Wow, That’s Some Pig

WilburHeather Griffiths (5 PM Micro) enjoys my hyperbole about various microbiological menaces. She found an article from Consumer Reports about a gastrointestinally acquired species of Yersinia, a relative of the causative agent of Bubonic Plague. Here is what Heather found:

According to an upcoming Consumer Reports Study, (Read: sensationalist article with valid points) the latest reason to panic is Yersinia enterocolitica. Be advised: this article is not peer-reviewed, but it makes valid points when paired with information from the CDC.

According to the CDC, Yersinia enterocolitica is a Gram-negative bacillus that rarely causes disease in humans. Its virulence factors, adhesin and type III secretion system, play a role in attachment to human cells and apoptosis of macrophages and neutrophils. Species of Yersinia are found in various animal reservoirs: cattle, horses, sheep, rabbits, rodents, dogs, cats, and pigs. The infamous Yersinia pestis in rodents causes Bubonic plague.

Pigs are the main reservoir for Yersinia enterocolitica. Humans are infected with Y. enterocolitica by ingesting contaminated undercooked pork products, or by drinking contaminated pasteurized milk, as was the case in Allegheny County, PA last year. It may also be transmitted to infants by improper hand washing, especially when handling raw chitterlings (intestines) and picking up toys or pacifiers.

The symptoms of Y. enterocolitica infections mimic appendicitis: fever, abdominal pain, and diarrhea. Most symptoms resolve with proper rest and hydration. Some long-term effects may occur. Occasionally, joint pain may occur that lasts up to six months. Women are more likely to develop a rash on the legs and trunk called erythema nodosum. More complicated infections require antibiotics effective against Gram-negative bacteria, such as doxycycline, trimethoprim-sulfamethoxazole, aminoglycosides, or fluoroquinolones.

Diagnosis of Y. enterocolitica infection requires a positive stool specimen.  Since Y. enterocolitica infection occurs infrequently, contamination is not required to be reported to the CDC by the pork industry.  Y. enterocolitica infections are easily prevented by avoiding ingestion of raw pork (just say no to intestines), scrupulous hand washing and proper disposal of animal feces.

Consumer Reports tested 240 total samples of pork chops and ground pork from major labels and local brands. Major labels tested include Hormel, Smithfield, Roseland, and Nature’s Promise. Local brands tested include Giant, Wal-Mart, Wegmans, Weis, and Whole Foods.

Consumer Reports found 69% of the 240 products tested positive for Yersinia enterocolitica, 11% tested positive for Enterococcus, 7% tested positive for Staphylococcus aureus, as well as positive tests for Salmonella and Listeria. Out of 240 samples, 198 samples contained bacteria that were “resistant to antibiotics commonly used to treat people.” These antibiotics include amoxicillin, penicillin, tetracycline, and streptomycin.

This (somewhat misleading) data brings us to the focus of this article–antimicrobial-resistant bacteria in livestock. Prophylactic treatment of livestock causes antimicrobial-resistance. Consumer Reports urges subscribers to buy only clearly-labeled certified organic pork. As for prevention, Consumer Reports reiterates the food-handling recommendations from the CDC, and advocates for certified-organic pork.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on December 5, 2012, in Danger danger danger!, Guest Post, You are what you eat. Bookmark the permalink. Comments Off on Wow, That’s Some Pig.

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