Background Prophylaxis with trimethoprim-sulfamethoxazole (TMP/SMP) is highly effective for the prevention of Pneumocysitis pneumonia (PCP) and recommended in patients with connective tissue diseases (CTD) undergoing high-dose corticosteroid therapy. Prophylaxis with TMP-SMZ is also reported to reduce the incidence of bloodstream infection with little discernible effect on the microflora in renal transplant but not studied in CTD. 
Objectives To investigate the predictors of bloodstream infection including prophylaxis of TMP-SMZ in patients with CTD undergoing high-dose corticosteroid therapy
Methods This is a retrospective cohort study. Patients with various CTD who fulfilled the following criteria were included: (1) patients were admitted to Tokyo Metropolitan Tama Medical Center between April 2008 and March 2013, (2) treatment with more than 50mg/day of prednisolone (PSL) was started after admission. Prophylaxis with TMP/SMX was 80mg of trimethoprim and 400mg of sulfamethoxazole. A half dose was also accepted. We classified patients into three group: “continued”, “discontinued”, and “no” prophylaxis with TMP/SMP against PCP. We analyzed the frequency and the characteristics of bloodstream infection for 24 weeks after starting high-dose corticosteroid and the predictors of bloodstream infection using univariate and multivariate analysis.
Results Among 170 patients analyzed, “continued”, “discontinued”, and “no” prophylaxis with TMP/SMP against PCP were 113, 41, and 16 respectively. The reasons of discontinuation were cytopenia (8), hyperkalemia (5), abnormal liver function (3), diarrhea (2), and abnormal renal function (1). (Table 1) Two patients developed PCP: 1 in “continued” and 1 in “discontinued”.
Total 10 Bloodstream infections were found: 2 (1.8%) in “continued”, 5 (12.2%) in “discontinued”, and 3 (18.8%) in “no” prophylaxis group. Six were catheter-related blood stream infection. Detected microorganisims were Methicillin-Resistant Staphylococcus epidermidis (4), Candida species (2), Escherichia coli (1), Klebsiella pneumoniae (1), Listeria monocytogenes (1), and α-streptococcus species (1) (Table 2).
By univariate and multivariate analysis, central venous catheter use was strongly predicted bloodstream infection (AOR 17.8). In contrast, “continued” prophylaxis with TMP/SMP was protective compared to “discontinued” or “no” prophylaxis.: AOR of “no” vs “continued” was 8.98 and AOR of “discontinued” vs “continued” prophylaxis was 19.0.
Conclusions Prophylaxis with TMP-SMZ against PCP may reduce the risk of bloodstream infection in patients with CTD undergoing high-dose corticosteroid therapy.
Ogawa J, et al. Prediction of and prophylaxis against Pneumocystis pneumonia in patients with connective tissue diseases undergoing medium- or high-dose corticosteroid therapy. Mod Rheumatol. 2005;15:91-6.
Fox BC, et al. A prospective, randomized, double-blind study of trimethoprim-sulfamethoxazole for prophylaxis of infection in renal transplantation: clinical efficacy, absorption of trimethoprim-sulfamethoxazole, effects on the microflora, and the cost-benefit of prophylaxis. Am J Med. 1990;89:255-74.
Acknowledgements Dr Yokogawa and Dr Kobayashi contributed equally to the study.
Disclosure of Interest : None declared