Epidemiology, resistant pathogens, and causes of early death in cases of bloodstream infection in patients with hematological malignancies from 2012-2019

Purpose: To investigate the epidemiology, causative pathogen antibiotic susceptibility, and mortality risk factors of bloodstream infection (BSI) in patients with hematological malignancies (HMs).

Methods: Single-center retrospective analysis of BSI cases in patients with HMs in a Chinese tertiary hospital from 2012-2019.

Results: Among 17,796 analyzed admissions, 508 BSI episodes (2.9%; 95% confidence interval: 2.6%-3.2%) were identified. Of 522 resulting isolates, 326 (62.5%) were Gram-negative, 173 (33.1%) were Gram-positive. The BSI incidence among patients with different HMs (severe aplastic anemia: 6.7%; acute leukemia: 6.2%; myelodysplastic syndrome: 3.2%; multiple myeloma: 1.3%; and lymphoma: 1.0%) differed significantly (p < 0.001). The BSI incidence was significantly higher in the hematopoietic stem cell transplantation (HSCT) group (10.2%) than in the non-HSCT group (2.5%; p < 0.001). Escherichia coli (30.7%, 160/522) was the most common pathogen, followed by Coagulase-negative staphylococci (19.4%, 101/522) and Klebsiella pneumoniae (10.0%, 52/522)., The rates of imipenem resistance for E. coli, K. pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii were 6.4%, 15.0%, 27.8%, and 79.0%, respectively. All the Gram-positive pathogens were linezolid susceptible. Three vancomycin-resistant Enterococcus species were isolated. The overall 14-day mortality was 9.8% (95% confidence interval: 7.2%-12.4%). A multivariate analysis showed that HM subtype severe aplastic anemia, A. baumannii, and malignancy non-remission were independent 14-day mortality risk factors.

Conclusions: Gram-negative bacteria were the most common pathogens, with E. coli as the predominant strain, causing BSIs in HM patients. A carbapenem-resistant A. baumanni with a high mortality rate in HM patients made empirical antimicrobial choice a highly challenging issue.