Objective: To identify risk factors for developing drug-resistant bacterial infections in patients with systemic lupus erythematosus (SLE).
Methods: A retrospective, case-control study was performed. Patients fulfilled American College of Rheumatology criteria for SLE and had an episode of bloodstream infection between 2001 and 2012. Cases were defined as those with bloodstream infection caused by drug-resistant bacteria (Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, or extended-spectrum-β-lactalamase-producing Escherichia coli); while controls had susceptible strains of S. aureus or E. coli. Differences between groups were analyzed by Student t test or Mann-Whitney U test. Association between variables was assessed by OR (CI 95%). Multivariate analysis was performed by binary logistic regression model.
Results: Forty-four patients were included in each group. Variables associated with drug-resistant bloodstream infection were history of central nervous system activity; hematological activity, immunosuppressive treatment and prednisone dose at the time of the infection; and low C3 levels, antibiotic use, or hospitalization in the previous 3 months. In multivariate analysis, variables that remained significant were low C3 previous to infection (OR 3.12, CI 95% 1.91-8.22), previous hospitalization (OR 2.22, CI 95% 1.42-4.10), and prednisone dose at the time of infection (OR 1.10, CI 95% 1.04-1.22).
Conclusion: Low C3 levels, recent hospitalization, and prednisone dose at time of infection are independent risk factors for acquiring drug-resistant bacteria in patients with SLE. Although the present data do not fully support a change in initial treatment-decision strategies, this information could lead to prospective studies designed to address this issue, which could determine the best approach in clinical practice.
Keywords: BACTEREMIA; BACTERIAL DRUG RESISTANCE; COMPLEMENT SYSTEM PROTEINS; GLUCOCORTICOIDS; INFECTION; SYSTEMIC LUPUS ERYTHEMATOSUS.