Friday, 7 September 2012

Antimicrobial resistance of Staphylococcus aureus acquired by pig farmers from pigs

This Swiss research confirms the dangers to farmers (and veterinarians) from Pig MRSA,

The quite extraordinary absence of multidrug resistant MRSA st398 et al from Britain’s pigs, pig farmers and veterinarians would be one of the wonders of the world, if it was true.

Abstract here

Published ahead of print 7 September 2012, doi: 10.1128/​AEM.01902-12

Antimicrobial resistance of Staphylococcus aureus acquired by pig farmers from pigs

1.       Anne Oppliger1, 
2.       Philippe Moreillon2, 
3.       Nicole Charrière1,
4.       Marlyse Giddey2, 
5.       Delphine Morisset2 and 
6.       Olga Sakwinska2,*
+Author Affiliations
1.       1Institut universitaire romand de Santé au Travail (Institute for Work and Health), University of Lausanne and Geneva, rue du Bugnon 21, CH-1011 Lausanne, Switzerland
2.       2Department of Fundamental Microbiology, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland


Carriage of animal-associated MRSA CC398 is common among pig farmers. This study was conducted to investigate: 1) whether pig farmers are colonized with pig-specific S. aureus genotypes different than CC398, and 2) survey antimicrobial resistance of S. aureus isolates from pigs and pig farmers. Forty-eight S. aureus isolates from pig farmers and veterinarians and 130 isolates from pigs collected in Western Switzerland were genotyped by spa-typing and amplified fragment length polymorphism (AFLP). Antimicrobial resistance profiles were determined for representative sample of the isolates. Obtained earlier data on healthy S. aureus carriers without exposure to agriculture were used for comparison. The genotype composition of S. aureus isolates from pig farmers and veterinarians was similar to isolates from pigs with predominant AFLP Clusters CC398, CC9 and CC49. The resistance to tetracycline and macrolides (clarithromycin) was common among the isolates from farmers and veterinarians (52% and 21%, respectively), and similar to resistance levels in isolates from pigs (39% and 23%, respectively). This was in contrast to isolates from persons without contact with agriculture, where no (0/128) isolates were resistant to tetracycline and 3% of isolates were resistant to clarithromycin. MRSA CC398 was isolated from pigs (n=11) and pig farmers (n=5). These data imply that zoonotic transmission of multidrug resistant S. aureus from pigs to farmers is frequent, and well-known MRSA transmission merely represents a tip of an iceberg of this phenomenon. We speculate that relatively low frequency of MRSA isolation is related to lower antimicrobial use in Switzerland compared to e.g. the Netherlands.