Epidemiology, resistant pathogens and main causes of early death of bloodstream infection in patients with hematological malignancies from 2012 to 2019 in a Chinese tertiary hospital

Background: To investigate epidemiology, antibiotic-susceptibility of pathogens, and risk factors for mortality of bloodstream infection (BSI) in patients with hematological malignancies (HMs). Methods: Single-centre retrospective analysis of BSI episodes in patients with HMs in a Chinese tertiary hospital from 2012 to 2019. Results: Among 17,796 analyzed admissions, 508 BSI episodes (2.85%) were identified. Of the 522 isolates, 326 (62.45%) were Gram-negative bacteria, 173 (33.14%) were Gram-positive bacteria, and 23 (4.41%) were fungi. The incidence of BSI differed significantly among the patients with different HMs (P = 0.000): severe aplastic anemia (6.67%), acute leukemia (6.15%), myelodysplastic syndrome(3.22%), multiple myeloma (1.29%), and lymphoma (1.02%). Escherichia coli (30.65%, 160/522) was the most common pathogens, followed by Coagulase-negative staphylococci (CoNS) (19.35%, 101/522) and Klebsiella pneumonia （9.96%, 52/522) . The resistance rates of E. coli , K. pneumonia , P. aeruginosa , and A. baumannii to carbapenems were 6.42%, 15.00%, 27.78%, and 78.95%, respectively. All the Gram-positive pathogens were susceptible to linezolid, and 3 vancomycin-resistant Enterococcus were isolated. The overall 14-day mortality was 9.84%. The mortality of BSI caused by A. baumannii was 73.86%, while caused by other pathogens was 7.36% (p=0.000). A multivariate analysis showed that age >65 years, A. baumannii and non-remission of the malignancy were independent predictors of 14-day mortality. Conclusion: Gram-negative bacteria continued to be the most common pathogens causing BSIs in HM patients. An extensive multi-drug resistant baumanni with high mortality rate in HM patients made empirical antimicrobial choice a highly challenging issue.