Better Non-0157:H7 E. coli Test is in the Works
USDA is collaborating with DuPont Qualicon to develop a more effective test for the six most common non-0157:H7 shiga toxin-producing E. coli (STEC)
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.
Drug-Resistant E. coli Strain Emerging, Research Shows
A new strain of drug-resistant E. coli poses an emerging health concern, according to a study to be published this week in the journal of Clinical Infectious Diseases, led by Dr. James Johnson of the Minneapolis VA Medical Center. Cases of this strain, E. coli ST131, have been reported across the United States and in several countries, researchers say.
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/
E. coli, Shigella and Salmonella Infections: How They Spread
The strains of E. coli, Shigella and Salmonella that cause illness in humans are what are called enteropathogenic bacteria. Pathogenic meaning they cause harmful infectious diseases and enteric refers to the fact that the infections they cause are in the intestine.
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:
- Resist many of the host’s defenses such as stomach acidity, peristalsis, mucosal cell exfoliation, intestinal mucins, and bacteriocins
- Adhere to intestinal epithelia (tissue).
- 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
Salsa and Guacamole Can Be Safe Reports CDC Epidemiologist
A couple of weeks ago Magdalena Kendall, an epidemiologist with the CDC, and her colleagues presented research on foodborne outbreaks linked to salsa and guacamole. The researchers found that between 1998 and 2008, nearly 1 of every 25 outbreaks associated with restaurants or delis may have been caused by contaminated salsa or guacamole. This shocking statistic resulted in a flood of questions from scared consumers.
In response, Ms. Kendall provided the following salsa and guacamole FAQ:
What kinds of illnesses were associated with these outbreaks?
The most common infection was norovirus, followed by Salmonella, Shigella, E. coli, and other less common germs, which can all cause diarrhea.
Did your research show what contributed to these outbreaks?
Not in all cases, but there were some important clues. In 30 percent of the outbreaks, local investigators reported that the salsa or guacamole wasn’t stored or refrigerated properly. In another 20 percent, the investigators reported that food workers were the likely source of the contamination. In some cases, ingredients may have been contaminated before arriving in a kitchen.
Do you know which specific ingredients were contaminated?
We usually don’t know which ingredients were contaminated. But we do know that salsa and guacamole often contain diced raw produce, such as hot peppers, tomatoes, and cilantro. These ingredients have been implicated in past outbreaks.
Is there anything else about salsa or guacamole that makes it particularly likely to become contaminated?
Germs may grow to levels that can cause sickness if these foods are not prepared or stored safely in restaurants and homes. Also, salsa and guacamole are often made in large batches at restaurants, so even a small amount of contamination can affect many servings.
What about salsa that you buy at the store?
These outbreaks were not caused by commercially prepared (jarred) salsas that you would buy in a grocery store. Jarred salsas are usually heated to kill germs that may be present. Instead, most of the salsas we studied were freshly prepared.
Is homemade salsa or guacamole safe?
That depends on whether you follow these food safety rules:
- Before and after preparing food, wash your hands for 20 seconds with warm water and soap.
- Wash the ingredients thoroughly under running water. That includes ingredients that you plan to peel, such as avocados.
- Make sure that knives, cutting boards, containers, and other kitchen surfaces are clean.
- Keep the salsa or guacamole refrigerated until you serve it. Do not leave it out of the refrigerator for more than 2 hours. If the temperature is above 90 degrees, do not leave it out for more than 1 hour.
If you were eating out, what would you do to make sure these foods are safe?
If I were worried about the food safety practices in a restaurant, I would ask to see health department inspection results. I might also ask whether the restaurant has a manager who is certified in food safety. Some counties or states require this.
E. coli is Among the Threats in Salsa, Guacamole
Recent advice from a noted epidemiologist to be wary of food poisoning in salsa and guacamole seems acutely profound in the wake of news in Iowa that an outbreak of Salmonella is tied to salsa, guacamole and tamales made by La Reyna restaurant in Iowa City.
Twenty-five people are sick in the Iowa outbreak, which is connected to sales of the restaurant-made items at farmers’ markets and other locations in eastern Iowa.
Dr. Magdalena Kendall, surveillance epidemiologist with the Centers for Disease Control and Prevention said a recent research project showed that nearly one of every 25 outbreaks associated with restaurants or delis between 1998 and 2008 may have been caused by contaminated salsa or guacamole.
Dr. Kendall said the most common infection was norovirus, followed by Salmonella, Shigella, E. coli, and other less common germs, which can all cause diarrhea.
E. coli infections can be particulary dangerous because up to 15 percent of cases lead to hemolytic uremic syndrome (HUS), the leading cause of kidney failure in children.
Dr. Kendall’s research found that in 30 percent of the outbreaks, local investigators reported that the salsa or guacamole wasn’t stored or refrigerated properly. In another 20 percent, the investigators reported that food workers were the likely source of the contamination. In some cases, ingredients may have been contaminated before arriving in a kitchen.
Also, salsa and guacamole are often made in large batches at restaurants, so even a small amount of contamination can affect many servings.
Latest CDC Roundup Indicates 5,309 E. coli Cases for 2008
E. coli O157:H7 has been a nationally notifiable disease with the Centers for Disease Control and Prevention (CDC) since 1994. National surveillance for all Shiga toxin-producing E. coli (STEC) began in 2001.
This week, the CDC released its latest annual Summary of Notifiable Diseases and it covers calendar year 2008.
According to the report, there was a total in 2008 of 5,309 U.S. confirmed cases of Shiga toxin-producing E. coli. The report did not break down the total by serotype, but O157:H7 is dominant. The report does not analyze growth patterns, but when comparing to totals in the two previous years there has been an upward trend in total cases.
In 2006, the total number of U.S. confirmed cases of Shiga toxin-producing E. coli was 4,432. One year later, the total increased to 4,847.
Normally, cases spike in warmer months and drop off in early winter. That was the case in 2008 — as the breakdown showed 843 cases for August and 668 cases for July — the two highest monthly totals for the year. The lowest monthly total was 147 in February 2008.
You can see CDC’s 2008 Summary of Notifiable Diseases in its entirety on the CDC website.
Healthy cattle, which harbor the organism in their intestines, are the main animal reservoir of STEC. Most reported outbreaks are caused by contaminated food or water. During 2004, a substantial decline in reported O157:H7 STEC cases led to an incidence rate that met the Healthy People 2010 goal of less than 1 case per 100,000 population; since then, the incidence has increased.
