title: A matched prospective cohort study on Staphylococcus aureus and Escherichia coli bloodstream infections: extended perspectives beyond resistance.
abstract: BACKGROUND
  Bacteremias caused by Staphylococcus aureus and Escherichia coli are among the most common bloodstream infections (BSIs) in adults. The aim of the study was to investigate risk factors for infection and clinical outcomes of bacteremias caused by S aureus or E coli.
  
  
  METHODS
  We conducted a 1-year matched prospective cohort study including 150 patients with BSI caused by susceptible or resistant S aureus or E coli and 300 controls without BSI caused by these organisms.
  
  
  RESULTS
  Of the 150 episodes of bacteremia, 37% were caused by S aureus (including 5 cases of methicillin-resistant S aureus [MRSA]) and 63% were caused by E coli (including 9 cases of extended-spectrum beta lactamase [ESBL]-producing E coli). We identified 4 independent risk factors for acquisition of S aureus bacteremia (emergency, peripheral or central vascular catheter, renal disease) and 6 risk factors for E coli bacteremia (emergency, peripheral or central vascular catheter, malignancy, cytoreductive or immunosuppressive therapy). Both types of bacteremia were associated with an increased length of hospital stay compared with controls. We observed a 5-fold increase in the 30-day mortality rate for bacteremias due to S aureus, and a 2-fold increase in BSI caused by E coli. The in-hospital mortality rate was increased by 6-fold for S aureus and by 3-fold for E coli.
  
  
  CONCLUSIONS
  Longer hospitalization periods and increased mortality of bacteremias caused by S aureus or E coli, irrespective of susceptibility, implicate controlling for risk factors at an early stage.
authors.affiliation: Division of Hospital Hygiene, Clinical Institute for Hygiene and Medical Microbiology, Vienna General Hospital, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, Austria.
authors.forename: Jutta
authors.initials: J
authors.lastname: Berger
authors.forename: Magda
authors.initials: M
authors.lastname: Diab-Elschahawi
authors.forename: Alexander
authors.initials: A
authors.lastname: Blacky
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Pernicka
authors.forename: Verena
authors.initials: V
authors.lastname: Spertini
authors.forename: Ojan
authors.initials: O
authors.lastname: Assadian
authors.forename: Walter
authors.initials: W
authors.lastname: Koller
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Aichberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D016022:Case-Control Studies; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents