Stenotrophomonas maltophilia

Background

Microbiology

• Aerobic, non-fermentive, catalase positive, oxidase negative, Gram-negative bacillus
• Multiple mechanisms of resistance
  • RND, MfsA, and Sme-related efflux pumps
  • Sul or dfrA genes (TMP-SMX resistance)
  • β-lactamases
  • Aminoglycoside-modifying enzymes

Clinical Manifestations

• Nosocomial infections with high mortality and high antibiotic resistance

Management

• Limited antibiotic options
• Therapy should be guided by antimicrobial susceptibility testing
• Antistenotrophomonal antibiotics:
  • TMP-SMX 15 mg/kg split q8h (preferred agent, if susceptible)
  • Fluoroquinolones, including moxifloxacin, levofloxacin, and ciprofloxacin (though develops resistance quickly on monotherapy)
  • Minocycline, doxycycline, and tigecycline
  • Ticarcillin-clavulanate and ampicillin-sulbactam
  • Ceftazidime and ceftazidime-avibactam
  • Colistin, though high rates of resistance
  • Possibly ceftriaxone