title: Fluoroquinolone use is a risk factor for methicillin-resistant Staphylococcus aureus acquisition in long-term care facilities: a nested case-case-control study.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is a well-established risk factor for subsequent infection and a key event in interindividual transmission. Some studies have showed an association between fluoroquinolones and MRSA colonization or infection. The present study was performed to identify specific risk factors for MRSA acquisition in long-term care facilities (LTCFs).
  
  
  METHODS
  A prospective cohort of patients naive for S. aureus colonization was established and followed (January 2008 through October 2010) in 4 French LTCFs. Nasal colonization status and potential risk factors were assessed weekly for 13 weeks after inclusion. Variables associated with S. aureus acquisition were identified in a nested-matched case-case-control study using conditional logistic regression models. Cases were patients who acquired MRSA (or methicillin-sensitive S. aureus [MSSA]). Patients whose nasal swab samples were always negative served as controls. Matching criteria were center, date of first nasal swab sample, and exposure time.
  
  
  RESULTS
  Among 451 included patients, 76 MRSA cases were matched to 207 controls and 112 MSSA cases to 208 controls. Multivariable analysis retained fluoroquinolones (odds ratio, 2.17; 95% confidence interval, 1.01-4.67), male sex (2.09; 1.10-3.98), and more intensive care at admission (3.24; 1.74-6.04) as significantly associated with MRSA acquisition, and body-washing assistance (2.85; 1.27-6.42) and use of a urination device (1.79; 1.01-3.18) as significantly associated with MSSA acquisition.
  
  
  CONCLUSIONS
  Our results suggest that fluoroquinolones are a risk factor for MRSA acquisition. Control measures to limit MRSA spread in LTCFs should also be based on optimization of fluoroquinolone use.
authors.affiliation: Unité de Pharmaco-Épidémiologie et Maladies Infectieuses, Institut Pasteur, Paris U657, Institut National de la Santé et de la Recherche Médicale, Paris EA 4499, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Couderc
authors.affiliation: Unité de Pharmaco-Épidémiologie et Maladies Infectieuses, Institut Pasteur, Paris U657, Institut National de la Santé et de la Recherche Médicale, Paris EA 4499, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Sarah
authors.initials: S
authors.lastname: Jolivet
authors.affiliation: Unité de Pharmaco-Épidémiologie et Maladies Infectieuses, Institut Pasteur, Paris U657, Institut National de la Santé et de la Recherche Médicale, Paris EA 4499, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Anne C M
authors.initials: AC
authors.lastname: Thiébaut
authors.affiliation: Unité de Pharmaco-Épidémiologie et Maladies Infectieuses, Institut Pasteur, Paris U657, Institut National de la Santé et de la Recherche Médicale, Paris EA 4499, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Caroline
authors.initials: C
authors.lastname: Ligier
authors.affiliation: Service de Microbiologie, Hôpital Raymond Poincaré, Garches.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Remy
authors.affiliation: Service de Microbiologie, Hôpital Raymond Poincaré, Garches.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Alvarez
authors.affiliation: Service de Microbiologie, Hôpital Raymond Poincaré, Garches.
authors.forename: Christine
authors.initials: C
authors.lastname: Lawrence
authors.affiliation: Laboratoire Modélisation Épidémiologie et Surveillance des Risques Sanitaires, Conservatoire National des Arts et Métiers, Paris.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Salomon
authors.affiliation: Service de Microbiologie, Hôpital Raymond Poincaré, Garches EA 3647, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Herrmann
authors.affiliation: Unité de Pharmaco-Épidémiologie et Maladies Infectieuses, Institut Pasteur, Paris U657, Institut National de la Santé et de la Recherche Médicale, Paris EA 4499, Université de Versailles-Saint-Quentin-en-Yvelines, Montigny le Bretonneux.
authors.forename: Didier
authors.initials: D
authors.lastname: Guillemot
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D016022:Case-Control Studies; D015331:Cohort Studies; D004363:Drug Utilization; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use*; D005602:France; D006801:Humans; D015994:Incidence; D008134:Long-Term Care / Q000379:methods*; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008875:Middle Aged; D009297:Nasal Mucosa / Q000382:microbiology; D011446:Prospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones
keywords: acquisition; case-case-control study; fluoroquinolone; long-term care facility; methicillin-resistant Staphylococcus aureus