Is there a difference between resistant and nonresistant strains?
What they did
In a retrospective case-control study, researchers compared clinically apparent methicillin-resistant Staphylococcus pseudintermedius (MRSP) and methicillin-susceptible S. pseudintermedius (MSSP) infections among dogs from June 2007 to October 2009. Overall, 56 case dogs with an MRSP infection were identified, and each was matched with two control dogs with an MSSP infection (one diagnosed immediately before the MRSP case and one immediately after). Pyoderma and otitis accounted for most of the infections.
What they found
Dogs that had received antimicrobial therapy within 30 days before diagnosis were nine times more likely to have an MRSP infection vs. an MSSP infection. Mortality rate was similar between the two groups, suggesting that the MRSP infection was no more pathogenic than the MSSP infection if treated appropriately.
Take-home message
Routine antibiotic use potentially impacts antimicrobial resistance, and appropriate use of these drugs is one key to curbing the emergence of resistant pathogens.
Weese JS, Faires MC, Frank LA, et al. Factors associated with methicillin-resistant versus methicillin-susceptible Staphylococcus pseudintermedius infection in dogs. J Am Vet Med Assoc 2012;240(12):1450-1455.
Link to abstract: http://avmajournals.avma.org/doi/abs/10.2460/javma.240.12.1450