Fluoroquinolones and risk for methicillin-resistant Staphylococcus aureus, Canada

Emerg Infect Dis. 2006 Sep;12(9):1398-405. doi: 10.3201/eid1209.060397.


Receipt of fluoroquinolones was the predominant risk factor for Clostridium difficile-associated disease (CDAD) during an epidemic in Quebec, Canada. To determine the role of antimicrobial drugs in facilitating healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection and to compare this role with their effects on methicillin-susceptible S. aureus infection and CDAD, we conducted a retrospective cohort study of patients in a Quebec hospital. For 7371 episodes of care, data were collected on risk factors, including receipt of antimicrobial drugs. Crude and adjusted hazard ratios (AHR) were calculated by Cox regression. Of 150 episodes of MRSA colonization and 23 of MRSA infection, fluoroquinolones were the only antimicrobials that increased risk for colonization (AHR 2.57, 95% confidence interval [CI] 1.84-3.60) and infection (AHR 2.49, 95% CI 1.02-6.07). Effect of antimicrobial drugs on MRSA colonization and infection was similar to effect on CDAD and should be considered when selecting antimicrobial drugs to treat common infections.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Infective Agents / pharmacology
  • Anti-Infective Agents / therapeutic use*
  • Clostridioides difficile / drug effects
  • Enterocolitis, Pseudomembranous / epidemiology
  • Enterocolitis, Pseudomembranous / microbiology
  • Female
  • Fluoroquinolones / pharmacology
  • Fluoroquinolones / therapeutic use*
  • Humans
  • Male
  • Methicillin / pharmacology
  • Methicillin Resistance*
  • Microbial Sensitivity Tests
  • Middle Aged
  • Quebec
  • Risk Factors
  • Staphylococcal Infections / epidemiology*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / isolation & purification


  • Anti-Infective Agents
  • Fluoroquinolones
  • Methicillin