Abstract:

Objective To investigate the roles on early diagnosis and prognosis of neutrophil-lymphocyte ratio（NLR），C-reactive protein（CRP），procalcitonin（PCT），serum amyloid A（SAA），interleukin-6（IL-6）and CD64 index for bloodstream infection. Methods Totally，380 patients with bacterial bloodstream infection were enrolled as bloodstream infection group from Shanghai Ninth People's Hospital of Shanghai Jiao Tong University School of Medicine from January 2019 to June 2023. A total of 100 inpatients with negative blood culture were enrolled as control group. The NLR，CRP，PCT，SAA，IL-6 and CD64 index were determined. According to the types of infecting bacteria，the subjects were classified into Gram-positive（G⁺）bacterium group（105 cases）and Gram-negative（G^-）bacterium group（275 cases）. Among the 380 patients，210 patients were complicated by sepsis，which were classified into death group（40 cases）and survival group（170 cases）based on their survival status. Results The patients in G⁺ bacteria induced bloodstream infection were mainly from emergency department，general surgery department and general surgery intensive care unit，and Staphylococcus aureus，Enterococcus faecium and Staphylococcus epidermis were the main ones. The patients in G^- bacteria induced bloodstream infection were mainly from general surgery intensive care unit，general surgery department and hematology department，which were mainly composed of Escherichia coli，Klebsiella pneumoniae and Acinetobacter baumannii. The NLR，CRP，PCT，SAA，IL-6 and CD64 index in G⁺ and G^- bacterium groups were higher than those in control group（P<0.05）. The PCT，IL-6 and CD64 index in G^- bacterium group were higher than those in G⁺ bacterium group（P<0.05），and there was no statistical significance in NLR，CRP and SAA between the 2 groups（P>0.05）. The NLR，PCT，CRP，SAA，IL-6 and CD64 index in death group were higher than those in survival group（P<0.05）. Conclusions NLR，CRP，PCT，SAA，IL-6 and CD64 index have efficacy in the diagnosis and prognosis of bloodstream infection. PCT，IL-6 and CD64 index may distinguish infecting bacterial types in bloodstream infection.

Key words: Neutrophil-lymphocyte ratio, C-reactive protein, Procalcitonin, Serum amyloid A, Interleukin-6, CD64 index, Bloodstream infection, Bacterium