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Bacterium

Francisella tularensis

Tularemia, rabbit/tick zoonosis, cysteine need

fran-sih-SEL-uh too-lah-REN-sis

Gram negativegram-negativecoccobacilluszoonosisintracellulartick-borneselect-agent

High-yield clue

Tularemia ('rabbit fever') is a fastidious, cysteine-requiring intracellular coccobacillus spread by ticks, deerflies, and rabbit contact.

Overview

A highly infectious, fastidious Gram-negative coccobacillus that is a facultative intracellular pathogen and the cause of tularemia, a high-yield zoonotic select-agent study organism.

Classification

  • Gram-negative
  • Coccobacillus
  • Francisellaceae
  • Aerobe
  • Facultative intracellular

Lab & identification clues

  • Cysteine-requiring growth vocabulary
  • Fastidious, slow-growing concept
  • Very low infectious dose vocabulary
  • Serology-based identification concept

Associations

  • Ticks, deerflies, and rabbit/rodent contact vocabulary
  • Ulceroglandular presentation vocabulary
  • Category A select-agent and aerosol-risk framing

Commonly confused with

  • Yersinia pestis
  • Brucella species

Frequently asked questions

What is Francisella tularensis?

A highly infectious, fastidious Gram-negative coccobacillus that is a facultative intracellular pathogen and the cause of tularemia, a high-yield zoonotic select-agent study organism.

What is the Gram stain of Francisella tularensis?

Francisella tularensis is Gram negative.

What are the lab clues for Francisella tularensis?

Lab clues for Francisella tularensis include Cysteine-requiring growth vocabulary; Fastidious, slow-growing concept; Very low infectious dose vocabulary; Serology-based identification concept.

What is Francisella tularensis commonly confused with?

Francisella tularensis is commonly confused with Yersinia pestis and Brucella 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.

OpenStax: Microbiology 2e organism classification foundations - sourceNCBI Bookshelf: Medical Microbiology organism chapters - sourceCDC: CDC disease and public-health topic pages - source