224. Epidemiology of Bloodstream infections in a Cohort of Allogeneic Hematopoietic Stem Cell Transplant Patients from 2009 to 2018

BACKGROUND: Due to severe immunosuppression, patients undergoing allogeneic hematopoietic stem cell transplantation (aSCT) are at increased risk of infection and especially bloodstream infections (BSI) remain a major cause of death. Knowledge of the specific epidemiology of pathogens and resistances is of utmost importance to optimize antimicrobial treatment strategies. METHODS: Based on the Cologne Cohort of Neutropenic Patients (CoCoNut) database, we conducted a retrospective analysis of blood cultures collected within 100 days following transplantation of patients undergoing aSCT between January 2009 and December 2018 at the University Hospital of Cologne, Germany. Contamination of coagulase-negative Staphylococci (CoNS) isolates (single positive isolate within 5 days) was considered within the analysis. RESULTS: In total, 843 aSCT patients were available for analysis (484/843 [57%] male). The median age was 53 (interquartile range [IQR] 43–62) years, predominant underlying diseases were acute myeloid leukemia (47%, 397/843), lymphoma (14%, 117/843), and acute lymphoblastic leukemia (11%, 89/843). Median inpatient stay was 39 (IQR 34–50) days, while 67/843 (8%) patients died. Antibacterial prophylaxis was administered in 289/843 (34%) and antifungal prophylaxis in 738/843 (88%) patients. BSI was diagnosed in 233/843 (28%) patients. In total, 5,489 pairs of blood cultures were taken (median 4 per patient, IQR 2–8), while a pathogen could only be detected in 922/5,489 (17%). Most frequent pathogens were CoNS (259/922, 28%), Enterococcus spp. (219/922, 24%), E. coli (132/922, 14%), Klebsiella spp. (44/922, 5%), P. aeruginosa (39/922, 4%), S. aureus (37/922, 4%), and Candida spp. (42/922, 5%). Polymicrobial infection was detected in 58/922 (6%) cases. Within Enterococci isolates, 24/219 (11%) were VRE. None of the Klebsiella, but 9/132 (7%) of E. coli isolates were ESBL positive. In 4/37 (11%) cases S. aureus isolates were MRSA. CONCLUSION: Patients in the early phase after aSCT are at high risk of BSI with a predominantly gram-positive spectrum. Empirical antimicrobial treatment must consider pathogen epidemiology and resistance patterns while waiting for blood culture results. DISCLOSURES: All authors: No reported disclosures.