A brand spanking new paper in mBio describes how a clone of MRSA (the bacterium methicillin rensitive Staphylococcus aureus), known as ST398, long-associated with agriculture including pigs gained its methicillin and tetracylcine resistance. Surprise! It happened in the agricultural setting. Bloggysphere ST398 expert and co-author Tara Smith explains:

The findings throw the ST398 story a bit on its head. Instead of being a true pig strain, ST398 appears to have originated as a methicillin-susceptible human strain which was transferred into the pig population, picked up antibiotic resistance genes (including resistance to methicillin and tetracyclines), and then has been passed back to farmers as more resistant organisms.

So, I’m curious: how will Big Ag react? In my experience, they have argued about scientific uncertainty (just like Big Tobacco), saying we need more studies. Well, this is damn good evidence that antibiotic resistance and resistant strains evolved on the farm.

No doubt, they’ll argue that we need two or three more epidemics to make the case…

Related post: Katherine Harmon has more coverage of this.

Cited article: Lance B. Price, Marc Stegger, Henrik Hasman, Maliha Aziz, Jesper Larsen, Paal Skytt Andersen, Talima Pearson, Andrew E. Waters, Jeffrey T. Foster, James Schupp, John Gillece, Elizabeth Driebe, Cindy M. Liua, Burkhard Springer, Irena Zdovc, Antonio Battisti, Alessia Franco, Jacek Żmudzki, Stefan Schwarz, Patrick Butayej, Eric Jouy, Constanca Pomba, M. Concepción Porrero, Raymond Ruimy, Tara C. Smith, D. Ashley Robinson, J. Scott Weese, Carmen Sofia Arriola, Fangyou Yu, Frederic Laurent, Paul Keima,, Robert Skov, & Frank M. Aarestrup (2012). Staphylococcus aureus CC398: Host Adaptation and Emergence of Methicillin Resistance in Livestock mBio, 3 (1), 305-311 : 10.1128/mBio.00305-11