PetriKey

Bacterium

Morganella morganii

Urease- and indole-positive nosocomial enteric rod

mor-guh-NELL-uh mor-GAN-ee-eye

Gram negativegram-negativerodentericureaseamrnosocomial

High-yield clue

A urease-positive, indole-positive Enterobacterales rod causing catheter-associated/nosocomial UTI is the core study clue.

Overview

A Gram-negative enteric rod in the order Enterobacterales, historically grouped with the Proteae tribe (Morganellaceae). It is an opportunistic pathogen most often linked to healthcare-associated urinary tract and wound infections.

Classification

  • Gram-negative
  • Rod
  • Enterobacterales
  • Morganellaceae (Proteae tribe)
  • Facultative anaerobe

Lab & identification clues

  • Urease positive vocabulary
  • Indole positive (contrast Proteus mirabilis, indole negative)
  • Inducible AmpC beta-lactamase framing
  • Lactose non-fermenter on MacConkey

Associations

  • Healthcare-associated UTI study association
  • Catheter-associated and postoperative wound infection
  • Opportunistic infection in comorbid hosts
  • Intrinsic/acquired antimicrobial-resistance framing

Commonly confused with

  • Proteus mirabilis
  • Providencia species

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