title: Prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) from skin and carriage sites of dogs after treatment of their meticillin-resistant or meticillin-sensitive staphylococcal pyoderma.
abstract: BACKGROUND
  Meticillin-resistant staphylococci are significant pathogens in veterinary dermatology, yet longitudinal studies of the impact of routine antimicrobial therapy on emergence or resolution of resistance are lacking.
  
  
  OBJECTIVE
  To determine the prevalence of meticillin-resistant staphylococci on skin and carriage sites in dogs with bacterial pyoderma and evaluate the prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) colonization after successful treatment of pyoderma.
  
  
  METHODS
  One hundred and seventy-three dogs that presented to a dermatology referral service with pyoderma and 41 healthy control dogs.
  
  
  METHODS
  Skin, nasal and rectal swabs for bacterial culture were collected at the time of referral and after clinical resolution of the pyoderma. Meticillin resistance was confirmed by demonstration of penicillin binding protein 2a antigen.
  
  
  RESULTS
  Initially, skin cultures yielded MRSP in 70 (40.5%) dogs, meticillin-resistant Staphylococcus aureus (MRSA) in three (1.7%) and meticillin-resistant Staphylococcus schleiferi ssp. coagulans (MRSScoag) in five (2.9%). Samples collected from the nose and rectum (carriage sites) yielded MRSP in 59 (34.1%) dogs, MRSA in 11 (6.4%) and MRSScoag in seven (4.0%). One hundred and two dogs were available for follow-up cultures after clinical cure. Of 42 dogs initially diagnosed with MRSP pyoderma, MRSP was isolated at follow-up from skin in 19 (45.2%) and carriage sites in 20 (47.6%). Of 60 dogs that did not have MRSP pyoderma initially, MRSP was isolated post-treatment from the skin in 17 (28.3%), and MRSP from carriage sites increased from 7.8% (initially) to 26.7% (P = 0.0022).
  
  
  CONCLUSIONS
  Colonization by MRSP often persists after resolution of MRSP pyoderma. Acquisition of MRSP during treatment appears to be common.
authors.affiliation: Veterinary Emergency Clinic and Referral Centre, 920 Yonge Street Suite 117, Toronto, Ontario M4W 3C7, Canada. kbeckvet@gmail.com
authors.forename: Karri M
authors.initials: KM
authors.lastname: Beck
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Waisglass
authors.forename: Hani L N
authors.initials: HL
authors.lastname: Dick
authors.forename: J Scott
authors.initials: JS
authors.lastname: Weese
mesh_terms: D000818:Animals; D002353:Carrier State; D004283:Dog Diseases / Q000382:microbiology*; D004285:Dogs; D016106:Methicillin Resistance; D009666:Nose / Q000382:microbiology; D011711:Pyoderma / Q000382:microbiology / Q000662:veterinary*; D012007:Rectum / Q000382:microbiology; D012867:Skin / Q000382:microbiology; D013207:Staphylococcal Skin Infections / Q000382:microbiology / Q000662:veterinary*; D013210:Staphylococcus / Q000187:drug effects* / Q000302:isolation & purification*