Resumen de Selected highlights from other journals: Three genetic steps to multidrug-resistant Staphylococcus pseudintermedius

A.J. McCarthy, E.M. Harrison, K. Stanczak-Mrozek, B. Leggett, A. Waller

• THE continuing emergence of new multidrug-resistant (MDR) pathogens remains one of the biggest threats to public and animal health. Meticillin-resistant Staphylococcus pseudintermedius (MRSP), first recognised in North America in 1999, has become rapidly established as a MDR small animal pathogen worldwide, emerging in the UK since 2007. It is not clear how and why this previously widely susceptible pathogen, mostly associated with canine pyoderma and otitis, was able to develop multidrug-resistance so rapidly. This study investigated this question by establishing the genetic basis of multidrug-resistance in MRSP using whole genome sequencing.

  Twelve clinical S pseudintermedius isolates from dogs with varying antimicrobial resistance profiles (meticillin-susceptible S pseudintermedius [MSSP], MDR-MSSP, MRSP and MDR-MRSP) were sequenced. Isolates were classed as MDR if they were resistant to antimicrobial agents in three or more antimicrobial classes and verified as meticillin-resistant if they carried mecA, the gene conferring broad β-lactam antibiotic resistance in staphylococci. Comparative genomics confirmed that all MRSP isolates carried mecA on a staphylococcal cassette chromosome (SCC), a large mobile genetic element similar to that found in the human hospital …