Molecular characterisation of methicillin-resistant Staphylococcus pseudintermedius from dogs and the description of their SCCmec elements

Abstract In recent years an increasing number of methicillin-resistant S. pseudintermedius (MRSP) has been observed in both, healthy and clinically infected dogs. The aim of the study was the characterisation of MRSP isolates from clinical routine diagnostics of a German laboratory in order to assess the abundancy of resistance genes and SCC mec elements. 97 isolates from 96 dogs were analysed using microarrays detecting resistance genes and SCC mec -associated markers. All isolates harboured mecA and blaZ . Other abundant resistance markers (in >80% of isolates) included aacA-aphD, aphA3 and sat as well as erm (B). Tetracycline resistance genes ( tet (K), tet (M)) and cat also were common (in >20%). The vast majority (n = 59) of isolates carried SCC mec III elements. SCC mec IV and V elements were identified in 21 and 15 isolates, respectively. Irregular or pseudo-SCC mec elements were found in 2 isolates. The high degree of uniformity of hybridisation patterns of tested strains suggest that the majority of MRSP infections was caused by one single strain and comparison to previously published reports and sequences suggest that this was the ST71-SCC mec III strain that also predominates elsewhere in Western Europe.