MRSA superbug in US Factory Farm Operations

Researcher Tara C. Smith has just published a study in PubMed Central, a peer-reviewed journal, linking Methicillin-resistant Staphylococcus aureus (MRSA) to swine in Confined Animal Feed Operations (CAFOs), or factory farming facilities. This potentially fatal Staph bacterium is resistant to certain antibiotics, which include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin.

Although previous studies linking MRSA to swine and swine workers have been conducted in other countries, Ms. Smith's study, albeit small in size, is the first to be conducted in the U.S. The Iowa State researcher and her team found MRSA strain ST398 present in 45% of swine workers and 49% of swine at production facilities, housing approximately 87,000 live animals in Iowa and Illinois.

Factory farming operations confine a large number of animals to relatively small areas. These operations require both antibiotics and pesticides to reduce the spread of disease and pestilence. An excessive reliance on antibiotics can result in the incubation of virulent, resistant bacterial strains. A similar phenomenon occurs in hospitals, another area that is heavily-antibiotic reliant.

In March 2008, in a presentation to the International Conference on Emerging Infectious Diseases, Canadian researcher Dr. David Weese reported that 10 per cent of pork chops and ground pork samples from four provinces tested positive for MRSA. An expert on zoonoses, the pathogens that are transmitted between people and animals, Dr. Weese said that proper cooking would kill the bacteria on pork. However, he wondered about meat handlers who may come into contact with MRSA on the surface of meat.

MRSA infections were once mainly limited to hospitals, but in recent years, there have been reports of people with the infection who have not been in hospital or taken antibiotics. According to the Center for Disease Control, some 94,360 people developed a serious MRSA infection, which resulted in 18,650 deaths in 2005. The incidence of MRSA is on the rise in the U.S., and this bacterium is now recognized as a major community-acquired pathogen.