Clinical and microbiologic outcomes of Stenotrophomonas maltophilia bloodstream infections.

PURPOSE

The optimal treatment for infections due to Stenotrophomonas maltophilia has not been defined.

METHODS

This was a multicenter, retrospective study of patients with S. maltophilia bacteremia between March 2010 to December 2023. Patients > 18 years with a positive blood culture growing S. maltophilia were included. Patients treated < 48 h or those with central line colonization were excluded. Clinical failure was defined as emergence of resistance during treatment, recurrent S. maltophilia bacteremia or death within 30 days. Outcomes for those treated with fluoroquinolone or trimethoprim-sulfamethoxazole monotherapy were compared using a propensity scored-adjusted full matching approach.

RESULTS

217 patients were included; 17% (37/217) patients had a history of transplant. The clinical failure rate was 16% (35/217); reasons for failure included death (n = 22), recurrent bacteremia (n = 12) or treatment-emergent resistance (n = 3). One patient each with recurrence and resistance also died within 30 days. Within 90 days, resistance developed in 15 patients. The most common treatment regimens were fluoroquinolones (n = 103) and trimethoprim-sulfamethoxazole (n = 45) as monotherapy. Use of high-dose trimethoprim-sulfamethoxazole did not improve clinical success rates. Combination therapy was employed in 10% (21/217) of patients. After applying full-matching criteria, there was no difference in rates of 30-day clinical failure (aOR = 1.02; 95% CI 0.25-3.82; P = 0.999) or mortality (aOR = 1.4; 95% CI 0.25-7.25; P = 0.727) among patients treated with fluroquinolone or trimethoprim-sulfamethoxazole monotherapy.

CONCLUSION

Monotherapy with fluoroquinolones or trimethoprim-sulfamethoxazole were used most commonly to treat S. maltophilia bacteremia across centers. Patient outcomes did not differ between treatment regimens and the overall rate of treatment-emergent resistance was low.