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

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