The researchers, including USDA Agricultural Research Service (ARS) animal scientist Thomas S. Edrington, reported how the E. coli sense a key chemical that plays a critical role in allowing the bacteria to colonize inside the cattle’s gastrointestinal (GI) tract.

To proliferate, E. coli express genes differently based on their environment, such as outside the cattle host, inside the cattle rumen, or even at the end of the cattle GI tract. Having a better understanding of when, why and how these bacteria colonize could lead to practical applications in the future, according to Edrington.

The researchers showed that “quorum sensing” chemicals called acyl-homoserine lactones (AHLs), which are produced by other bacteria, are present within the bovine rumen but absent in other areas of the cattle GI tract. AHLs are important because E. coli harbor a regulator, called SdiA, which senses these AHLs and then prompts the E. coli to attach and colonize.

The research suggests that limiting production of the SdiA chemical, or blocking bacterial reception of the AHLs, may eventually lead to new strategies for keeping E. coli from attaching inside the animal.

The study, published in the Proceedings of the National Academy of Sciences, was conducted at the University of Idaho, Moscow, Idaho, campus. It involved researchers from several universities and was headed by Vanessa Sperandio, who is with the University of Texas Southwestern Medical Center, in Dallas.

Mary Clifton with the Ohio Department of Health told NBC4-TV in Columbus, Ohio, that there is a push to get more rapid testing. The problem is that there is not an improved standard test yet to do rapid testing. The Ohio State research report said that better methods need to be in place to protect lakes from being contaminated in the first place. Shiga toxin-producing E. coli bacteria grow in the guts of cattle and other animals. The animals shed the pathogen  in their feces and it can be washed into waterways during rains.

The Centers for Disease Control and Prevention has published its latest set of data on foodborne disease outbreaks submitted from all states and territories. The CDC Surveillance for Foodborne Diseases Outbreaks Report summarizes epidemiologic data for the 1,097 reported outbreaks occurring during 2007 (the most recent finalized data), which resulted in 21,244 cases of foodborne illness and 18 deaths.

 Among the 497 foodborne outbreaks with a laboratory-confirmed single etiologic agent reported, 40 were shiga toxin-producing E. coli outbreaks, primarily E. coli O157:H7. Coupled with two more suspected E. coli outbreaks, the E. coli classification accounted for 6 percent of 2007 outbreaks.

The 2007 surveillance number was much higher than the mean established from 2002-2006. In that period, the mean number of shiga toxin-producing E. coli outbreaks was 28 per year, or 2 percent of the total outbreaks.

In terms of illnesses, the 2007 report also was higher.  In 2007,  CDC and state health departments tracked 603 confirmed and suspected shiga-toxin E. coli illnesses. That was up from the 2002-2006 mean number of 375 E. coli illnesses per year.

It is important to note when reviewing the foodborne disease surveillance report that the actual numbers of outbreaks and illnesses in the U.S. is much higher than those confirmed by public health scientists and laboratories.

Researcher Dr. Prysor Williams said: “We are taking small samples of blood and saliva and looking for antibodies in the samples. That will tell us if that individual has been exposed to 0157. If antibodies are present it shows that that individual has a degree of immunity because all the volunteers are not patients.”

The story reports that the study’s findings could help in the search for an E. coli vaccine, and that repeated exposure over a long period of time may be protecting these farmers from the otherwise harmful pathogen. The Scotsman story reports that the Grampain region is said to have one of the highest E. coli infection rates in the world, and results of the study suggest a much higher rate of antibodies among that region’s population. According to the story:

Rates of E coli 0157 in Scotland are higher than the rest of the UK. Last year, there were 4.6 cases per 100,000 people in Scotland, compared with fewer than two per 100,000 in England. In Grampian there were 11.1 cases per 100,000…The reasons for the higher rates in Scotland remain unclear.

The research, published August 1 by the journal Applied and Environmental Microbiology, was conducted by the USDA’s Agricultural Research Service.

E. coli 0157:H7 is a dangerous foodborne pathogen in humans that grows benignly in cattle.

It is common to test cattle feces to determine if any individual animal is shedding the bacteria, but scientists are seeking more information about where in the cattle gastrintestinal tract the E. coli can be found. The information is needed for the purpose of fighting the bug.

The research team found E. coli O157:H7 in samples from the mouth, pharynx, tonsils, lymph nodes, esophagus, all four sections of the stomach, and the small and large intestines, though the specific locations of positive cultures varied between animals.

“Although 31 percent of the animals were culture positive for E. coli O157:H7 somewhere along the intestinal tract, only 26 percent of those were fecal-culture positive. These data suggest that fecal shedding underestimated E. coli O157:H7 prevalence in the beef cattle gut and identified potential intervention sites,” the researchers concluded.

In short, fecal shedding underestimated E. coli O157:H7.

One presentation, “Flour Food Safety: The Changing Landscape — Escherichia coli O157:H7,” was given by representatives from Cargill, Nestle and ConAgra and outlined how the industry is reexamining flour as a potential source for E. coli contamination in food. The importance of this issue is highlighted by last year’s E. coli outbreak associated with Nestle Tollhouse raw cookie dough that sickened roughly 75 people in multiple states. According to and IAFP summary of the presentation:

“Flour has been viewed as a raw agricultural product for years; but with a recent outbreak involving consumption of an uncooked product containing flour, regulators and industry are re-examining whether flour should be treated as a RTE ingredient in some foods that may be consumed uncooked by the consumer. This mini-symposium will examine the history of flour and what industry knows about the microbiology of this product during production, harvesting and milling; the regulatory perceptions of flour as a potential vehicle of pathogens; the transformation of microbiological criteria associated with flour and the verification testing required to gauge compliance with the new criteria; and one solution available to deliver RTE flour as an ingredient.”

Another piece of research included at the conference comes from researchers at the Silliker, Inc., Food Science Center in South Holland, Illinois, and focuses on validating testing methodologies for raw cookie dough and its ingredients.

The U.S. Centers for Disease Control and Prevention (CDC) estimate that non-O157 STEC bacteria are responsible for 36,000 illnesses, 1,000 hospitalizations and 30 deaths annually.

In recent years, they have become a growing concern as agents of foodborne illness. In fact, USDA has been studying the possibility of expanding  its definition of “adulterated meat” to include meat that is contaminated with non-O157 STEC E. coli.

 According to the CDC, about 70 percent of non-O157 STEC isolated from humans fall into six serogroups, which are (in order of frequency): O26, O103, O111, O121, O45, and O145.   STEC that are known to cause human illness are sometimes called enterohemorrhagic E. coli (EHEC).

Whatever the serotype, if a bacterium is making Shiga toxins in the gastrointestinal tract of an infected individual, that person is at risk for developing hemorrhagic colitis and life-threatening HUS, or hemolytic uremic syndrome.

“The USDA continually looks for opportunities to collaborate in ways that will expedite research to assist regulatory agencies and move technologies into the marketplace. This collaborative project to develop a discriminating STEC test is a good fit with our mission,”  Pina Fratamico, USDA research microbiologist said in a press release.

During 2007, researchers tested 127 patients infected with E. coli that appeared resistant to cephalosporin and fluoroquinolone antibiotics. Of those cases, 54 were shown to be from this new strain, E. coli ST131.

“If this strain gains one additional resistance gene, it will become almost untreatable and will be a true superbug, which is a very concerning scenario,” Johnson said. he went on to tell local news sources that, “Fortunately, there’s still one big class of drugs that [E. coli ST131 is] so far universally susceptible to,” but that those drugs are “our last line of defense.”

More research into new antibiotics, plus exercising caution when using antibiotics, are two key elements needed to address this concern, according to health experts.

Sources:

http://www.startribune.com/lifestyle/health/99668604.html?page=2&c=y

http://www.msnbc.msn.com/id/38495130/ns/health-infectious_diseases/

The enteric infections caused by these pathogens are dependent on whether the bacteria are able to colonize in the intestine. Research from a Brazilian university is helping to better understand the variety of “strategies” these pathogens use to multiply inside their hosts and infect them. According to the research:

“Diarrhea-causing pathogens employ a variety of sophisticated strategies to colonize the intestinal epithelium [tissue lining the intestine].” In essence, ingested pathogens have evolved the abilities to:

1. Resist many of the host’s defenses such as stomach acidity, peristalsis, mucosal cell exfoliation, intestinal mucins, and bacteriocins
2. Adhere to intestinal epithelia (tissue).
3. Ultimately colonize that tissue.

Sometimes that colonization involves cellular invasion. When that happens, the bacteria can spread to other tissues in the host’s body. According to the research, the pathogens attack cells in the host’s body. “The host cell, in turn, defends itself against infection by initiating an inflammatory response and by altering the intestinal fluid balance in order to extrude the unwanted bacteria, thus causing diarrhea.” Therefore, whether the infection is “successful” depends upon complex interactions between the bacteria and the host cells. The bacteria’s mission, basically, is to exploit cell machinery for their own benefit.

Source:

http://www.gutpathogens.com/content/2/1/8

In response, Ms. Kendall provided the following salsa and guacamole FAQ: