Weese's news, tucked in at the end of a comprehensive presentation on MRSA and animals: Analysis of 212 raw pork products sold in four Canadian provinces reveals an average rate of MRSA contamination of more than 9%.
This shouldn't be surprising: Research by Weese and others has been revealing a complex and not well-understood interplay of infection between pigs and nearby humans.
- A 2005 French paper reported a rate of resistant-staph nasal colonization in pig farmers that was twice as high as among human controls; 57% of the isolates from the farmers were identical to nasal isolates in pigs.
- Last June, a Dutch study found 39% of pigs in nine major slaughterhouses in the Netherlands carried an identical novel MRSA strain.
- In December, two studies filled out the picture. A Dutch study reported the prevalence of that novel MRSA strain (dubbed ST 398 and first found in a human in 2003) has risen to more than 21% of all MRSA isolates in the country. A Canadian study (with Weese as senior author), published online ahead-of-print, found MRSA colonization rates of 25% among Ontario pigs and 20% among pig farmers, with most of them sharing the ST 398 strain but some possessing the CA-MRSA strain USA100.
- A Dutch study in January (first author Engeline van Duijkeren, who did the S. intermedius study from a few posts ago) found that pigs were colonized with MRSA on a variety of types of farms, such as ones that birth pigs and ones that raise them to slaughtering weight.
- And just to erase any doubts, several Dutch studies have established that the ST 398 strain causes human disease: endocarditis, mastitis, severe hospital-acquired pneumonia and bloodstream infection.
"People don’t tend to handle pork like it is biohazardous, unlike chicken. So there may be a theoretical concern that pork could be a vehicle of methicillin resistance colonization — but it is way too early to say anything about that."But if you're not already handling raw meat in a careful manner (sterilizing cutting boards, avoiding cross-contamination), it might not be too early to start.