PetriKey

Bacterium

Coxiella burnetii

Q fever, aerosol zoonosis, no vector needed

kok-see-EL-uh bur-NEH-tee-eye

Gram negativegram-negativeintracellularzoonosisaerosolspore-likefastidious

High-yield clue

Q fever from inhaled aerosols of livestock birth products (no arthropod vector needed for humans) is the classic Coxiella clue.

Overview

An obligate intracellular Gram-negative bacterium that causes Q fever; it forms a resistant spore-like small-cell variant and is typically acquired by inhaling aerosols from farm animals rather than by an arthropod bite.

Classification

  • Gram-negative
  • Coccobacillus
  • Coxiellaceae
  • Obligate intracellular
  • Spore-like small-cell variant

Lab & identification clues

  • Obligate intracellular growth vocabulary
  • Spore-like environmental resistance concept
  • Phase I / phase II antigen serology vocabulary
  • Very low infectious dose framing

Associations

  • Cattle, sheep, goat birthing-aerosol transmission vocabulary
  • Acute febrile pneumonia/hepatitis presentation vocabulary
  • Chronic Q fever endocarditis association

Commonly confused with

  • Brucella species
  • Rickettsia 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