Treatment of Multi-Drug Resistant Stenotrophomonas maltophilia Bacteremia
High-dose trimethoprim-sulfamethoxazole (TMP-SMX) at 15-20 mg/kg/day of the trimethoprim component is the first-line treatment for multi-drug resistant Stenotrophomonas maltophilia bacteremia. 1, 2
First-Line Treatment
- TMP-SMX remains the preferred agent for documented S. maltophilia infections, including bacteremia, with strong evidence supporting its efficacy 1
- Dosing should be high-dose (15-20 mg/kg/day of trimethoprim component) to ensure adequate coverage against resistant strains 1
- Treatment should be initiated promptly when S. maltophilia bacteremia is documented to prevent poor outcomes, particularly in immunocompromised patients 1
- Duration of therapy should be at least 14 days for bloodstream infections in immunocompromised patients 1
Alternative Treatment Options for TMP-SMX Resistant Strains
- Levofloxacin 750 mg daily can be used for severe infections when the organism is susceptible and the patient cannot tolerate TMP-SMX 2
- Minocycline has shown good in vitro activity and can be considered as an alternative agent 3, 4
- Tigecycline-based treatment is an appropriate alternative with documented efficacy, though with less supporting evidence 1
- Recent data suggests cefiderocol may be effective against multi-drug resistant strains 3
- Ceftazidime-avibactam plus aztreonam combination has shown promising results in limited clinical data 3
Combination Therapy Considerations
- The latest guidance from the Infectious Diseases Society of America recommends using agents like TMP-SMX, levofloxacin, and minocycline as part of combination therapy for severe infections 3
- Combination therapy should be considered for severe bacteremia cases, especially in immunocompromised patients 3
- Options for combination include TMP-SMX plus levofloxacin or TMP-SMX plus minocycline 3
Special Considerations for Bacteremia
- For catheter-related bloodstream infections, catheter removal should be considered in addition to antimicrobial therapy 1
- In vitro susceptibility testing should guide therapy, though it's essential to note that in vitro susceptibility may not always predict clinical efficacy 1, 5
- Recent pharmacodynamic studies question current clinical breakpoints for TMP-SMX against S. maltophilia, suggesting higher doses may be needed 5, 6
Monitoring and Pitfalls
- Monitor for TMP-SMX resistance, which is an increasing problem globally 7
- TMP-SMX may have limited activity against some strains even when they appear susceptible in vitro 5, 6
- Adverse effects of high-dose TMP-SMX (including bone marrow suppression, hyperkalemia, and nephrotoxicity) should be monitored, especially in critically ill patients 1
- Recent in vitro studies suggest that TMP-SMX may not achieve adequate killing against S. maltophilia compared to other organisms at the same MIC, highlighting the importance of appropriate dosing 6