Prevalence and Epidemiology of Microbial Pathogens Causing Bloodstream Infections: Results of the OASIS Multicenter Study

Diagn Microbiol Infect Dis. 2011 Apr;69(4):363-9. doi: 10.1016/j.diagmicrobio.2010.10.016.

Abstract

Beginning on April 2007, a prospective multicenter study was performed to investigate prevalence and epidemiology of microbial pathogens causing bloodstream infections (BSIs). Twenty microbiology laboratories participated to the survey over a 1-year period. A total of 11,638 episodes of BSI occurred in 11 202 patients, with 8.5% (n=985) of episodes being polymicrobial. Of 12 781 causative organisms, aerobic Gram-negative bacteria were 47.4% (n=6058), whereas Gram-positives accounted for 43.9% (n=5608). The remaining organisms included fungal species (n=924, 7.2%) and anaerobes (n=191, 1.5%). The most prevalent agents were Escherichia coli (21.7%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (8.2%), Pseudomonas aeruginosa (7.0%), and Enterococcus faecalis (6.3%). Isolates recovered from patients admitted to medical, surgical, and intensive care units accounted for 62.9%, 17.7%, and 19.4% of cases, respectively. BSIs were classified as hospital-acquired in 67.2% of cases. Compared with previous studies, our data show an increasing role of Gram-negative bacteria among both hospital- and community-acquired blood isolates.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Bacteremia / epidemiology
  • Bacteremia / microbiology*
  • Community-Acquired Infections / epidemiology
  • Community-Acquired Infections / microbiology
  • Cross Infection / epidemiology
  • Cross Infection / microbiology
  • Female
  • Gram-Negative Bacteria / classification
  • Gram-Negative Bacteria / isolation & purification*
  • Gram-Positive Bacteria / classification
  • Gram-Positive Bacteria / isolation & purification*
  • Humans
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies