Data collection and Definitions
Sex, age, underlying diseases, presence of diabetes mellitus, length of hospitalization, clinical laboratory values ( white blood cell counts, absolute neutrophil and platelet counts, and hemoglobin levels) at the same time or within 24h of BC, neutropenia duration prior to obtaining any BC, disease status, strains of pathogenic bacteria and resistance to antibiotics, and antibiotic therapy type(s) were extracted from the charts. Prior antimicrobial exposure was defined as the presence of any previous history of antibiotics for over 48 hours within 1 month. We used the definitions proposed by Kameda et al. to define definite or probable BSI.[26] Briefly, ”definite BSI” was defined as the isolation of at least one BC of a bacterial or fungal pathogen other than common skin contaminants. For common skin contaminants such as diphtheroids, Bacillus spp., Propionibacterium spp., coagulase-negative Staphylococci, viridans streptococci, Aerococcus spp., and Micrococcus spp., detection in two or more separate blood cultures is required for a definite BSI diagnosis. [27 28] Neutropenia and profound neutropenia were defined as an absolute neutrophil count (ANC) of <500 cells/mm3 and <100 cells/mm3, respectively.[29] MDR bacteria were defined as those that were resistant to three or more classes of antibiotics.[30] Acute respiratory failure and acute renal failure have been described by Tang et al.[31] Antibiotic exposure was defined as any antimicrobial therapy lasting more than 48h in the previous month.[32]Inappropriate initial antimicrobial therapy (IIAT) refers to antibiotic regimens prescribed and administered during the first 72h after suspecting BSI, and is not active against the pathogen identified by culture and in vitro susceptibility testing.[31 33]