Comparisons between patients with trimethoprim-sulfamethoxazole-susceptible and trimethoprim-sulfamethoxazole-resistant Stenotrophomonas maltophilia monomicrobial bacteremia: A 10-year retrospective study.

Background/purpose The impact of bacteremia due to the resistance of Stenotrophomonas maltophilia to trimethoprim–sulfamethoxazole (TMP–SXT) is uncertain. This study compared the clinical characteristics and outcomes of patients with TMP–SXT-susceptible (TSSSM) and TMP–SXT-resistant S. maltophilia (TSRSM) monomicrobial bacteremia. Methods The medical records of adult patients with TSSSM and TSRSM monomicrobial bacteremia from January 2004 to December 2013 were reviewed and classified into two groups, namely, TSSSM and TSRSM. Results There were 184 patients with monomicrobial S. maltophilia bacteremia. The mean age was 68.3 years. Most patients were males (72.8%), had high Charlson Comorbidity Index scores, previously prescribed antimicrobial agents, and indwelling medical devices. The 14-day and in-hospital mortality rates were 23.9% and 47.2%, respectively. There were 128 patients (69.6%) with TSSSM and 56 (30.4%) with TSRSM. The incidence of TSSSM bacteremia increased during the study period. The TSSSM and TSRSM groups had similar demographic and clinical characteristics and no significant differences in 14-day and in-hospital mortality (24.2% vs. 23.2%, p  = 0.833; 50.0% vs. 41.1%, p  = 0.264, respectively). Patients with TSSSM bacteremia had an increased risk of septic shock ( p  = 0.044) and neutropenia ( p  = 0.028) at bacteremia onset. Logistic regression analysis indicated that acquisition of TMP–SXT resistance was an independent risk factor for prolonged hospitalization ( p  = 0.018) and catheter-related S. maltophilia bacteremia was inversely associated with prolonged hospitalization after bacteremia ( p  = 0.032). Conclusion There were no significant differences in mortality for patients with TSSSM and TSRSM bacteremia, but patients with TSRSM bacteremia were associated with prolonged hospitalization after bacteremia onset.