Diagnostic value of phage typing, antibiogram typing, and plasmid profiling of Staphylococcus hyicus from piglets with exudative epidermitis.

A total of 989 isolates of S. hyicus were recovered from the skin of 103 piglets (9.6 isolates per piglet) with exudative epidermitis (EE), and phage typed. Phage patterns of 806 typable isolates (81%) could be divided into 44 distinct phage types. From 1 to 6 different phage types were found on individual piglets, with an average of 1.9 phage type per piglet. Antibiogram patterns of 384 isolates from 40 randomly selected piglets with EE showed a mean of 2.3 different antibiograms per investigated piglet, ranging from 1 to 6 antibiograms per piglet. Plasmid profiles of 248 S. hyicus isolates from 25 randomly selected piglets showed an average of 2.8 different plasmid profiles per piglet. Seven EE outbreaks in pig herds vaccinated with autogenous vaccine were investigated. In all these herds, strains recovered from the present outbreak differed by two or more type markers to the strains from the previous outbreak used for production of the autogenous vaccine. This finding suggest, that lack of protection might be due to the presence of other virulent types in the investigated herd than those used for production of autogenous vaccine.