Bacterium
Coxiella burnetii
Q fever, aerosol zoonosis, no vector needed
kok-see-EL-uh bur-NEH-tee-eye
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
Frequently asked questions
What is Coxiella burnetii?
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.
What is the Gram stain of Coxiella burnetii?
Coxiella burnetii is Gram negative.
What are the lab clues for Coxiella burnetii?
Lab clues for Coxiella burnetii include Obligate intracellular growth vocabulary, Spore-like environmental resistance concept, Phase I / phase II antigen serology vocabulary, and Very low infectious dose framing.
What is Coxiella burnetii commonly confused with?
Coxiella burnetii is commonly confused with Brucella species and Rickettsia species.
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.