Prevalence of toxin-producing strains and antimicrobial resistance in isolates of Staphylococcus hyicus from pigs with exudative epidermitis and from healthy pigs

Sammanfattning: Virulent strains of Staphylococcus hyicus produce exfoliative toxins and cause a potentially fatal skin disease in piglets known as exudative epidermitis. Vaccines and antimicrobials are used to control the disease. Antimicrobial resistance and the prevalence of several different toxin genes and toxigenic strains make it problematic. The aim of this literature study was to identify potential differences between countries and between healthy and diseased pigs regarding antimicrobial resistance and toxin-producing strains. Great differences could influence vaccine production, treatment strategies and surveillance programs. The prevalence of virulent strains were much higher in diseased pig isolates but were not uncommon among healthy pigs. No evidence for differences in the distribution of toxin genes between healthy and diseased pigs was observed but differences between countries were obvious. Some toxin genes were found to be dominant in certain countries. Differences in resistance patterns were seen between healthy and diseased pig as well as between countries but the antimicrobials with the highest resistance rates were almost the same in all observed countries. These findings show the importance of national and outbreak-related identification of the disease-causing strains to ensure that the most effective antimicrobial is used and that vaccines are produced from the right strains. More research is needed to follow the development but also to investigate why some pigs stay healthy despite carrying toxin-producing strains. There might be natural factors involved that could be used to prevent the disease and in turn decrease the need for antimicrobials in the future.