title: Emergence of linezolid-resistant coagulase-negative staphylococci in an intensive care unit.
abstract: BACKGROUND
  The aim of this study was to report the emergence of linezolid-resistant coagulase-negative staphylococci (CoNS) in an intensive care unit.
  
  
  METHODS
  An observational study was conducted in critically ill patients with colonization or infection by linezolid-resistant CoNS between January 2010 and December 2014. We analyzed the epidemiological and clinical features, and the mechanism of resistance to linezolid. We also evaluated the association between the incidence of linezolid-resistant CoNS strains and the consumption of linezolid in the study period.
  
  
  RESULTS
  During the study period 49 patients had a linezolid-resistant CoNS strain isolated from clinical samples (blood in 42 cases, urine in 6, peritoneal fluid in 1). Molecular study showed a combination of mechanisms of resistance. Most patients were critically ill (APACHE II score = 21.9 ± 8.3) and nearly all had undergone surgery and invasive procedures, and had prior exposure to antibiotics. Linezolid-resistant CoNS were considered to be contaminants in 42 patients and associated with infection in 7 patients, comprising bacteremia and septic shock in most of them. They were successfully treated with glycopeptides or daptomycin. A modest significant correlation was observed between the decrease in linezolid consumption and the lower incidence of resistant isolates.
  
  
  CONCLUSIONS
  Linezolid-resistant CoNS had emerged in critically ill patients with severe underlying diseases and prior antibiotic exposure. Most isolates represented colonization; however, linezolid-resistant CoNS can produce serious infections in critically ill patients. Glycopeptides and daptomycin seem to provide useful alternatives for therapy of these infections. A relationship was found between linezolid consumption and the incidence of linezolid-resistant CoNS strains.
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Bárbara
authors.initials: B
authors.lastname: Balandin
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Beatriz
authors.initials: B
authors.lastname: Lobo
authors.affiliation: b Department of Microbiology , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Beatriz
authors.initials: B
authors.lastname: Orden
authors.affiliation: c Laboratory of Nosocomial Infections , Centro Nacional de Microbiología, Instituto de Salud Carlos III , Madrid ;
authors.forename: Federico
authors.initials: F
authors.lastname: Román
authors.affiliation: d Department of Hospitalary Pharmacy , Hospital Universitario Puerta de Hierro Majadahonda , Madrid , Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: García
authors.affiliation: b Department of Microbiology , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Rocío
authors.initials: R
authors.lastname: Martínez
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Miguel
authors.initials: M
authors.lastname: Valdivia
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Alfonso
authors.initials: A
authors.lastname: Ortega
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Fernández
authors.affiliation: a Intensive Care Unit , Hospital Universitario Puerta de Hierro Majadahonda , Madrid ;
authors.forename: Pedro
authors.initials: P
authors.lastname: Galdos
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D000069349:Linezolid / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013210:Staphylococcus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D000069349:Linezolid
keywords: Linezolid-resistant; coagulase-negative staphylococci; defined daily dose; intensive care unit