What antibiotic will cover Methicillin-resistant Staphylococcus aureus (MRSA) and Stenotrophomonas?

Antibiotics for MRSA and Stenotrophomonas Infections

For infections involving both MRSA and Stenotrophomonas, trimethoprim-sulfamethoxazole (TMP-SMX) is the most effective antibiotic that provides coverage against both pathogens. 1

MRSA Coverage Options

Oral Options for MRSA

• TMP-SMX (1-2 double-strength tablets twice daily) - first-line oral option for coverage of both organisms 1
• Linezolid (600mg twice daily) - excellent MRSA coverage but limited activity against Stenotrophomonas 1
• Tetracyclines (doxycycline 100mg twice daily or minocycline 100mg twice daily) - effective against many MRSA strains but variable activity against Stenotrophomonas 1
• Clindamycin (300-450mg three times daily) - effective for some MRSA but ineffective against Stenotrophomonas and has high rates of resistance (up to 50% of MRSA strains have inducible or constitutive resistance) 1

Intravenous Options for MRSA

• Vancomycin (15-20mg/kg IV every 8-12 hours) - standard IV therapy for MRSA but no activity against Stenotrophomonas 1
• Daptomycin (10mg/kg/day IV once daily) - effective for MRSA but no activity against Stenotrophomonas 1
• Linezolid (600mg IV twice daily) - excellent MRSA coverage 1, 2
• Ceftaroline (600mg IV every 12 hours) - newer cephalosporin with MRSA activity 1, 2
• Dalbavancin, tedizolid, tigecycline - additional options for MRSA 1

Stenotrophomonas Coverage

• TMP-SMX - considered the drug of choice for Stenotrophomonas infections 1
• Fluoroquinolones (levofloxacin, ciprofloxacin) - variable activity against Stenotrophomonas 1
• Ticarcillin-clavulanate - historically used but now discontinued in many markets 1
• Minocycline - may have activity against some strains 1

Optimal Choice for Dual Coverage

Monotherapy Option

• TMP-SMX (1-2 double-strength tablets twice daily orally or 8-10mg/kg/day IV of the trimethoprim component divided every 8-12 hours) is the only reliable single agent that covers both MRSA and Stenotrophomonas 1

Combination Therapy Options

For severe infections where combination therapy is preferred:

• TMP-SMX plus minocycline 1
• TMP-SMX plus a glycopeptide (vancomycin or teicoplanin) for enhanced MRSA coverage in severe infections 1, 2

Clinical Considerations

• For skin and soft tissue infections involving both organisms, TMP-SMX is recommended as first-line therapy 1
• For severe infections (bacteremia, pneumonia), consider combination therapy or higher doses of TMP-SMX 1
• Monitor for TMP-SMX adverse effects including hyperkalemia, bone marrow suppression, and rash 1
• TMP-SMX is pregnancy category C/D and not recommended for women in the third trimester of pregnancy or children <2 months of age 1
• Consider local antibiogram data when selecting therapy, as resistance patterns may vary 1
• Therapeutic drug monitoring should be considered for vancomycin if used in combination therapy 1

Special Populations

• For patients with sulfa allergies, combination therapy with minocycline plus a fluoroquinolone may be considered, though efficacy against both pathogens may be suboptimal 1, 2
• In patients with renal insufficiency, dose adjustment of TMP-SMX is required 1
• For immunocompromised patients, higher doses of antibiotics and longer duration of therapy may be necessary 1