Clinical characteristics and risk factors for attributable mortality in Enterobacter cloacae bacteremia

Yi-Chun Lin¹, Te-Li Chen², Huang-Ling Ju², Huan-Shen Chen³, Fu-Der Wang², Kwok-Woon Yu⁴, Chen Yi Liu^2
1Department of Medicine, Taichung Hospital, Department of Health, The Executive Yuan, Taichung; ²Section of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital and National Yang-Ming University, Taipei; ³Department of Medicine, Li Shin Hospital, Taoyuan; and ⁴Department Pathology and Laboratory Medicine, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan

Received: June 3, 2005 Revised: July 25, 2005 Accepted: August 18, 2005

Corresponding author: Fu-Der Wang, Section of Infectious Diseases,Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan. E-mail:

Background and Purpose: Enterobacter spp. have emerged as an important cause of nosocomial bacteremia. The purpose of this study was to delineate the clinical, laboratory and microbiologic features that may influence prognosis of Enterobacter cloacae and enable a stratification of those patients at high risk of mortality.
Methods: This retrospective study reviewed 108 episodes of E. cloacae bacteremia occurring over a 2-year period (November 2001 to October 2003) at Taipei Veterans General Hospital. Univariate analysis were performed to demonstrate the relation of possible risk factors to death attributable to E. cloacae bacteremia.
Results: Ninety-three episodes (86.1%) were hospital-acquired. The most common portal of entry was the genitourinary tract (17.9%) followed by the gastrointestinal tract (15.1%). Underlying diseases associated with E. cloacae bacteremia were neoplastic diseases (42 episodes, 38.9%), diabetes mellitus (20 episodes, 18.5%) and chronic renal failure (18 episodes, 16.7%). The overall mortality rate was 42.6%, and E. cloacae bacteremia-attributable mortality occurred in 22 patients (20.9%). Factors significantly correlated with death attributable to bacteremia were older age, a higher medium number of underlying diseases, hemoglobin <10 g/dL, serum C-reactive protein >10 mg/dL, hypoalbuminemia, disseminated intravascular coagulation, septic shock, respiratory failure, renal failure (creatinine >2 mg/dL) and delayed clinical response after initiation of antibiotic therapy.
Conclusions: Antibiotic-resistant isolates and appropriate empirical antibiotic use were not independent predictors of mortality in this study. The condition of patients at onset of symptoms and presence of underlying diseases appear to be important predictors mortality from E. cloacae bacteremia.

Key words: Bacteremia, comorbidity, Enterobacter cloacae, prognosis, risk factors

J Microbiol Immunol Infect 2006;39:67-72.