Epidemiology and risk factors of bloodstream infections among adolescents and young adults with acute lymphoblastic leukaemia: An 11‐year retrospective cohort study

Abstract Adolescent and young adults (AYAs) belong to a unique category of patients diagnosed with acute lymphoblastic leukaemia (ALL). Bloodstream infection (BSI) is a leading cause of treatment‐related mortality in ALL patients. However, the epidemiology and risk factors for mortality from BSIs in AYA patients remain unclear. In this study, we analysed these aspects in AYAs patients and compared similarities and differences with children (<15 years old) and older adults (>39 years old). We analysed the pathogenic epidemiology, antibiotic resistance and BSI risk factors of 73 children, 180 AYAs, and 110 older adults with ALL in three comprehensive hospitals from January 2010 to August 2021. The data on BSIs in AYAs were compared to that of the other two groups. In this study, the epidemiology of BSIs in AYAs was similar to that of older adult patients. Concerning clinical characteristics, most AYAs and older adults with BSIs were in a relapsed or uncontrolled state (34.5% vs. 35.4%, p = 0.861). In terms of pathogen distribution, Gram‐negative bacteria (GNB) were the most common causative pathogens in AYAs and older adult groups. Extended‐spectrum beta‐lactamase (ESBL)‐producing bacteria were more commonly found in AYAs than in children (32.8% vs. 16.4%, p = 0.09). Regarding risk factors, the length of hospitalization (>14 days) and renal inadequacy (creatinine ≥ 177 μmol/L) were influencing factors for 30‐day mortality in AYAs patients with BSIs. In our study, AYA patients with BSIs showed clinical characteristics and pathogen distributions similar to those of older adult patients but quite different from those of children.