[Nosocomial bacteremia caused by Enterobacter spp.: epidemiology and prognostic factors]

Abstract

Background: The aim of this study was to establish the clinical and epidemiologic features of nosocomial bacteremia by Enterobacter spp. and to analyse its prognostic factors.

Methods: A prospective study of the episodes of nosocomial bacteremia by Enterobacter spp. with clinical significance, detected in a third level university hospital from January 1984 to December 1990 was performed.

Results: During the study period, 226 episodes of bacteremia by Enterobacter spp., of which 184 (81%) were of nosocomial origin (8.1% of all the nosocomial bacteremias), while 14% were polymicrobial. An increasing trend was observed in the number of episodes (1984 vs 1990) from 0.9 vs 1.8 episodes per 1,000 admissions, respectively. The mean age was 57 years and the male/female relation was 2.4/1. The most frequent focus of origin was infection of the vascular catheter (43%), followed by intraabdominal catheter (21%), urinary tract (14%), and other foci (17%). Fifty-four percent of the patients had received antibiotics prior to the episode of bacteremia. Most of the cases were detected in the Intensive Care Units (ICU) (41%) and in the gastrointestinal surgery area (24%). Global mortality was 23%. Logistic regression analysis selected an entry site other than infection of the vascular catheter (odds ratio 6.1; CI [95%)] 2.0-18.4), shock (odds ratio, 6; CI [95%], 1.6-21.9) and immunosuppressive treatment (odds ratio, 5; CI [95%], 1.5-16.2) as independent variables of bad prognosis.

Conclusions: Enterobacter spp. is an important nosocomial pathogen taking fourth place in the ranking of nosocomial bacteremia by gram negative bacilli. It predominantly affects a population of patients admitted in the ICU and surgery. The intravascular catheter is a frequent entry site for nosocomial bacteremia by Enterobacter spp.