finds that while political science is much improved as a result of their efforts, there is still work to do if their goals are to be achieved.


1975 ◽  
Vol 132 (2) ◽  
pp. 224-228 ◽  
Author(s):  
J. M. Hughes ◽  
M. H. Merson ◽  
R. A. Pollard

2018 ◽  
Vol 48 (4) ◽  
pp. 403-440 ◽  
Author(s):  
Jérôme Lamy

The TOPEX/POSEIDON satellite mission to observe the oceans triggered the formation of the new specialty of space oceanography from the 1970s to 1990s. Previously, in the 1960s in the United States, traditional oceanographers had shown little interest in the possibilities of space and thus space engineers and physicists worked on the first missions (Seasat in particular). TOPEX/POSEIDON brought together two projects, one American (TOPEX) and the other French (POSEIDON). The gradual crystallization of the disciplinary specialty of space oceanography occurred by making available a platform of instruments able to meet an ensemble of varied needs. Battery failures just before the launch of the joint mission meant that the mission had to focus on the essentials (notably El Niño effects). Subsequently, the discovery of a significant rise in sea levels due to global warming resulted in space oceanography becoming a recognized specialty. The case of TOPEX/POSEIDON shows the original ways in which instruments gained a place in the very large range of oceanographic techniques.


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