Evaluation of bacteremia in a pediatric intensive care unit: epidemiology, microbiology, sources sites and risk factors

Abstract

Bacteremia is a common cause of morbidity and mortality in children treated in pediatric intensive care unit (PICU). We have investigated the causative agents of bacteremia in our PICU over a one-year period, to determine mortality associated with such infection and identify the dependent predictors for morbidity and mortality. From 1 January till 31 December 2006, 479 patients were admitted in the PICU and 379 blood culture samples were taken. Samples were incubated in the BACTEC 9050 System, and isolates identified by routine microbiological methods. A pair of samples taken for aerobic and anaerobic culture were statistically regarded as one sample. Data collected from the medical records of each patient were recorded onto standardized collections sheets and included demographic information, predisposing conditions, source(s) of infection, important clinical and laboratory parameters at the time of infection, and microbiological data. Based on these data, positive blood cultures were classified as either contaminants or true bacteremias. During a year period, 117 episodes of bacteremia were documented in 72 patients. The most frequent isolates were the coagulase-negative staphylococci 32.2% (39), followed by Candida spp. 30.5% (36). The mean white blood cell count (WBC) on the day of bacteremia was 15.2 x 10(9)/L (range 0.1-48.0 x 10(9)/L), and 3.3% of episodes occurred in neutropenic (WBC count < 1 x 10(9)/L) children. The mean temperature on the day of infection was 38.2 +/- 1.1 degrees C (range, 34-41 degrees C). Some newborns 23% (n = 5) had a significantly lower mean temperature (p < 0.02) and lower mean WBC count (p < 0.05) than older children. Hemodynamic instability was noted in 11% of bacteremic episodes. Among all bacteremias, intravascular catheters were implicated in 22.6%, pneumonia in 20.4%, genitourinary tract in 14.2%, surgical wounds in 11.7% and, gastrointestinal tract in 9.8%. Seven patients died because of sepsis. Early diagnosis, prompt blood culture reports, followed by appropriate antibiotic treatment is essential in reducing mortality in such patients. Short hospital stay and restricted use of invasive devices should be the aims to reduce the risk of bacteremia during the stay in the PICU.