Changing epidemiology of bloodstream infection in a 25-years hematopoietic stem cell transplant program: current challenges and pitfalls on empiric antibiotic treatment impacting outcomes.

We aimed to describe epidemiology changes in bloodstream infections (BSI) episodes in hematopoietic stem cell transplant (HSCT) recipients throughout a 25-year period (1993-2017), comparing five-year time spans, and we evaluate their impact on inappropriate empirical antibiotic treatment (IEAT) and mortality. During the study period, 1164 BSI episodes were documented in patients undergoing HSCT (71.6% allogenic and 29% autologous). A significant decrease in gram-positive cocci (GPC) and increase in gram-negative bacilli (GNB) were observed (p < 0.001). Among GP, coagulase-negative staphylococci (CoNS) significantly decreased whereas rising E. faecium BSI was documented. Among GNB, E. coli, Pseudomonas aeruginosa and K. pneumoniae rates increased. Multidrug-resistant (MDR) GNB, especially ESBL-E. coli and MDR-P. aeruginosa, emerged in 2008 and has gradually increased. IEAT against MDR-P. aeruginosa, but not in other MDR-GNB, augmented throughout the study period. Overall, 30-day and related mortality rates were 12.7% and 7.7% respectively, both increasing over time (p < 0.001 and p = 0.025). In GNB, 30-day and related mortality were 18.5% and 12.8%, respectively, increasing over time (p < 0.001 and p = 0.004). To conclude, important BSI epidemiological changes were described in a 25-year period. Concerning increase in IEAT for P. aeruginosa infections and rising 30-day mortality rate were documented.