Risk Factors for Mortality in Hematopoietic Stem Cell Transplantation Recipients with Bloodstream Infection: Points To Be Addressed by Future Guidelines

In recent years, important epidemiologic changes have been described in hematopoietic stem cell transplantation (HSCT) recipients with bloodstream infection (BSI), with increases in gram-negative bacilli and multidrug resistant (MDR) gram-negative bacilli. These changes have been linked to a worrisome increase in mortality. We aimed to define the risk factors for mortality of HSCT patients experiencing BSI. All episodes of BSI in patients with HSCT between 2008 and 2017 were prospectively collected. Multivariate analyses were performed. A total of 402 BSI episodes were documented in 293 patients who had undergone HSCT (75.4% allogenic, 32.3% autologous, 19.3% second HSCT). The median time from HSCT to BSI was 62 days (interquartile range, 9 to 182 days). Gram-positive cocci accounted for 56.7% of the episodes; gram-negative bacilli, for 42%. The most common microorganisms were coagulase-negative staphylococci (30.6%) and Pseudomonas aeruginosa (15.9%). MDR gram-negative bacilli caused 11.9% of all episodes. Clinical characteristics, source of BSI, etiology, and outcomes changed depending on time since HSCT. Globally, 26.6% of episodes were treated with inappropriate empiric antibiotic therapy, more frequently in BSI episodes caused by P. aeruginosa, MDR P. aeruginosa, and MDR gram-negative bacilli. The 30-day mortality was 19.2%. Independent risk factors for mortality were BSI occurring ≥30 days after HSCT (odds ratio [OR], 11.21; 95% confidence interval [CI], 4.63 to 27.19), shock (OR, 7.10; 95% CI, 2.98 to 16.94), BSI caused by MDR P. aeruginosa (OR, 4.45; 95% CI, 1.12 to 17.72), and inappropriate empiric antibiotic therapy for gram-negative bacilli or Candida spp. (OR, 3.73; 95% CI, 1.27 to 10.89). HSCT recipients experiencing BSI have high mortality related to host and procedure factors, causative microorganism, and empiric antibiotic therapy. Strategies to identify HSCT recipients at risk of MDR P. aeruginosa and reducing inappropriate empiric antibiotic therapy are paramount to reduce mortality.