title: Large outbreak caused by methicillin resistant Staphylococcus pseudintermedius ST71 in a Finnish Veterinary Teaching Hospital--from outbreak control to outbreak prevention.
abstract: BACKGROUND
  The purpose of this study was to describe a nosocomial outbreak caused by methicillin resistant Staphylococcus pseudintermedius (MRSP) ST71 SCCmec II-III in dogs and cats at the Veterinary Teaching Hospital of the University of Helsinki in November 2010 - January 2012, and to determine the risk factors for acquiring MRSP. In addition, measures to control the outbreak and current policy for MRSP prevention are presented.
  
  
  METHODS
  Data of patients were collected from the hospital patient record software. MRSP surveillance data were acquired from the laboratory information system. Risk factors for MRSP acquisition were analyzed from 55 cases and 213 controls using multivariable logistic regression in a case-control study design. Forty-seven MRSP isolates were analyzed by pulsed field gel electrophoresis and three were further analyzed with multi-locus sequence and SCCmec typing.
  
  
  RESULTS
  Sixty-three MRSP cases were identified, including 27 infections. MRSPs from the cases shared a specific multi-drug resistant antibiogram and PFGE-pattern indicated clonal spread. Four risk factors were identified; skin lesion (OR = 6.2; CI95% 2.3-17.0, P = 0.0003), antimicrobial treatment (OR = 3.8, CI95% 1.0-13.9, P = 0.0442), cumulative number of days in the intensive care unit (OR = 1.3, CI95% 1.1-1.6, P = 0.0007) or in the surgery ward (OR = 1.1, CI95% 1.0-1.3, P = 0.0401). Tracing and screening of contact patients, enhanced hand hygiene, cohorting and barrier nursing, as well as cleaning and disinfection were used to control the outbreak. To avoid future outbreaks and spread of MRSP a search-and-isolate policy was implemented. Currently nearly all new MRSP findings are detected in screening targeted to risk patients on admission.
  
  
  CONCLUSIONS
  Multidrug resistant MRSP is capable of causing a large outbreak difficult to control. Skin lesions, antimicrobial treatment and prolonged hospital stay increase the probability of acquiring MRSP. Rigorous control measures were needed to control the outbreak. We recommend the implementation of a search-and-isolate policy to reduce the burden of MRSP.
authors.affiliation: Central Laboratory, Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Grönthal
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Arshnee
authors.initials: A
authors.lastname: Moodley
authors.affiliation: Food and Feed Microbiology Research Unit, Finnish Food Safety Authority Evira, Helsinki, Finland.
authors.forename: Suvi
authors.initials: S
authors.lastname: Nykäsenoja
authors.affiliation: 4Pharma Ltd., Espoo, Finland.
authors.forename: Jouni
authors.initials: J
authors.lastname: Junnila
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Luca
authors.initials: L
authors.lastname: Guardabassi
authors.affiliation: Veterinary Teaching Hospital, University of Helsinki, Helsinki, Finland.
authors.forename: Katariina
authors.initials: K
authors.lastname: Thomson
authors.affiliation: Central Laboratory, Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Merja
authors.initials: M
authors.lastname: Rantala
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000453:epidemiology*; D002415:Cats; D003428:Cross Infection / Q000453:epidemiology / Q000662:veterinary*; D004196:Disease Outbreaks / Q000517:prevention & control*; D004283:Dog Diseases / Q000453:epidemiology*; D004285:Dogs; D005387:Finland; D006762:Hospitals, Animal; D016106:Methicillin Resistance; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000662:veterinary*; D013210:Staphylococcus