Prevalence of LA-MRSA in pigsties: analysis of factors influencing the (De)colonization process.

Professional pig husbandry is often associated with a more or less high load of LA-MRSA. Possible risk factors for LA-MRSA colonization in pig herds have already been identified in studies suggesting that housing conditions may affect LA-MRSA prevalence. In Europe, pigs are kept under variety of conditions. The aim of this study is to identify husbandry and housing condition factors that affect colonization with LA-MRSA. 78 pig farms were selected and assigned to three categories according to housing conditions: conventional, alternative and organic. Animal and surface samples were taken and examined for the presence of LA-MRSA at beginning and end of one fattening period per farm. Altogether, a significant (p < 0.05) decrease in colonization with LA-MRSA from beginning to end of the fattening periods in pigs and surfaces can be observed. Alternative farms showed a higher dynamic in the colonization. In organic farms, almost no colonization was found. Influencing housing condition factors that determine LA-MRSA status at the end of the fattening period are the number of pigs in the building, LA-MRSA status at the beginning of fattening period, material of the floor (straw bedding), strictness of black-white separation and antibiotic treatment during the fattening period. For pig farming in general, knowledge and measures to reduce the colonization with LA-MRSA would be important.