Plagues,
Pestilences and Diseases
CDC Scientists find MRSA Superbug germ in supermarket meats
USA Today
MRSA, a bacteria resistant to common antibiotics, has been
discovered in supermarket meats, and the germ is apparently being
introduced by human food handlers, a new study reports.
The risk of becoming infected from the bacteria is especially high
if you have open cuts or sores on your hands or skin.
Although thorough cooking will kill the bacteria, consumers run
the risk of infection if they handle meats contaminated with the
germ, researchers said.
MRSA (methicillin-resistant Staphylococcus aureus) is common in
hospitals and nursing homes, where it can cause serious illness
and even death. And so-called "community-acquired MRSA" has become
a problem among some high school and college athletes who share
equipment; this type of MRSA appears as a skin infection and is
usually less serious, according to the U.S. Centers for Disease
Control and Prevention.
It's the community-acquired MRSA that was found in the meats, the
researchers said.
"MRSA has always been found in human patients, but we found this
in retail meat, so retail meat can be a reservoir of these bugs,"
said study lead researcher Yifan Zhang, an assistant professor in
the department of nutrition and food science at Wayne State
University in Detroit.
"When people handle food, they can get the bugs from the meat if
the meat is already contaminated," she explained.
The risk of becoming infected is especially high if you have open
cuts or sores on your hands or skin, Zhang added.
"When you handle food, especially if you have wounds on your
hands, wear gloves to protect yourself from getting MRSA
infection," she said.
The researchers found a human strain of MRSA in meats, so people
can also transfer the bacteria to meat, she added.
Contamination can occur if carriers of MRSA handle meat or if
there is MRSA in the environment, which might happen in meat
processing plants, Zhang added.
The report was published in the May 11 online edition of the U.S.
Centers for Disease Control and Prevention's journal Emerging
Infectious Diseases.
For the study, Zhang's team purchased 289 raw meat samples,
including 156 beef, 76 chicken and 57 turkey samples, from 30
grocery stores in Detroit from August 2009 through January 2010.
The researchers found that 22.5% of the samples were contaminated
with S. aureus and six samples tested positive for MRSA. Of the
six samples contaminated with MRSA, two were beef, three were
chicken and one was turkey, the researchers said.
The extent of MRSA contamination in meat varies by the type of
meat and where the meat was processed, Zhang said.
Zhang thinks that MRSA in meat results from contact by people
carrying the bacteria. Another recent study found that the strain
of MRSA in meat in the United States is not the strain found in
animals, she noted. That strain is found more commonly in Europe,
she added.
However, the animal strain of MRSA has been found in live pigs in
the United States, so it may appear in the food chain in the
future, the researchers added.
Dr. Marc Siegel, an associate professor of medicine at New York
University, said that "MRSA is a big problem and appears to be
invading our meat."
Siegel also believes that the MRSA contamination Zhang's group
found is most likely from infected people handling the meat.
Another factor is the overuse of antibiotics in the raising of
livestock. This, Siegel explained, could create
antibiotic-resistant animals that are more likely to be
susceptible to bacteria such as MRSA.
"The combination of the overuse of antibiotics and the fact that
MRSA is becoming more prominent in the human population explains
this," he said.
In addition to taking other precautions when handling meat, MRSA
is killed when the meat is cooked thoroughly, Siegel added.
Siegel also suggested washing plates or utensils used to prepare
food before using them again to eat. And, it is important to
disinfect counters that have come into contact with meats, he
advised.
These precautions would also kill off any other S. aureus, which
"we don't need in our meat either," Siegel said.
On a positive note, another report in the same journal issue finds
that efforts to reduce bacterial contamination of chicken from
campylobacteriosis have resulted in a 50% drop in what was an
epidemic in New Zealand.