Study design
Data were extracted from the medical records of patients admitted to three university-affiliated tertiary care hospitals in Hunan Province, China, from January 2010 to August 2021. All three hospitals admitted both child and adult patients, with a comparable number of patients and testing techniques, ensuring that there was no difference in ALL demographic and BSI epidemiological data. A flowchart of patient selection is shown in Fig.1. Inclusion criteria included diagnosis of ALL, treatment with chemotherapy, and available blood culture (BC) data. If the patient had two or more positive BC, the clinical data associated with the first positive BC during the same hospitalization were included. Patients who did not meet the inclusion criteria were excluded from this study. Blood culture samples showing different bacterial strains within 48h were defined as poly microbial bacteria and were excluded from the study due to the limited sample volume (N=13), as were patients who were lost to follow-up (N=8) and blood culture contamination (N=15). We further excluded patients with a history of hematopoietic stem cell transplantation (HSCT) (N=11). Finally, information regarding blood culture-positive patients was obtained, and the use of antimicrobial therapy was recorded. The primary outcome was survival or death on day 30 of follow-up.