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PetriKey

Bacterium

Bartonella henselae

Cat-scratch disease, bacillary angiomatosis

bar-toh-NEL-uh hen-SEL-eye

Gram negativegram-negativerodzoonosisfastidiousintracellularcat-associated

High-yield clue

Regional lymphadenopathy after a kitten scratch (cat-scratch disease) is the classic Bartonella henselae clue; bacillary angiomatosis appears in immunocompromised hosts.

Overview

A fastidious Gram-negative rod studied as the cause of cat-scratch disease and, in immunocompromised hosts, of vascular proliferative lesions such as bacillary angiomatosis.

Classification

  • Gram-negative
  • Rod
  • Bartonellaceae
  • Aerobe
  • Fastidious intracellular

Lab & identification clues

  • Warthin-Starry silver stain vocabulary
  • Fastidious, hard-to-culture concept
  • Serology/PCR-based identification vocabulary
  • Facultative intracellular growth concept

Associations

  • Kitten scratch/bite and cat-flea transmission vocabulary
  • Regional lymphadenopathy presentation vocabulary
  • Bacillary angiomatosis in immunocompromised hosts framing

Commonly confused with

  • Pasteurella multocida
  • Coxiella burnetii

Frequently asked questions

What is Bartonella henselae?

A fastidious Gram-negative rod studied as the cause of cat-scratch disease and, in immunocompromised hosts, of vascular proliferative lesions such as bacillary angiomatosis.

What is the Gram stain of Bartonella henselae?

Bartonella henselae is Gram negative.

What are the lab clues for Bartonella henselae?

Lab clues for Bartonella henselae include Warthin-Starry silver stain vocabulary; Fastidious, hard-to-culture concept; Serology/PCR-based identification vocabulary; Facultative intracellular growth concept.

What is Bartonella henselae commonly confused with?

Bartonella henselae is commonly confused with Pasteurella multocida and Coxiella burnetii.

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