[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other Gram-negative rods](https://durgical.com/en/microbiology/groups/other-gram-negative-rods/) › Bartonella [Microbiology](https://durgical.com/en/microbiology/) · [Other Gram-negative rods](https://durgical.com/en/microbiology/groups/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 ## Key points - Flea-infested kitten, a papule and a large regional node: cat scratch disease. - Fever, hemolytic anemia and bacilli inside red cells after a stay in an Andean valley: Oroya fever. - Vascular skin nodules: verruga peruana (B. bacilliformis) or bacillary angiomatosis in HIV (B. henselae). - A cause of culture-negative endocarditis. - Colombia: historic Carrión disease focus in Nariño (Guáitara River). ## 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 →](https://durgical.com/en/conditions/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: - [Azithromycin](https://durgical.com/en/pharmacology/azithromycin/) - [Ciprofloxacin](https://durgical.com/en/pharmacology/ciprofloxacin/) - [Ceftriaxone](https://durgical.com/en/pharmacology/ceftriaxone/) - [Doxycycline](https://durgical.com/en/pharmacology/doxycycline/) - [Rifampicin](https://durgical.com/en/pharmacology/rifampicin/) ## 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 ## In Colombia Carrión disease was described in Colombia in 1939 in the Guáitara River valley, Nariño, as a focus identical to Peru's Andean wart. The potential vector in the country is Lutzomyia columbiana, found in Nariño, Cauca, Valle del Cauca and other regions. ## Memory aid "Bartonella takes three rides": the scratching cat, the biting Andean sand fly and the louse that travels in clothing. ## 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)](https://durgical.app/estudiar/?add=/en/microbiology/bartonella/) ## Related - [Brucella](https://durgical.com/en/microbiology/brucella/) ## Related conditions - [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. [← Back to the group: Other Gram-negative rods](https://durgical.com/en/microbiology/groups/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](https://www.cdc.gov/bartonella/about/index.html) (CDC, 2026); [Clinical Overview of Bartonella bacilliformis](https://www.cdc.gov/bartonella/hcp/clinical-overview/bartonella-bacilliformis.html) (CDC, 2026); [Oroya Fever and Verruga Peruana](https://www.msdmanuals.com/professional/infectious-diseases/gram-negative-bacilli/oroya-fever-and-verruga-peruana) (MSD Manual Professional Edition, 2026); [Oroya Fever, Verruga Peruana, and Other Bartonelloses Incidence Rates in Colombia (2009-2013)](https://pmc.ncbi.nlm.nih.gov/articles/PMC6318093/) (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. --- Source: https://durgical.com/en/microbiology/bartonella/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/bartonella/