Risk factors for mortality in patients with bloodstream infections during the pre-engraftment period after hematopoietic stem cell transplantation

BACKGROUND: Bloodstream infections (BSI) remain a frequent complication during the pre-engraftment period after hematopoietic stem cell transplantation (HSCT), resulting in high mortality rates. This study evaluated risk factors for mortality in hematopoietic stem cell transplant recipients with BSI in the pre-engraftment period. METHODS: This prospective case control study was performed at the Center of Hematology and Bone Marrow Transplantation in Minsk, Republic of Belarus. Data relating to patient age and gender, date and type of transplantation, conditioning chemotherapy regimen, microorganisms isolated from blood, and antibacterial therapy were prospectively collected from all hematopoietic stem cell recipients with microbiologically proven cases of BSI in the pre-engraftment period. The primary outcome was all-cause 30-day mortality after onset of febrile neutropenia. RESULTS: A total of 135 adult patients with microbiologically proven BSI after HSCT were studied, with 65.2% of cases caused by gram-negative microorganisms and 21.5% by non-fermenting bacteria. Inadequate empiric antibacterial therapy and isolation of carbapenem-resistant non-fermenting gram-negative bacteria (Acinetobacter baumannii and Pseudomonas aeruginosa) were independently associated with increased all-cause 30-day mortality in these patients. CONCLUSION: The risk factors for mortality in adult patients with BSI in the pre-engraftment period after HSCT were inadequacy of empirical antibacterial therapy and isolation of carbapenem-resistant A. baumannii or P. aeruginosa.