From the Guidelines
Stenotrophomonas maltophilia infections should be treated with trimethoprim-sulfamethoxazole (TMP-SMX) as the first-line therapy, with alternative options including fluoroquinolones, minocycline, or combination therapy with ceftazidime and levofloxacin for patients with sulfa allergies. The treatment of S. maltophilia infections is challenging due to its natural resistance to many antibiotics, including carbapenems, most beta-lactams, and aminoglycosides 1.
Key Considerations
- S. maltophilia is a gram-negative bacterium that commonly causes healthcare-associated infections, particularly in immunocompromised patients.
- The bacterium is commonly found in aqueous environments and can colonize hospital equipment like ventilators and catheters.
- Infections typically manifest as pneumonia, bacteremia, or urinary tract infections.
- Prevention strategies include proper hand hygiene, contact precautions, and appropriate sterilization of medical equipment.
- Susceptibility testing is crucial for guiding therapy as resistance patterns can vary significantly between isolates.
Treatment Options
- Trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line treatment, typically dosed at 8-10 mg/kg/day (based on the trimethoprim component) divided into 2-3 doses for 7-14 days, depending on the infection site and severity.
- Alternative options for patients with sulfa allergies include fluoroquinolones (levofloxacin 750 mg daily), minocycline (100 mg twice daily), or combination therapy with ceftazidime and levofloxacin.
- The choice of antibiotic should be guided by susceptibility testing and local resistance patterns.
Infection Control Measures
- Contact precautions, including the use of gloves and gowns, should be implemented for all colonized patient encounters to reduce the risk of acquisition 1.
- Environmental cleaning and disinfection, including the use of disinfectant agents and meticulous cleaning, should be performed to reduce transmission of S. maltophilia 1.
- Education and training programs should be conducted to ensure that healthcare workers understand the importance of infection control measures and how to implement them effectively 1.
From the Research
Treatment Options for Stenotrophomonas maltophilia Infections
- Trimethoprim-sulfamethoxazole (SXT) is recognized as the first-line therapy for S. maltophilia infections, based on good in vitro activity and favorable clinical outcomes 2.
- Other treatment options include levofloxacin (LVX) and minocycline (MIN), although recent PK/PD studies question the current clinical breakpoints for these agents 2.
- Novel therapeutic options such as cefiderocol (FDC) and ceftazidime-avibactam plus aztreonam (CZA-ATM) are suggested, based on limited but promising clinical data 2.
- Combination therapy of SXT, LVX, MIN, or FDC, or monotherapy with CZA-ATM are recommended therapeutic options for severe-to-moderate S. maltophilia infections 2.
Mechanisms of Resistance
- Intrinsic resistance may be due to reduced outer membrane permeability or to the multidrug efflux pumps 3.
- Specific mechanisms of resistance such as aminoglycoside-modifying enzymes or the heterogeneous production of metallo-beta-lactamase have contributed to the multidrug-resistant phenotype displayed by this pathogen 3.
Alternative Treatment Options
- Ciprofloxacin, ceftazidime or ceftriaxone, and ticarcillin/clavulanate, alone or in combination with other antibiotics, may be considered as alternative options beyond co-trimoxazole 4.
- Fluoroquinolones and trimethoprim-sulfamethoxazole are commonly used as monotherapy to treat S. maltophilia bacteremia, with no difference in rates of 30-day clinical failure or mortality between the two treatment regimens 5.