Scientists are beginning to detect antibiotic-resistant bacteria in pork, pigs and some veterinarians, raising the issue of whether these so-called superbugs might find a new route to infect farmworkers or even people who eat pork.
University of Minnesota veterinary public-health researchers last month reported they found the antibiotic-resistant bugs in 7.1% of 113 swine veterinarians tested. Public-health doctors at the University of Iowa found the same bacterial strains among 147 of 299 pigs tested with nasal swabs.
Perhaps of greatest concern, Ontario Veterinary College researcher Scott Weese also detected these bacteria in 10% of 212 samples of ground pork and pork chops collected in four Canadian provinces.
These particular strains of antibiotic-resistant bugs haven’t so far been shown to sicken patients, at least in North America. Three patients in Scotland were found to have the same bacterial strain, and there have been serious infections reported in the Netherlands related to these strains. Since an estimated 18,650 deaths a year in the U.S. are estimated to be caused by a range of antibiotic-resistant bacteria, researchers have encouraged U.S. and Canadian authorities to pay attention to the findings.
“It’s potentially relevant to the human population,” Dr. Weese said. “The question is whether it can cause problems among humans.” He cautions that such bugs in meat and pigs “are not an important source of disease at this point.”
In a medical-journal article last year, doctors at the Centers for Disease Control and Prevention estimated that there were 94,360 infections in a recent year in the U.S. from certain strains of antibiotic-resistant bacteria. Most were in patients who had recently been hospitalized or were in long-term care such as nursing homes, but there were also serious infections among people with no such histories. Often, the cases were skin infections, but others are nearly untreatable pneumonia or blood infections.
The concerns over superbugs in pigs and pork take place against a backdrop in which Congress is questioning whether the Bush administration is doing enough about food-borne illnesses. These include the recent cases of salmonella-related illness linked to fresh tomatoes, as well as other outbreaks of E. coli bacterial infections from ground beef. The Agriculture Department acknowledges it isn’t testing for the antibiotic-resistant bugs, officially called MRSA, which stands for methicillin-resistant Staphylococcus aureus.
That is understandable, in the view of Lyle Vogel, assistant executive vice president of the American Veterinary Medical Association. “This is something we cannot ignore, but it’s a resource issue,” he says. Compared with E. coli and salmonella infections, “it does not seem to rise to the top of the priority list.”
The National Pork Board, an industry trade group, is funding some of the research to evaluate how much of a concern it is for agriculture workers or the public. This includes the University of Minnesota’s work.