title: Opioid and amphetamine dependence is associated with methicillin-resistant Staphylococcus aureus (MRSA): An epidemiological register study with 73,201 Swedish in- and outpatients 1997-2013.
abstract: BACKGROUND
  While methicillin-resistant Staphylococcus aureus (MRSA) is increasing in prevalence globally, Sweden is still a low-prevalence country enabling studies on the natural MRSA spread in subpopulations unaffected by a surrounding highly infected population. Substance dependence and injection drug use have been risk factors for MRSA carriage and infection in other countries. In this retrospective, longitudinal register study, we investigated MRSA epidemiology 1997-2013 in opioid and amphetamine-dependent individuals, in comparison with alcohol-dependent subjects.
  
  
  METHODS
  Data from the national Swedish in- and outpatients registers included 73,201 individuals from 1997, 1999, 2004, 2009 and 2013. We analyzed substance use disorder and demographic predictors for MRSA using generalized estimating equations.
  
  
  RESULTS
  The main finding was that both opioid (adjusted odds ratio [AOR] = 2.82; 95% confidence interval [CI] = 2.16, 3.67) and amphetamine dependence (AOR = 2.71; 95% CI = 1.70, 4.16) were significantly associated with MRSA diagnosis compared with alcohol dependence, when adjusting for age, sex and year.
  
  
  CONCLUSIONS
  These findings are of value to understand the dynamics of MRSA epidemiology among substance dependent persons with presumably low socioeconomic status and potential injection drug use, and implicate repeated surveillance of MRSA among these patients.
authors.affiliation: a Division of Psychiatry, Department of Clinical Sciences Lund , Lund University , Lund , Sweden.|b Malmo Addiction Centre , Malmo , Sweden.
authors.forename: Disa
authors.initials: D
authors.lastname: Dahlman
authors.affiliation: a Division of Psychiatry, Department of Clinical Sciences Lund , Lund University , Lund , Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Berge
authors.affiliation: c Infectious Disease Research Unit, Department of Translational Medicine , Lund University , Lund , Sweden.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Nilsson
authors.affiliation: d Behavioral and Urban Health Program , RTI International , San Francisco , CA , USA.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Kral
authors.affiliation: c Infectious Disease Research Unit, Department of Translational Medicine , Lund University , Lund , Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Bjorkman
authors.affiliation: a Division of Psychiatry, Department of Clinical Sciences Lund , Lund University , Lund , Sweden.
authors.forename: Anders C
authors.initials: AC
authors.lastname: Hakansson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000437:Alcoholism / Q000150:complications; D019969:Amphetamine-Related Disorders / Q000150:complications*; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007297:Inpatients; D008137:Longitudinal Studies; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008875:Middle Aged; D009293:Opioid-Related Disorders / Q000150:complications*; D010045:Outpatients; D015995:Prevalence; D012042:Registries; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Methicillin-resistance; Staphylococcus aureus; epidemiology; people who inject drugs; substance dependence