Washing sows (n=12 per herd) on four Belgian pig farms positive for methicillin-resistant Staphylococcus aureus (MRSA) had no significant effect on MRSA status of the sow’s skin (P=0.32) or nares (nostrils; P=1.00). In 64 per cent of cases, the same strain was detected before and after washing.

These were the findings of a study by Marijke Verhegghe from Belgium's Institute for Agricultural and Fisheries Research and co-authors there and at Ghent University, the Department of Bacterial Diseases and the Catholic University College of Southwest-Flanders.

In their paper in Journal of Swine Health and Production, they explain that in 2005, a new MRSA type was isolated from pigs and pig farmers and that this livestock-associated MRSA (LA-MRSA) is now found almost worldwide in livestock, most often in swine.

Generally, colonised animals show no signs of disease but are considered a potential source of MRSA for the human population. Other researchers have found that, on infected sow farms, piglets are likely to be infected with LA-MRSA after contact with the sows, the environment, other piglets, and animal-care attendants and that the sow’s MRSA status at farrowing significantly affects the piglet’s MRSA status.

Council Directive 2008/120/EC of the European Union states that pregnant sows and gilts must be thoroughly cleaned when placed in farrowing crates, which results in a clean sow that can be housed in the cleaned farrowing barn.

The Belgian researchers therefore set out to determine whether washing sows before or upon entry to the farrow house would impact the number or strains of presence of MRSA on the sow’s skin.

Reference

Verhegghe M., F. Crombé, I. De Man, F. Haesebrouck, P. Butaye, M. Heyndrickx and G. Rasschaert. 2103. Preliminary study of the effect of sow washing, as performed on the farm, on livestock-associated methicillin-resistant Staphylococcus aureus skin status and strain diversity. J. Swine Health Prod. 2013;21(6):313–318.

February 2014