DurgicalDurgical
EN
Open the app

Microbiology · Other Gram-negative rods

Bartonella !

  • Bacterium
  • Gram-negative
  • Exam priority: medium

Bacteria carried by cats, sand flies and lice. B. henselae causes cat scratch disease; B. bacilliformis causes Andean Carrión disease.

Updated 2026-11-01

Also called: Bartonella henselae, Bartonella bacilliformis, Bartonella quintana

At a glance

Gram
Gram-negative
Shape
Small curved rod
Oxygen
Aerobic, fastidious
Family
Bartonellaceae
Stain
Warthin-Starry (silver) in tissue; Giemsa inside red cells (B. bacilliformis)

Morphology

  • Small, very slow-growing Gram-negative rods
  • Facultative intracellular: infect red cells and endothelial cells
  • Cultures are held for weeks before being called negative

Transmission

  • B. henselae: cat scratch or bite (mainly flea-infested kittens); fleas pass it between cats
  • B. bacilliformis: bite of sand flies (Lutzomyia) in Andean valleys
  • B. quintana: body louse feces

Reservoir: Cats (B. henselae); Humans (B. bacilliformis and B. quintana)

Vector: Lutzomyia sand flies (B. bacilliformis), cat fleas (B. henselae) and body lice (B. quintana).

Isolation precautions

What the care team adds to standard precautions.

  • Standard

Virulence factors

  • Invades red cells: in Oroya fever it destroys many and causes severe hemolytic anemia
  • Drives new vessel growth (angiogenesis): verruga peruana and bacillary angiomatosis
  • Survives inside cells and evades the immune response

Diseases it causes

  • Cat scratch disease (B. henselae)
  • Carrión disease: Oroya fever (acute) and verruga peruana (chronic) from B. bacilliformis
  • Culture-negative endocarditis (B. henselae and B. quintana) Infective endocarditis →

Clinical picture

  • Cat scratch: a papule at the wound and, weeks later, large tender regional nodes; sometimes Parinaud oculoglandular syndrome
  • Oroya fever: fever, hemolytic anemia, jaundice and risk of added infections (such as Salmonella); high mortality untreated
  • Verruga peruana: red vascular skin nodules that bleed easily
  • In advanced HIV: bacillary angiomatosis and peliosis hepatis; trench fever from B. quintana

Diagnosis

  • Cat scratch: serology (immunofluorescence) or PCR; lymph node biopsy with granulomas
  • Oroya fever: blood smear with bacilli inside red cells, prolonged blood culture or PCR
  • Verruga peruana: clinical picture and biopsy
  • Endocarditis: serology and valve PCR

Treatment

Cat scratch: usually self-limited; a macrolide (azithromycin) may shorten the node swelling. Oroya fever: fluoroquinolones (ciprofloxacin) with third-generation cephalosporins (ceftriaxone), or chloramphenicol with a beta-lactam. Verruga peruana: macrolides or rifampicin. Bacillary angiomatosis: macrolides or doxycycline.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

Prevention

  • Flea control in cats and washing scratches
  • Repellents, protective clothing and bed nets against sand flies in Andean areas
  • Personal hygiene and lice control

Test yourself

Think of the answer, then tap the question to see it.

Which Bartonella species causes Carrión disease, and how is it spread?

Bartonella bacilliformis, through the bite of Lutzomyia sand flies in Andean valleys.

What are the two phases of Carrión disease?

Oroya fever, acute, with hemolytic anemia, and verruga peruana, chronic, with vascular skin nodules.

Which vascular lesion does B. henselae cause in advanced HIV?

Bacillary angiomatosis.

How is Oroya fever diagnosed in the clinical lab?

With a blood smear showing bacilli inside red cells, plus prolonged blood cultures or PCR.

Where was Carrión disease described in Colombia?

In the Guáitara River valley, Nariño, in 1939.

Add to my cards (5)

← Back to the group: Other Gram-negative rods

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: About Bartonella (CDC, 2026); Clinical Overview of Bartonella bacilliformis (CDC, 2026); Oroya Fever and Verruga Peruana (MSD Manual Professional Edition, 2026); Oroya Fever, Verruga Peruana, and Other Bartonelloses Incidence Rates in Colombia (2009-2013) (Cureus (PMC), 2018).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.