Epidemiology of bloodstream infection

Bloodstream infections tare associated with high mortality. The incidence o f bloodstream infections is increasing worldwide, with a shift towards mult iresistant pathogens such as me thicillin-resistant Staphylococcus aureus, enterococci and Candida spp. This study analysed retrospectively 1814 episo des of bacteraemia from 1993 to 1997 at a single tertiary care centre. True bloodstream infections was defined as clinical sepsis and positive blood c ulture without evidence for contamination of skin bacteria. Of the 1814 epi sodes, 380 (20.9%) were contaminated, resulting in 1434 true episodes of bl oodstream infection. 42% were nosocomial bloodstream infections and one fou rth were primary bloodstream infections. The incidence of bloodstream infec tions increased from 13.0/10000 patient-days (1993) to 15.8/10 000 patient- days (1997). Mortality increased from 15.4% (1993) to 21% (1997) (p = 0.059 ). The five most frequently isolated microorganisms were Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, coagulase-negative staphyl ococci and streptococci. The distribution of bacteria did not change over t ime from 1993 to 1998. Multiresistant bacteria such as methicillin-resistan t Staphylococcus aureus, enterococci, Pseudomonas spp. and yeasts were isol ated in less than 5% of episodes. In addition, there is a trend towards dec reasing resistance, in contrast to most other institutions in Southern Euro pe and the US. Further analyses and studies are necessary to answer questio ns raised by this retrospective study.