Health and Medical News and Resources

General interest items edited by Janice Flahiff

Targeted antibacterial proteins may offer antibiotic alternative

Targeted antibacterial proteins may offer antibiotic alternative.(Company press release )

New publication demonstrates ability of Avidocin™ proteins to prevent and treat E. coli O157 diarrhea in animal study

SOUTH SAN FRANCISCO, CA — A novel antibacterial protein targeted against E. coli O157:H7 may offer a way to prevent or treat serious food-borne bacterial infections, as demonstrated in a study published in the December issue of Antimicrobial Agents and Chemotherapy. Results in an animal model of E. coli infection showed that the orally administered protein, developed by AvidBiotics, Inc., could prevent or treat E. coli O157:H7-induced diarrhea and intestinal inflammation when administered either on a preventative basis or after the onset of diarrhea. Moreover, animals treated with the protein also carried and shed fewer of the E. coli O157:H7 bacteria in their feces.

E. coli O157:H7 contamination of foods like ground meats or produce is a well-publicized public health problem, with life-threatening infection outbreaks reported around the world in recent years,” said Dean Scholl, Ph.D., lead author of the publication. “Antibiotics are contraindicated for patients infected with enterohemorrhagic E. coli (EHEC) strains like O157:H7, because many of those drugs induce the bacteria to produce and release harmful toxins. Anti-diarrheal medications also do not benefit infected patients, as they cause the bacteria to be retained in the intestines, leading to greater toxin exposure. Thus the successful development of treatments that can prevent infection or limit symptoms and disease duration and the possible further spread of harmful bacteria without increasing toxin release could benefit both individual patients and affected communities.”

The study published by Dr. Scholl and his collaborators at AvidBiotics and Brigham and Women’s Hospital/Harvard Medical School assessed AvidBiotics’ anti-E. coli O157 protein, termed an Avidocin™ protein, in a rabbit model of infection and reported that:

  • The Avidocin protein remained active within the treated animals’ intestinal tract for at least 24 hours post administration.
  • When given shortly after the animals were infected with E. coli O157:H7 but before they developed active disease, the Avidocin protein inhibited bacterial colonization and/or the symptoms of infection. Animals that received the highest dose of protein studied did not develop diarrhea at any time during the experiment. In contrast, animals given buffer alone developed typical diarrhea within 1-2 days after infection, which worsened by the 3rd day of the study.
  • Analyses of colon tissue showed less severe intestinal inflammation in Avidocin protein-treated animals compared to controls. Avidocin protein administration also greatly reduced the number of E. coli O157:H7 recovered from the intestine and the stool of treated animals.
  • When the anti-E. coli O157:H7 Avidocin protein was administered to infected animals already exhibiting disease symptoms, the existing diarrhea began to resolve in treated animals compared to animals treated with placebo. This reduction in diarrhea persisted until the experiment was terminated, 9 days post infection, at which time the feces of the treated animals appeared closer to feces from uninfected animals than the still largely liquid stool of the control animals. Thus, even after the onset of diarrhea in E. coliO157:H7-infected animals, administration of the anti-E. coli O157:H7 Avidocin protein could still mitigate the effects of infection.

“These findings suggest that an Avidocin protein targeted against E. coli O157:H7 offers promise for both the prevention and treatment of infection by this important enteric pathogen,” concluded Dr. Scholl. “Moreover, this agent provides several significant advantages over conventional antibiotics, including a lack of drug-induced shiga toxin production and unintended collateral damage to normal intestinal bacterial populations. Additionally those rare variants of E. coli O157:H7 that emerge resistant to the anti-E. coli O157:H7 Avidocin protein are likely to have compromised virulence, or disease-causing properties.”

About the Avidocin™ Protein Platform

AvidBiotics genetically engineers Avidocin proteins from R-type pyocins, antibacterial proteins produced by some Pseudomonas aeruginosa strains. These proteins specifically kill bacteria by binding to the bacterial cell and punching a hole in the cell envelope, causing membrane depolarization and ultimately cell death. AvidBiotics has previously demonstrated that Avidocin proteins can be engineered to recognize and kill in a highly targeted and specific manner a variety of bacteria, including E. coli, Salmonella, Shigella, Clostridium difficile, andYersinia pestis (the bacterium that causes plague), thus serving as a platform for the production of numerous highly specific antibacterial agents.

AvidBiotics is also currently developing Avidocin proteins against Acinetobacter, a bacterium associated with serious, often broadly antibiotic-resistant infections in Intensive Care Units and those incurred by U.S. military deployed in Iraq and Afghanistan. In addition to the human health care uses of the Avidocin™ technology, AvidBiotics is collaborating with food safety and hygiene company EcoLab to develop antibacterial proteins for use against E. coli O157:H7 in meat processing.

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About AvidBiotics

AvidBiotics is a developer of novel, non-antibody proteins as targeted therapeutics against bacteria, viral infections and cancers. The scaffolds of AvidBiotics’ proteins exhibit functional potency, e.g. killing, exceeding that of antibodies. AvidBiotics has two proprietary product platforms. The first is this new class of tailorable, targeted bactericidal agents for use in the treatment or prevention of specific bacterial infections. The second specifically flags virus-infected or cancerous cells for enhanced destruction by the Natural Killer and T cells of the potent innate immunity system. AvidBiotics focuses on human therapeutic applications of its technologies, both on its own and in partnership with governmental agencies and research institutions, while taking advantage of further near-term collaborative opportunities offered by specific applications of its products and technology platforms in areas such as food safety, biodefense and animal husbandry. For more information on AvidBiotics, please visit the company’s web site at http://www.avidbiotics.com.

November 21, 2011 Posted by | Consumer Health, Medical and Health Research News | , , , , | Leave a comment

E. coli in the countryside: whose problem is it anyway?

From the 25 August 2011 Science Daily article

Reducing the risks of catching E. coli O157 in the countryside is everyone’s problem. That means we should all take responsibility — individual residents and visitors, as well as farmers and government — according to experts…

Read the article

August 26, 2011 Posted by | Public Health | , , | Leave a comment

Bacterial Resistance to Antibiotics: The More They Resist, the More They Divide

These are Escherichia coli colonies growing on a petri dish. (Credit: Sílvia Mendonça)

From the 28 July 2011 Science Daily article

The number of multiresistant strains of bacteria in hospitals is increasing. Bacteria acquire resistance to antibiotics through mutations in their chromosomes and by incorporating new genes, either from the surrounding environment or from other bacteria. Now, a research team at the Portuguese CBA research (University of Lisbon) and the Instituto Gulbenkian de Ciência has shown that, surprisingly, when both mechanisms of resistance are playing out in the bacterium Escherichia coli (E. coli), its ability to survive and reproduce is increased.

Read article
Journal Reference:
Rui F. Silva, Sílvia C. M. Mendonça, Luís M. Carvalho, Ana M. Reis, Isabel Gordo, Sandra Trindade, Francisco Dionisio. Pervasive Sign Epistasis between Conjugative Plasmids and Drug-Resistance Chromosomal Mutations. PLoS Genetics, 2011; 7 (7): e1002181 DOI: 10.1371/journal.pgen.1002181

July 29, 2011 Posted by | Medical and Health Research News | , , | Leave a comment

Five food safety myths — debunked!

Five food safety myths — debunked!

From the Daily Need

By Anastacia Marx de Salcedo February 8, 2011

 

 

 

1. Food safety is worse than it used to be.

Food safety has actually improved since the mid-1990s when the Centers for Disease Control first began its national monitoring program, with net incidence of the major illnesses falling by 20 percent. On a disease-by-disease basis, that means 30 percent less campylobacter, 41 percent less toxin-producing E. coli and 10 percent less salmonella. In fact, the only increase — by 85 percent — has been in vibrio, contracted by eating raw shellfish. (You heard it, people, shuck and slurp and you’re on your own.) And even though the CDC recently tripled the number of major foodborne pathogens it monitors from 9 to 31, it reduced its estimate of annual illnesses from 76 to 48 million.

2. The biggest danger to your health comes from livestock feeding practices, food industry negligence and the terrorist threat to our food supply.

More than 90 percent* of foodborne illnesses occur within a vast, loosely organized network of rogue microbe breeders: restaurants! (about half of all outbreaks) and a motley assortment of workplaces, banquet facilities, caterers, churches, nursing homes, schools and others. Almost 60 percent of these — 5.5 million illnesses — are caused by norovirus, about which the CDC observes, “In many of these cases, sick food handlers were involved in the spread of the virus.” A 2004 study by the FDA found that 56 percent of fast food and 72 percent of full-service restaurant personnel did not wash their hands often or well enough. Ten viral particles with your soup, sir? (Or fork or menu or credit card?)

3. OMG! I’ve got salmonella! I’m going to DIE!

Just calm down, get plenty of rest and keep hydrated. Your risk of death isextremely small — half of one percent for salmonella, one tenth of one percent for campylobacter and half of one percent for even the most virulent variety of E. coli. In fact, the total annual number of deaths from foodborne illnesses is about 3,000, or the number killed by the flu in a very, very good year. (In a bad year, flu can kill up to 50,000 people.) As with influenza, most food-pathogen-related deaths are among the very old, the very young and the immunologically compromised. That guy whotestified before Congress that his mother died from eating contaminated peanut butter? Shirley Almer may have had a lot of sisu, Finnish for spunk, but she also had lung cancer and a brain tumor and was far more susceptible to infections, including the UTI she was hospitalized for when she contracted salmonella.

4. From now on, I’m scouring every tomato! Pressure-washing every pepper!

Go right ahead if it makes you feel in control — and to remove some pesticides and grit. But unless you’re plunging your produce in boiling water or immersing it in a 10 percent bleach solution, those little salmonella, campylobacter and E. coli bacteria are going to go right on doing the things organisms like to do — ingesting, reproducing, excreting. Speaking of which, most major foodborne illnesses are transmitted through feces — campylobacter: chickens; E. coli: cows; salmonella: the whole barnyard; norovirus: us — and some are perfectly normal residents of animal guts. They only cause mayhem when we insert them — via dirty food or hands — in places they shouldn’t be, e.g. our mouths.

5. Anyway, now that the Food Safety Modernization Act’s been signed into law, I don’t have to worry about this stuff, right?

Of course not! Faster recalls, more frequent inspection of food processing facilities, greater importer accountability and high-tech food-chain tracking are going to eradicate all foodborne illnesses…. Except for those 58% that come from norovirus and the other unknown percent — probably substantial — that are caused or exacerbated by risky food service practices such as cross-contamination through utensils, work surfaces and equipment; storage at improper temperatures; commingling of foodstuffs; and, of course, poor hygiene. What with 42% of our food budget spent on meals outside the home, you know what would have really made sense? A national safety-training program for food service workers.

February 10, 2011 Posted by | Health News Items | , , , | Leave a comment

Texas A&M research shows bacteria provide example of one of nature’s first immune systems

From the December 23, 2010 Eureka news release

COLLEGE STATION, Texas, Dec. 23, 2010—Studying how bacteria incorporate foreign DNA from invading viruses into their own regulatory processes, Thomas Wood, professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University, is uncovering the secrets of one of nature’s most primitive immune systems.

His findings, which appear in “Nature Communications,” a multidisciplinary publication dedicated to research in all areas of the biological, physical and chemical sciences, shed light on how bacteria have throughout the course of millions of years developed resistance to antibiotics by co-opting the DNA of their natural enemies—viruses.

The battle between bacteria and bacteria-eating viruses, Wood explains, has been going on for millions of years, with viruses attempting to replicate themselves by – in one approach – invading bacteria cells and integrating themselves into the chromosomes of the bacteria. When this happens a bacterium makes a copy of its chromosome, which includes the virus particle. The virus then can choose at a later time to replicate itself, killing the bacterium—similar to a ticking time bomb, Wood says.

However, things can go radically wrong for the virus because of random but abundant mutations that occur within the chromosome of the bacterium. Having already integrated itself into the bacterium’s chromosome, the virus is subject to mutation as well, and some of these mutations, Wood explains, render the virus unable to replicate and kill the bacterium.

With this new diverse blend of genetic material, Wood says, a bacterium not only overcomes the virus’ lethal intentions but also flourishes at a greater rate than similar bacteria that have not incorporated viral DNA.

“Over millions of years, this virus becomes a normal part of the bacterium,” Wood says. “It brings in new tricks, new genes, new proteins, new enzymes, new things that it can do. The bacterium learns how to do things from this.

“What we have found is that with this new viral DNA that has been trapped over millions of years in the chromosome, the cell has created a new immune system,” Wood notes. “It has developed new proteins that have enabled it to resists antibiotics and other harmful things that attempt to oxidize cells, such as hydrogen peroxide. These cells that have the new viral set of tricks don’t die or don’t die as rapidly.”

Understanding the significance of viral DNA to bacteria required Wood’s research team to delete all of the viral DNA on the chromosome of a bacterium, in this case bacteria from a strain of E. coli. Wood’s team, led by postdoctoral researcher Xiaoxue Wang, used what in a sense could be described as “enzymatic scissors” to “cut out” the nine viral patches, which amounted to precisely removing 166,000 nucleotides. Once the viral patches were successfully removed, the team examined how the bacterium cell changed. What they found was a dramatically increased sensitivity to antibiotics by the bacterium.

While Wood studied this effect in E. coli bacteria, he says similar processes have taken place on a massive, widespread scale, noting that viral DNA can be found in nearly all bacteria, with some strains possessing as much as 20 percent viral DNA within their chromosome.

“To put this into perspective, for some bacteria, one-fifth of their chromosome came from their enemy, and until our study, people had largely neglected to study that 20 percent of the chromosome,” Wood says. “This viral DNA had been believed to be silent and unimportant, not having much impact on the cell.

“Our study is the first to show that we need to look at all bacteria and look at their old viral particles to see how they are affecting the bacteria’s current ability to withstand things like antibiotics. If we can figure out how the cells are more resistant to antibiotics because of this additional DNA, we can perhaps make new, effective antibiotics.”

 

January 3, 2011 Posted by | Medical and Health Research News | , , , , , , | Leave a comment

The Costs of Food Born Illness and Related Information

From the Web page of the Partnership for Food Safety Education (PFSE)

Foodborne illness is much more than the “stomach flu”, and it is a serious health issue and economic burden for consumers. According to the Economic Research Service (ERS) of the USDA, each year $6.9 billion in costs are associated with five bacterial pathogens, CampylobacterSalmonellaListeria monocytogenesE. coli O157:H7, and E. coli non-O157:H7 STEC (2000). These costs are associated with medical expenses, lost productivity, and even death.The ERS estimates that the annual economic cost of salmonellosis—the illness caused by the Salmonella bacterium—is $2.65 billion (2009). This estimate is for all cases of salmonellosis, not just foodborne cases. The estimate includes medical costs due to illness, the cost (value) of time lost from work due to nonfatal illness, and the cost (value) of premature death.

The ERS estimates that the annual economic cost of illness caused by shiga toxin-producing E. coli (STEC O157) is $478 million (2009). This estimate is for all cases of STEC O157 disease, not just foodborne cases. The estimate includes medical costs due to illness, kidney dialysis and transplant costs, and the cost (value) of time lost from work due to nonfatal illness, and the cost (value) of premature death.

The ERS estimates that the annual economic cost of illness caused by Campylobacter, the most frequently isolated cause of foodborne diarrhea, is $1.2 billion. The estimate includes medical costs, lost productivity, and death due tocampylobacteriosis from food sources and costs associated Guillain-Barré syndrome (GBS), a form of paralysis.

Estimates for the cost of foodborne illness do not include other significant costs to both industry and government.

The Partnership for Food Safety Education is a collaboration of the US Depts of Health and Human Services, Education as well as leaders of food trade associations, consumer and public health organizations and the Association of Food and Drug Officials.

The PFSE  Web page includes links to

 

 

December 21, 2010 Posted by | Consumer Health, Consumer Safety, Educational Resources (High School/Early College(, Health Education (General Public), Public Health | , , , , , , , | Leave a comment

   

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