To investigate the risk factors and bacteriological distribution of bloodstream infection in patients with systemic lupus erythematosus (SLE).

The clinical data, laboratory examination, and treatment of SLE patients hospitalized at the Rheumatology Department of Shanxi Bethune Hospital from January 2014 to January 2022 were collected. The patients were divided into either an experimental group or a control group based on the presence of bloodstream infection or not. The experimental group included 21 SLE patients with bloodstream infection, and the control group included 42 SLE patients without bloodstream infection that were randomly matched according to age and gender at a ratio of 1∶2. The demographic data, clinical and laboratory baseline characteristics, SLE activity index (SLEDAI), complications, hormone and immunosuppressant use, and etiological data were compared between the two groups. Multivariate logistic regression analysis was used to identify the risk factors for bloodstream infection in SLE patients.

Of the 21 patients with bloodstream infection, 4 (19%) had initial SLE. In the univariate analysis, neutrophil count was higher, lymphocyte count was lower, serum creatinine was higher, serositis was more common, and average hormone dosage was higher (≥12.5 mg/d) in the past 3 months in the bloodstream infection group than in the non-bloodstream infection group (P＜0.05 for all). All variables with a statistical difference in the univariate analysis were included in the final multivariate logistic regression analysis, and the results showed that decreased lymphocyte count (odds ratio [OR]=13.070, 95% confidence interval [CI]:1.535-111.285, P=0.019) and serositis (OR=0.208, 95%CI: 0.050-0.867, P=0.031) were risk factors for bloodstream infection in SLE patients. Regarding the bacteriological distribution of bloodstream infections in 21 SLE patients, the most common pathogens were Escherichia coli, Staphylococcus aureus, and Salmonella, and the infection locations were the urinary tract, lungs, and gastrointestinal tract, respectively. Three patients in the bloodstream infection group died, including one case of Cryptococcus infection combined with intracranial infection, one case of Escherichia coli infection combined with Epstein-Barr virus infection, and one case of Listeria monocytogenes infection combined with brain abscess.

In clinical practice, for SLE patients with lymphocytopenia and serositis, if fever and other infection symptoms occur, vigilance should be raised for blood infection, and timely blood culture and antibiotic treatment should be carried out to improve the prognosis.