PetriKey

Bacterium

Legionella pneumophila

Water-associated intracellular rod

lee-juh-NEL-uh noo-MOH-fih-luh

Gram negativebacteriagram-negativerodwaterintracellularrespiratory

High-yield clue

Water system exposure vocabulary + atypical pneumonia teaching clue.

Overview

A water-associated bacterium used to teach atypical pneumonia vocabulary, intracellular survival concepts, and outbreak investigation framing.

Classification

  • Gram-negative
  • Rod
  • Intracellular survival concept

Lab & identification clues

  • Poor Gram-stain visibility in teaching examples
  • Urinary antigen vocabulary
  • Buffered charcoal yeast extract is a term to recognize, not a protocol

Associations

  • Atypical pneumonia vocabulary
  • Cooling-tower/outbreak framing
  • Intracellular pathogen concept

Commonly confused with

  • Mycoplasma pneumoniae
  • Streptococcus pneumoniae

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