Bacteremia at a Danish University Hospital during a Twenty-five-year Period (1968-1892)

Abstract

In the 25-year period 1968-92, 3,317 out of 477,420 patients admitted to Frederiksberg Hospital experienced 3,491 episodes of bacteremia. Enterobacteriaceae dominated as causative agents (57%), following by Gram-positive cocci (31%) and anaerobes (7%). Polymicrobial bacteremia was found in 8% of the episodes. The incidence of Enterobacteriaceae bacteremia culminated in the middle (1978-82) of the period (4.7/1,000 admissions) and decreased during the last decade. Gram-positive bacteremia increased throughout the period (from 1.8 to 2.9; p < 0.001), due mainly to increasing incidences of bacteremia caused by non-hemolytic streptococci, Streptococcus pneumoniae and coagulase-negative staphylococci. Bacteroides fragilis accounted for a rising incidence of anaerobic bacteremia (from 0.3 to 0.7; p < 0.05). Clinical data were available for the 2,599 bacteremic episodes in the 20-year period 1968-87. 59% of these were hospital acquired. Of those, 38% were associated with indwelling catheters, mainly bladder catheters (28%) and i.v. lines (7%). The urinary tract dominated as source of bacteremia (46%), followed by the respiratory (11%) and the gastrointestinal tract (9%). Half of the patients had predisposing underlying diseases, most frequently malignancies (20%) and diabetes mellitus (7%). The mortality rate related to bacteremia decreased from 25% to 11% (p < 0.001). More than half (55%) of the fatal cases related to bacteremia occurred within the first 2 days after the first positive blood culture was obtained. Logistic regression analysis defined 7 variables that independently influenced the outcome related to bacteremia: age, source, culture verification of source, shock, body temperature, leukocyte count and empiric antibiotic treatment. A local knowledge of the most common causative microorganisms, the most common sources and the outcome of bacteremia, are of the utmost importance in the selection of the initial empirical antibiotic regimens.