Stenotrophomonas — SCE Infectious Diseases MCQ

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ModerateAntimicrobial StewardshipStenotrophomonasSCE Infectious Diseases

A 60-year-old man develops severe sepsis from an infected diabetic foot ulcer. Blood cultures grow a Gram-negative rod identified as Stenotrophomonas maltophilia. The organism is intrinsically resistant to Meropenem. What is the most appropriate antibiotic?

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Correct answer: C — Co-trimoxazole IV/oral high dose

Stenotrophomonas maltophilia is intrinsically resistant to carbapenems (particularly Meropenem and Imipenem) due to production of L1 and L2 beta-lactamases. Co-trimoxazole is the treatment of choice and is the only agent with consistent activity. Alternatives include Ticarcillin/Clavulanate (limited availability), Minocycline, Levofloxacin, or Ceftazidime/Avibactam (variable activity). Stenotrophomonas typically causes nosocomial infections in debilitated or immunocompromised patients.

Reference: BSAC 2023 – MDR Gram-negative treatment; EUCAST 2024 – Intrinsic resistance