- We studied the epidemiology, microbiology, clinical aspects and outcome of bloodstream infections (BSI) in a tertiary paediatric intensive care unit. All BSI episodes were prospectively identified and analysed. The paediatric intensive care unit moved in 2006 from an open-plan unit to a new (all single room) unit. Three hundred and fifty-three BSI episodes occurred in 299 of 4162 patients. Overall, BSI incidence was 85 per 1000 hospitalised children. Fewer BSI episodes occurred during the last two years of the study (2007 to 2008), compared with 2000 to 2006 (70 of 1061 admissions, 6.5% versus 283 of 3101 admissions, 9.1%, respectively, P=0.01). There were 127 of 340 (37.4%) community-acquired and 213 of 340 (62.6%) nosocomial BSI episodes (31 of 1000 and 51 of 1000, respectively). Nosocomial BSI episodes decreased during 2007 to 2008 versus 2000 to 2006 (37.7% versus 55.8%, P=0.03). In 448 instances, pathogens were isolated, 231 (52%) Gram-positive and 188 (42%) Gram-negative. Coagulase-negative Staphylococci, S. pneumoniae and S. aureus (41.1%, 19.9% and 11.7%, respectively) were the most common Gram-positive and Enterobacteriaceae spp. the most frequent Gram-negative organisms (45.2%, of them Klebsiella spp. and E. coli 40% and 29.4%, respectively). A significant decrease was recorded during 2007 to 2008 in Enterobacteriaceae resistance to piperacillin, gentamicin and ciprofloxacin. Thirty of 299 (10%, 9 with S. pneumoniae-BSI) patients died. A significant decrease in BSI and nosocomial incidence and Enterobacteriaceae spp. antibiotic resistance was recorded following the conversion of the paediatric intensive care unit from an open ward to an all isolated rooms environment.