title: Human infections due to Staphylococcus pseudintermedius, an emerging zoonosis of canine origin: report of 24 cases.
abstract: BACKGROUND
  Staphylococcus pseudintermedius has been recently identified as a novel species within the genus Staphylococcus, and is commonly associated with infections in dogs. Currently, there are few reports of human infections due to this bacterium.
  
  
  OBJECTIVE
  To use a population-based approach to describe the characteristics of human S. pseudintermedius infections in a large Canadian healthcare region.
  
  
  METHODS
  All adult cases aged ≥18 years identified at a large regional laboratory from April 1, 2013 to April 1, 2015 who had at least one positive culture for S. pseudintermedius were retrospectively reviewed. A combination of phenotypic methods, mass spectrometry (i.e., MALDI-TOF), and cpn60 sequencing were used to identify S. pseudintermedius. Chart review was conducted, and cases were analysed descriptively.
  
  
  RESULTS
  Twenty-seven isolates of S. pseudintermedius from 24 human cases were included for analysis. 58.3% were male with median age of 61 years (IQR 55-70.5). Most patients [22 (92.1%)] had confirmed contact with dogs at time of infection. S. pseudintermedius was isolated in 18 cases (75.0%) of skin and soft tissue infections (SSTI), and 2 invasive cases (8.3%) including a prosthetic joint and bloodstream infection. The other 4 patients were considered to be colonized (skin - 3; lung - 1). Methicillin resistance was identified in 3 cases with 6 total isolates (22.2%); multi-drug resistance was also demonstrated commonly.
  
  
  CONCLUSIONS
  S. pseudintermedius is most commonly associated with SSTIs in humans. Transmission probably occurs from a pet dog. Species-level identification of S. pseudintermedius is important due to the high prevalence of antibiotic resistance, particularly to methicillin.
authors.affiliation: Department of Medicine, University of Calgary, Calgary, AB. Electronic address: ranjani.somayaji@albertahealthservices.ca.
authors.forename: R
authors.initials: R
authors.lastname: Somayaji
authors.affiliation: Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK.
authors.forename: M A R
authors.initials: MA
authors.lastname: Priyantha
authors.affiliation: Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK.
authors.forename: J E
authors.initials: JE
authors.lastname: Rubin
authors.affiliation: Department of Pathology & Laboratory Medicine and Medicine, University of Calgary, Calgary, AB; Calgary Laboratory Services, Calgary, AB.
authors.forename: D
authors.initials: D
authors.lastname: Church
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001431:Bacteriological Techniques; D002170:Canada / Q000453:epidemiology; D004285:Dogs; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057805:Pets; D012189:Retrospective Studies; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013207:Staphylococcal Skin Infections / Q000453:epidemiology / Q000382:microbiology; D013210:Staphylococcus / Q000302:isolation & purification*; D055815:Young Adult; D015047:Zoonoses / Q000382:microbiology* / Q000635:transmission*
keywords: Human infection; Methicillin resistance; Staphylococcus pseudintermedius; Zoonosis