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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

Frequently asked questions

What is Stenotrophomonas maltophilia?

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

What is the Gram stain of Stenotrophomonas maltophilia?

Stenotrophomonas maltophilia is Gram negative.

What are the lab clues for Stenotrophomonas maltophilia?

Lab clues for Stenotrophomonas maltophilia include Oxidase negative vocabulary (contrast with Pseudomonas), DNase positive concept, Lysine decarboxylase positive vocabulary, and Intrinsic carbapenem resistance framing.

What is Stenotrophomonas maltophilia commonly confused with?

Stenotrophomonas maltophilia is commonly confused with Pseudomonas aeruginosa and Burkholderia cepacia complex.

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 foundations - sourceNCBI Bookshelf: Medical Microbiology organism chapters - sourceCDC: CDC disease and public-health topic pages - source