Clinical outcomes of type III Pseudomonas aeruginosa bacteremia

Ali A. El-Solh*, Angela Hattemer, Alan R. Hauser, Ahmad Alhajhusain, Hardik Vora

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

Background: Pseudomonas aeruginosa bacteremia is a serious and life-threatening infection associated with high mortality. Among the multitude of virulence determinants possessed by P. aeruginosa, the type 3 secretion system has been implicated with more acute and invasive infection in respiratory diseases. However, the relationship between the type 3 secretion system and clinical outcomes in P. aeruginosa bacteremia has not been investigated. Objectives: To determine the association between the type 3 secretion system virulence factor in P. aeruginosa bloodstream infection and 30-day mortality. Design: Retrospective analysis of 85 cases of P. aeruginosa bacteremia. Setting: Tertiary care hospital. Interventions: Bacterial isolates were assayed in vitro for secretion of type 3 exotoxins (ExoU, ExoT, and ExoS). Strain relatedness was analyzed using randomly amplified polymorphic DNA polymerase chain reaction genotyping. Antimicrobial susceptibilities were determined by means of the Kirby-Bauer disk-diffusion test. Measurements and Main Results: At least one of the type 3 secretion system proteins was detected in 37 out of the 85 isolates (44%). Septic shock was identified in 43% of bacteremic patients with type 3 secretion system+ isolates compared to 23% of patients with type 3 secretion system-isolates (p = .12). A high frequency of resistance in the type 3 secretion system+ isolates was observed to ciprofloxacin (59%), cefepime (35%), and gentamicin (38%). There was a significant difference in the 30-day cumulative probability of death after bacteremia between secretors and nonsecretors (p = .02). None of the type 3 secretion system+ patients who survived the first 30 days had a P. aeruginosa isolate which exhibited ExoU phenotype. Conclusions: The expression of type 3 secretion system exotoxins in bacteremic isolates of P. aeruginosa confers poor clinical outcomes independent of antibiotic susceptibility profile.

Original languageEnglish (US)
Pages (from-to)1157-1163
Number of pages7
JournalCritical care medicine
Volume40
Issue number4
DOIs
StatePublished - Apr 2012

Keywords

  • Pseudomonas
  • antimicrobial resistance
  • bloodstream infection
  • mortality
  • shock
  • type III secretion system

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

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