When it comes to methicillin-resistant Staphylococcus pseudintermedius (MRSP), resistance is increasing and it could signal new therapeutic challenges for veterinarians. The infection rates in human hospitals have been well-documented for methicillin-resistant Staphylococcus aureus (MRSA), but new data is suggesting MRSP may emerge as a similar threat to dogs, but without the same zoonotic potential to people. A study published in the Journal of Antimicrobial Chemotherapy (Perreten V, et al.) in late March suggests that two major clonal MRSP lineages "have disseminated in Europe and North America. Regardless of their geographical or clonal origin, the isolates displayed resistance to the major classes of antibiotics used in veterinary medicine and thus infections caused by MRSP isolates represent a serious therapeutic challenge." How serious? These isolates are showing resistance to many popular antibiotics including: trimethoprim (90.3 percent), gentamicin/kanamycin (88.3 percent), kanamycin (90.3 percent) streptomycin (90.3 percent), streptothrycin (90.3 percent), macrolides and/or lincosamides (89.3 percent), fluoroquinolones (87.4 percent), tetracycline (69.9 percent), chloramphenicol (57.3 percent) and rifampicin (1.9 percent).