title: Healthcare-associated bloodstream infection: A distinct entity? Insights from a large U.S. database.
abstract: OBJECTIVE
  To gain a better understanding of the epidemiology, microbiology, and outcomes of early-onset, culture-positive, community-acquired, healthcare-associated, and hospital-acquired bloodstream infections.
  
  
  METHODS
  We analyzed a large U.S. database (Cardinal Health, MediQual, formerly MedisGroups) to identify patients with bacterial or fungal bloodstream isolates from 2002 to 2003.
  
  
  METHODS
  The data set included administrative and clinical variables (physiologic, laboratory, culture, and other clinical) from 59 hospitals. Bloodstream infections were identified in those hospitals collecting clinical and culture data for at least the first 5 days of admission.
  
  
  METHODS
  Patients with bloodstream infection within 2 days of admission were classified as having community-acquired bloodstream infection. Those with a prior hospitalization within 30 days, transfer from another facility, ongoing chemotherapy, or long-term hemodialysis were classified as having healthcare-associated bloodstream infection. Bloodstream infections that developed after day 2 of admission were classified as hospital-acquired bloodstream infection. A total of 6,697 patients were identified as having bloodstream infection.
  
  
  METHODS
  None.
  
  
  RESULTS
  Healthcare-associated bloodstream infection accounted for more than half (55.3%) of all bloodstream infections. Nearly two thirds (62.3%) of hospitalized patients with bloodstream infection suffered from either hospital-acquired bloodstream infection or healthcare-associated bloodstream infection and had higher morbidity and mortality rates than those with community-acquired bloodstream infection. Of all bloodstream infection pathogens, fungal organisms were associated with the highest crude mortality, longest length of stay in hospital, and greatest total charges. Of all bacterial bloodstream infections, methicillin-resistant Staphylococcus aureus was associated with the highest crude mortality rate (22.5%), the longest mean length of stay (11.1 +/- 10.7 days), and the highest median total charges ($36,109). After we controlled for confounding factors, methicillin-resistant S. aureus was associated with the highest independent mortality risk (odds ratio 2.70; confidence interval 2.03-3.58). S. aureus was the most commonly encountered pathogen in all types of early-onset bacteremia.
  
  
  CONCLUSIONS
  Healthcare-associated bloodstream infection constitutes a distinct entity of bloodstream infection with its unique epidemiology, microbiology, and outcomes. Methicillin-resistant Staphylococcus aureus carries the highest relative mortality risk among all pathogens.
authors.affiliation: Washington Hospital Center, Washington, DC, USA.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
authors.forename: Ying P
authors.initials: YP
authors.lastname: Tabak
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Killian
authors.forename: Vikas
authors.initials: V
authors.lastname: Gupta
authors.forename: Larry Z
authors.initials: LZ
authors.lastname: Liu
authors.forename: Marin H
authors.initials: MH
authors.lastname: Kollef
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000145:classification* / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy; D005260:Female; D016469:Fungemia / Q000145:classification* / Q000453:epidemiology / Q000382:microbiology / Q000628:therapy; D017722:Hospital Charges; D006801:Humans; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D009626:Terminology as Topic; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology