Enterobacter bacteremia: clinical features and emergence of antibiotic resistance during therapy

Ann Intern Med. 1991 Oct 15;115(8):585-90. doi: 10.7326/0003-4819-115-8-585.


Objectives: To study the effect of previously administered antibiotics on the antibiotic susceptibility profile of Enterobacter, the factors affecting mortality, and the emergence of antibiotic resistance during therapy for Enterobacter bacteremia.

Design: Prospective, observational study of consecutive patients with Enterobacter bacteremia.

Setting: Three university tertiary care centers, one major university-affiliated hospital, and two university-affiliated Veterans Affairs medical centers.

Patients: A total of 129 adult patients were studied.

Measurements: The two main end points were emergence of resistance during antibiotic therapy and death.

Main results: Previous administration of third-generation cephalosporins was more likely to be associated with multiresistant Enterobacter isolates in an initial, positive blood culture (22 of 32, 69%) than was administration of antibiotics that did not include a third-generation cephalosporin (14 of 71, 20%; P less than 0.001). Isolation of multiresistant Enterobacter sp. in the initial blood culture was associated with a higher mortality rate (12 of 37, 32%) than was isolation of a more sensitive Enterobacter sp. (14 of 92, 15%; P = 0.03). Emergence of resistance to third-generation cephalosporin therapy (6 of 31, 19%) occurred more often than did emergence of resistance to aminoglycoside (1 of 89, 0.01%; P = 0.001) or other beta-lactam (0 of 50; P = 0.002) therapy.

Conclusions: More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp., which in turn may result in a lower mortality for Enterobacter bacteremia. When Enterobacter organisms are isolated from blood, it may be prudent to avoid third-generation cephalosporin therapy regardless of in-vitro susceptibility.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Aminoglycosides
  • Analysis of Variance
  • Anti-Bacterial Agents / pharmacology
  • Cephalosporins / pharmacology
  • Drug Resistance, Microbial
  • Drug Therapy, Combination / therapeutic use
  • Enterobacter / drug effects*
  • Enterobacteriaceae Infections / drug therapy*
  • Enterobacteriaceae Infections / mortality
  • Female
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Prospective Studies
  • Sepsis / drug therapy*
  • Sepsis / microbiology
  • Sepsis / mortality


  • Aminoglycosides
  • Anti-Bacterial Agents
  • Cephalosporins