Detection of Methicillin Resistant Staphylococcus aureus in Iberian pigs
Investigation published in Letters in Applied Microbiology
April 1st, 2012
Aims: Iberian pigs are bred in Spain for production of high-value dry-cured products, whose export volumes are increasing. Animals are typically reared outdoors, though indoor farming is becoming popular. We compared carriage of Methicillin Resistance Staphylococcus aureus (MRSA) in Iberian pigs, raised indoors and outdoors, with intensively farmed Standard White pigs. Methods and Results: From June 2007 to February 2008, 106 skin swabs were taken from Iberian pigs and 157 samples from Standard White pigs at slaughterhouses in Spain. We found that Iberian pigs carried MRSA, though with a significantly lower prevalence (30/106; 28%) than Standard White pigs (130/157; 83%). A higher prevalence of indoor Iberian pigs compared to animals reared under outdoor conditions was not significant, however all but one positive indoor Iberian pig samples were detected from one slaughterhouse. Overall, 16 different spa types were identified, with t011 predominating in all three animal populations. A subset of isolates was characterized by MLST. Most of these belonged to ST398. MRSA isolates from Iberian pigs presented a higher susceptibility to antibiotics than those isolated from Standard White pigs. Conclusions: Despite limited contact with humans, pigs raised outdoors are colonized by an MRSA population that genetically overlaps with that of intensively farmed pigs, though antimicrobial resistance is lower. Significance and impact of the study: To our knowledge, this is the first detection of MRSA in food animals raised in free-range conditions
Porrero MC., Wassenaar TM., Gomez S., Garcia M., Barcena C., Alvarez J., Saez-Llorente JL., Fernandez-Garayzabal JF., Moreno MA. and Dominguez L..
 | Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM). |
| Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM). |
| Molecular Microbiology and Genomics Consultants. | |
 | Departamento de Patología Animal. Facultad de Veterinaria. Universidad de Zaragoza (UNIZAR). |
 | Instituto de Investigación en Recursos Cinegéticos (IREC). Consejo Superior de Investigaciones Científicas (CSIC). Universidad de Castilla La Mancha (UCLM). Gobierno de Castilla-La Mancha (JCCM). |
 | Área de Ganadería. Ministerio de Agricultura, Alimentación y Medio Ambiente (MAGRAMA). |
