title: Mixed bloodstream infections involving bacteria and Candida spp.
abstract: OBJECTIVE
  Polymicrobial bloodstream infection (BSI) is an imprecisely defined entity purportedly associated with a worse outcome than monomicrobial BSI. This study examines trends in BSI episodes caused by bacteria and Candida spp. (mixed-BSI) in a large teaching hospital.
  
  
  METHODS
  All episodes of BSI from January 2000 to December 2010 were reviewed. Three groups (n = 54 each) of patients were compared: all adults with mixed-BSI from January 2006 to December 2010 (cases) and randomly selected patients with polybacterial BSI (polyB-BSI) (Control 1) or Candida spp. BSI (Candida-BSI) (Control 2) in this same period.
  
  
  RESULTS
  A total of 139 episodes of mixed-BSI were recorded (0.7% of all BSI, 6.9% of all poly-BSI and 18.0% of all Candida-BSI episodes). The incidence of mixed-BSI was 0.21 cases/1000 admissions, increasing from 0.08 (2000) to 0.34 (2010) cases/1000 admissions (P = 0.007). Mixed-BSI represented 11.8% and 22.9% of all episodes of candidaemia in 2000 and 2010, respectively (P = 0.011). Compared with polyB-BSI, mixed-BSI patients showed fewer malignancies, more frequent nosocomial or intravenous catheter BSI source and less frequent intra-abdominal origin, were more frequently admitted to an intensive care unit (ICU), received more antimicrobials and showed a longer hospital stay and higher mortality. Compared with Candida-BSI, mixed-BSI patients showed more severe underlying diseases, were more frequently admitted to an ICU or oncology-haematology unit, showed a higher APACHE II score, more often progressed to septic shock or multiorgan failure and received more antimicrobials. Mortality was similar.
  
  
  CONCLUSIONS
  Mixed-BSI is a rare, distinct infection with a worse prognosis than polyB-BSI. We were unable to detect differences in the prognosis of mixed-BSI when compared with Candida-BSI.
authors.affiliation: Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Bouza
authors.forename: Almudena
authors.initials: A
authors.lastname: Burillo
authors.forename: Patricia
authors.initials: P
authors.lastname: Muñoz
authors.forename: Jesús
authors.initials: J
authors.lastname: Guinea
authors.forename: Mercedes
authors.initials: M
authors.lastname: Marín
authors.forename: Marta
authors.initials: M
authors.lastname: Rodríguez-Créixems
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000150:complications* / Q000453:epidemiology*; D058387:Candidemia / Q000150:complications* / Q000453:epidemiology*; D015331:Cohort Studies; D060085:Coinfection / Q000453:epidemiology*; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: bacteraemia; candidaemia; coinfection; polymicrobial bacteraemia; polymicrobial candidaemia