PetriKey

Bacterium

Stenotrophomonas maltophilia

Multidrug-resistant nosocomial non-fermenter

sten-oh-troh-FOH-mo-nas mal-toh-FIL-ee-uh

Gram negativegram-negativerodnon-fermenteramrnosocomialbiofilm

High-yield clue

Non-fermenting Gram-negative rod that is oxidase negative and intrinsically resistant to carbapenems, unlike Pseudomonas.

Overview

An environmental non-fermenting Gram-negative rod studied as a healthcare-associated opportunist notable for broad intrinsic resistance, including to carbapenems.

Classification

  • Gram-negative
  • Rod
  • Xanthomonadaceae
  • Aerobe
  • Non-fermenter

Lab & identification clues

  • Oxidase negative vocabulary (contrast with Pseudomonas)
  • DNase positive concept
  • Lysine decarboxylase positive vocabulary
  • Intrinsic carbapenem resistance framing

Associations

  • Ventilator and catheter-associated infection vocabulary
  • Immunocompromised and prior broad-spectrum exposure risk
  • Multidrug-resistance public-health framing

Commonly confused with

  • Pseudomonas aeruginosa
  • Burkholderia cepacia complex

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource