title: Transregional spread of a single clone of methicillin-resistant Staphylococcus aureus between groups of drug users in Switzerland.
abstract: BACKGROUND
  An epidemic spread of methicillin-resistant Staphylococcus aureus (MRSA) among intravenous drug users (IDUs) has been observed in Zurich. In the present study we investigated the situation in the Grisons, Switzerland.
  
  
  METHODS
  We screened IDUs and their caregivers in medical and socio-therapeutical institutions in the Grisons for MRSA. Nose swabs were used for bacterial culture and pulsed-field gel electrophoresis for MRSA genotyping.
  
  
  RESULTS
  A total of 191 nose swabs from 111 IDUs and 80 caregivers was analyzed. None of the caregivers was MRSA positive. Six IDUs were asymptomatic MRSA carriers (5.4%). They participated in the official heroin program (MRSA prevalence in this group 16%). The MRSA genotype was identical with the single clone found in IDUs in Zurich, strongly suggesting an epidemic spread. Decolonization was successful in two persons only. Persistence of MRSA in IDUs must therefore be assumed.
  
  
  CONCLUSIONS
  We conclude that a single clone of MRSA, found in IDUs in Zurich, has spread to a distant region of Switzerland. A rigorous infection control program in all institutions with IDUs is necessary to prevent a further spread of MRSA.
authors.affiliation: Dept. of Internal Medicine and Laboratory of Microbiology, Kantonsspital, 7000 Chur, Switzerland. felix.fleisch@scag.gr.ch
authors.forename: F
authors.initials: F
authors.lastname: Fleisch
authors.forename: E C
authors.initials: EC
authors.lastname: Oechslin
authors.forename: A R
authors.initials: AR
authors.lastname: Gujer
authors.forename: E
authors.initials: E
authors.lastname: Ritzler
authors.forename: A
authors.initials: A
authors.lastname: Imhof
authors.forename: C
authors.initials: C
authors.lastname: Ruef
authors.forename: W H
authors.initials: WH
authors.lastname: Reinhart
mesh_terms: D000328:Adult; D017028:Caregivers; D002353:Carrier State; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D015995:Prevalence; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000472:pathogenicity*; D015819:Substance Abuse, Intravenous; D013557:Switzerland / Q000453:epidemiology