Methicillin-resistant Staphylococcus aureus (MRSA)

Posted by Dr. Steve Dudley on November 03 2008 11:52

Background

• Staphyloccocus aureus (Staph aureus) is a bacteria found in close to 30 percent of humans.
• Methicillin-resistant Staphylococcus aureus (MRSA) is a type of Staph aureus bacteria that can be found in the nasal passages and skin of up to 2.5 million people in the United States.
• MRSA is resistant to methicillin and in many cases to several other antibiotics.
• Although studies have found that 1-2 percent of the U.S. population carry MRSA, being a carrier of the bacteria does not necessarily mean that one will get sick.
• MRSA has been found in many animals, domestic (such as cats, dogs and horses) and wild (such as marine mammals, turtles and rabbits). MRSA also has been found in samples of meat including beef, veal, lamb, chicken, turkey, other fowl, game meats and pork. Furthermore, recent studies have found it in meat offered at retail.

How pork got involved

• MRSA has been prevalent in the human population for decades.
• Eighty percent of MRSA cases are healthcare associated. In the 90s it was first identified outside of healthcare facilities.
• It was first identified in pigs in Holland in 2005. Subsequently, it was found in pigs in Asia and North America, including in Canada and the United States.
• While the first studies for MRSA in North American pigs were conducted in 2007, it may be possible that it was there before, but it had never been identified.
• In the spring on 2008, research results from a Canadian study identified MRSA in pork products at retail.
• In Oct . 2008, an investigative reporting piece by a northwestern United States TV station (Washington, Idaho, Northern California) found MRSA in 3 of 97 samples of pork at retail.

What the pork industry is doing

• In the summer of 2007, the National Pork Board committed to work toward understanding the issue of MRSA and its implications to the U.S. consumer and the pork industry.
• Over $200,000 of industry funds have been used on scientific studies on MRSA. Industry research has focused on how MRSA affects pigs, people and pork.
• The industry’s position is that of understanding everything it can about MRSA and it will continue to invest significant amounts of resources in related research.
• From industry research and other available research, this is what has been found:

  • Pigs

    • While some pork production operations have a high number of pigs positive for MRSA, some operations have none.
    • Pigs sampled at packing plants in the United States indicate that levels of pigs carrying MRSA are similar to levels found in Europe and Canada.
    • The Centers for Disease Control and Prevention (CDC) has stated that having contact with pigs does not increase one’s chances of acquiring a MRSA infection.

  • People

    • National data suggest that approximately 2.5 million healthy people in the United States carry MRSA on their skin or in their n asal passage.
    • Being a carrier of MRSA does not necessarily mean one will become sick.
    • Additionally, encounters with carriers usually do not result in infection or clinical illness.

  • Pork

    • The CDC has stated that although MRSA has been found in retail meats, which could suggest a role of MRSA in foodborne trans mission, if this transmission occurs, it likely accounts for a very small proportion of human infections in the United States.
    • Furthermore, the Dutch Food Safety authority has stated that MRSA is not a food safety issue.
    • Preliminary research funded by the National Pork Board suggests that the levels of MRSA found in retail meat in the United States are similar to that found in Canada and the EU.
    • Although there is a theoretical risk of infection from handling contaminated meat, none has been proven.
    • MRSA has been found in retail meat, including beef, veal, lamb, chicken, turkey, other fowl, game meats and pork in some studies

Additional studies being funded by the pork industry include:

• Quantifying the amount of MRSA in pork
• Identifying the minimum safe cooking temperatures to inactivate the bacteria

This is what you can do now:

Recommend that all consumers follow Partnership for Food Safety Education’s Fight BAC!® guidelines for safe food handling. These are:

• Clean
• Separate
• Cook
• Chill
• Reinforce personal hygiene standards in food handlers (at all levels of the pork chain)