High Frequency of Multiresistant Coagulase-Positive <em>Staphylococcus aureus</em> Found in Slaughter Pigs in Uruguay

by 5m Editor
26 October 2011, at 12:00am

Although no methicillin-resistant S. aureus were detected, all the coagulase-positive S. aureus found in slaughter pigs in Uruguay were resistant to three or more classes of antimicrobials, say researchers based in Germany and Finland, which they linked to the over-use of antimicrobials in pig production.

Staphylococcus aureus is a hazard to human health since they can cause infections and food poisoning. Antimicrobial resistant strains render the treatment of infections problematic and contribute to the spread of antimicrobial resistance. In their paper published in the journal, Foodborne Pathogens and Disease, Cornelia Meyer of Ludwig-Maximilian-University in Munich, Germany and co-authors at Finland's Helsinki University say that these bacteria are therefore of great public concern.

Their study determined the resistance pattern of coagulase-positive S. aureus (CPSA) isolated from nasal swabs of 100 slaughter pigs from one farm in Uruguay. Out of 69 animals, 71 CPSA were collected. Minimum inhibitory concentrations of 20 antimicrobials were determined using the broth microdilution method in accordance with CLSI recommendations.

No methicillin-resistant S. aureus were detected. All CPSA were resistant to three or more classes of antimicrobials (i.e. multi-resistant), whereby all CPSA were resistant to spectinomycin. Most of the isolates (46 per cent) were resistant to six classes of antimicrobials.

Almost all isolates were resistant to penicillin (99 per cent), ampicillin (99 per cent), gentamicin (96 per cent), tetracycline (90 per cent), and tilmicosin (87 per cent). Very high resistance rates were observed against erythromycin (77 per cent) and clindamycin (70 per cent). High resistance was observed against tiamulin (40 per cent), enrofloxacin (31 per cent) and florfenicol (23 per cent) and low resistance was observed against amoxicillin/clavulanic acid (four per cent). All CPSA isolates were mecA negative.

Meyer and co-authors conclude that the results of their study could be related to an overuse of antimicrobials in pig production and should encourage veterinarians and pig holders to practice a controlled administration of chemotherapeutics in pig husbandry.


Meyer C., M. Fredriksson-Ahomaa, E. Stüber, S. Thiel and E. Märtlbauer. 2011. High frequency of multiresistant coagulase-positive Staphylococcus aureus found in slaughter pigs in Uruguay. Foodborne Pathogens and Disease. -Not available-, ahead of print. doi:10.1089/fpd.2011.0973

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October 2011