Background: S. maltophilia is a multi-drug resistant gram-negative opportunistic pathogen associated with discordant empiric therapy. Most S. maltophilia isolates are susceptible to trimethoprim-sulfamethoxazole (TMP-SMX) and levofloxacin (LVX) by in vitro sensitivity testing, but their relative effectiveness in S. maltophilia bacteremia remains unclear.
Methods: Clinical characteristics, in vitro activity and antibiotic therapy were examined for inpatients with S. maltophilia bacteremia in the Cerner Healthfacts database. Treatment was considered targeted if administered within 5 days after S. maltophilia isolation, and empiric if administered 1-5 days prior to isolation. Excluding resistant isolates, modified Poisson regression was used to estimate the adjusted relative risk (aRR) of therapy choice on mortality, controlling for empiric use, patient and facility-level factors.
Results: Of 171,909 patients with bacteremia from 2000-14, 660 (0.4%) at 102 hospitals had S. maltophilia; 99% of bloodstream isolates were susceptible to TMP-SMX and 97% to FQs. S. maltophilia bacteremia occurred more frequently in patients at >200 bed, urban and teaching hospitals. Nearly a third had ICU stays and over a third had central venous catheters. Of 600 evaluable patients, 122 (20%) received targeted therapy with TMP-SMX and 107 (18%) with LVX; more patients received targeted LVX in 2010-14 vs. 2005-09 and vice versa for TMP-SMX. Median age, SOFA scores, Elixhauser comorbidity index and % ICU were comparable between groups. Crude in-hospital mortality was higher in those receiving targeted TMP-SMX (17%) vs LVX (14%). In adjusted models, mortality risk was 3-fold greater in recipients of targeted TMP-SMX vs LVX (aRR=2.9 [1.4-5.8])and remained significant (aRR=3.4 [1.1-10.0]) upon excluding recipients of empiric therapy with TMP-SMX or FQ.
Conclusion: In a multicenter cohort of patients with S. maltophilia bacteremia, targeted treatment with LVX was associated with a lower relative risk of mortality compared to TMP-SMX, even when these agents were initiated after identification of S. maltophilia in blood cultures.
Y. L. Lai,
E. Ricotta, None
J. P. Dekker, None
R. L. Danner, None
S. S. Kadri, None
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