Methicillin resistance in Staphylococcus pseudintermedius encoded within novel staphylococcal cassette chromosome mec (SCCmec) variants.

BACKGROUND

Staphylococcus pseudintermedius is a common opportunistic pathogen of companion dogs and an occasional human pathogen. Treatment is hampered by antimicrobial resistance including methicillin resistance encoded by mecA within the mobile genetic element SCCmec.

OBJECTIVES

SCCmec elements are diverse, especially in non-Staphyloccocus aureus staphylococci, and novel variants are likely to be present in S. pseudintermedius. The aim was to characterize the SCCmec elements found in four canine clinical isolates of S. pseudintermedius.

MATERIAL AND METHODS

Isolates were whole-genome sequenced and SCCmec elements were assembled, annotated and compared to known SCCmec types.

RESULTS AND DISCUSSION

Two novel SSCmec are present in these isolates. SCCmec7017-61515 is characterized by a novel combination of a Class A mec gene complex and a type 5 ccr previously only described in composite SCCmec elements. The other three isolates share a novel composite SCCmec with features of SCCmec types IV and VI.

CONCLUSIONS

S. pseudintermedius is a reservoir of novel SSCmec elements that has implications for understanding antimicrobial resistant in veterinary and human medicine.