Strong et al., 1915
Bartonella (formerly known as Rochalimaea) is a genus of Gram-negative bacteria. Facultative intracellular parasites, Bartonella species can infect healthy people but are considered especially important as opportunistic pathogens. Bartonella are transmitted by insect vectors such as ticks, fleas, sand flies, and mosquitoes. At least eight Bartonella species or subspecies are known to infect humans.
Bartonella species have been infecting humans for thousands of years, as demonstrated by Bartonella quintana DNA in a 4000-year-old tooth. The genus is named for Alberto Leonardo Barton Thompson (1871 - October 26, 1950), a Peruvian scientist born in Argentina.
The currently accepted model explaining the infection cycle holds that the transmitting vectors are blood-sucking arthropods and the reservoir hosts are mammals. Immediately after infection, the bacteria colonize a primary niche, the endothelial cells. Every five days, some of the Bartonella in the endothelial cells are released into the blood stream, where they infect erythrocytes. The bacteria then invade a phagosomal membrane inside the erythrocytes, where they multiply until they reach a critical population density. At this point, the Bartonella simply wait until they are taken up with the erythrocytes by a blood-sucking arthropod.
Though some studies have found "no definitive evidence of transmission by a tick to a vertebrate host,"   Bartonella species are well-known to be transmissible to both animals and humans through various other vectors such as fleas, lice, and sand flies. Recent studies have shown a strong correlation between tick exposure and bartonellosis,  including human bartonellosis. Bartonella are the bacteria associated with cat-scratch disease, but a study in 2010 concluded, "Clinicians should be aware that . . . a history of an animal scratch or bite is not necessary for disease transmission."  All current Bartonella species identified in canines are human pathogens.
Bartonella infections are remarkable in the wide range of symptoms an infection can produce: the time course (acute or chronic) as well as the underlying pathology are highly variable.
|Bartonella pathophysiology in humans|
|Species||Human reservoir or
|B. bacilliformis||Reservoir||Causes Carrion's disease (Oroya fever, Verruga peruana)||Peru, Ecuador, and Colombia|
|B. quintana||Reservoir||Causes Trench fever, Bacillary angiomatosis, and endocarditis||Worldwide|
|B. clarridgeiae||Incidental||Domestic cat||Cat-scratch Disease|
|B. grahamii||Incidental||Mouse||Endocarditis and Neuroretinitis|
|B. henselae||Incidental||Domestic cat||Cat-scratch Disease, Bacillary angiomatosis, Peliosis hepatis, Endocarditis, Bacteremia with fever and Neuroretinitis||Worldwide|
|B. koehlerae||Incidental||Domestic cat|
|B. vinsonii||Incidental||Mouse, Dog, Domestic Cat|
|B. rochalimae||Incidental||Unknown||Carrion's disease-like symptoms|
Treatment is dependent on which strain of Bartonella is found in a given patient. While Bartonella species are susceptible to a number of standard antibiotics in vitro — macrolides and tetracycline, for example — the efficacy of antibiotic treatment in immunocompetent individuals is uncertain. Immunocompromised patients should be treated with antibiotics because they are particularly susceptible to systemic disease and bacteremia. Drugs of particular effectiveness include trimethoprim-sulfamethoxazole, gentamicin, ciprofloxacin, and rifampin; B. henselae is generally resistant to penicillin, amoxicillin, and nafcillin.
Homeless IV drug users are at high risk for Bartonella infections, particularly B. elizabethae. B. elizabethae seropositivity rates in this population range from 12.5% in Los Angeles, to 33% in Baltimore, Maryland, 46% in New York, and in Sweden 39%.
- Walker DH (1996). Rickettsiae. In: Barron's Medical Microbiology (Barron S et al., eds.) (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1.
- Chomel BB, Boulouis HJ (2005). "[Zoonotic diseases caused by bacteria of the genus Bartonella genus: new reservoirs ? New vectors?]". Bull. Acad. Natl. Med. (in French) 189 (3): 465–77; discussion 477–80. PMID 16149211.
- Drancourt M, Tran-Hung L, Courtin J, Lumley H, Raoult D (2005). "Bartonella quintana in a 4000-year-old human tooth". J. Infect. Dis. 191 (4): 607–11. doi:10.1086/427041. PMID 15655785.
- Angelakis E, Billeter SA, Breitschwerdt EB, Chomel BB, Raoult D (March 2010). "Potential for tick-borne bartonellosis". Emerg Infect Dis 16 (3): 385–91. doi:10.3201/eid1603.091685. PMID 20202411.
- Telford SR III, Wormser GP (March 2010). "Bartonella spp. transmission by ticks not established". Emerg Infect Dis 16 (3): 379–84. doi:10.3201/eid1603.090443. PMID 20202410.
- Billeter SA, Levy MG, Chomel BB, Breitschwerdt EB (Mar 2008). "Vector transmission of Bartonella species with emphasis on the potential for tick transmission". Med Vet Entomol 22 (1): 1–15. doi:10.1111/j.1365-2915.2008.00713.x. PMID 18380649.
- Eskow E, Rao RV, Mordechai E (Sep 2001). "Concurrent infection of the central nervous system by Borrelia burgdorferi and Bartonella henselae: evidence for a novel tick-borne disease complex". Arch Neurol 58 (9): 1357–63. doi:10.1001/archneur.58.9.1357. PMID 11559306.
- Mosbacher M, Elliott SP, Shehab Z, Pinnas JL, Klotz JH, Klotz SA (Sep-Oct 2010). "Cat scratch disease and arthropod vectors: more to it than a scratch?". J Am Board Fam Med 23 (5): 685–6. doi:10.3122/jabfm.2010.05.100025. PMID 20823366.
- Chomel BB, Boulouis HJ, Maruyama S, Breitschwerdt EB (Mar 2006). "Bartonella spp. in pets and effect on human health". Emerg Infect Dis 12 (3): 389–94. doi:10.3201/eid1203.050931. PMID 16704774.
- Rolain JM, Brouqui P, Koehler JE, Maguina C, Dolan MJ, Raoult D (2004). "Recommendations for treatment of human infections caused by Bartonella species". Antimicrob. Agents Chemother. 48 (6): 1921–33. doi:10.1128/AAC.48.6.1921-1933.2004. PMC 415619. PMID 15155180.
- Zeaiter Z, Liang Z, Raoult D (2002). "Genetic classification and differentiation of Bartonella species based on comparison of partial ftsZ gene sequences". J. Clin. Microbiol. 40 (10): 3641–7. doi:10.1128/JCM.40.10.3641-3647.2002. PMC 130884. PMID 12354859.
- Jacomo V, Kelly PJ, Raoult D (2002). "Natural history of Bartonella infections (an exception to [[Koch's postulates|Koch's postulate]])". Clin. Diagn. Lab. Immunol. 9 (1): 8–18. doi:10.1128/CDLI.9.1.8-18.2002. PMC 119901. PMID 11777823. Wikilink embedded in URL title (help)
- Maco V, Maguiña C, Tirado A, Maco V, Vidal JE (2004). "Carrion's disease (Bartonellosis bacilliformis) confirmed by histopathology in the High Forest of Peru". Rev. Inst. Med. Trop. Sao Paulo 46 (3): 171–4. doi:10.1590/S0036-46652004000300010. PMID 15286824.
- Smith HM, Reporter R, Rood MP et al. (2002). "Prevalence study of antibody to ratborne pathogens and other agents among patients using a free clinic in downtown Los Angeles". J. Infect. Dis. 186 (11): 1673–6. doi:10.1086/345377. PMID 12447746.
- Comer JA, Flynn C, Regnery RL, Vlahov D, Childs JE (1996). "Antibodies to Bartonella species in inner-city intravenous drug users in Baltimore, Md". Arch. Intern. Med. 156 (21): 2491–5. doi:10.1001/archinte.156.21.2491. PMID 8944742.
- Comer JA, Diaz T, Vlahov D, Monterroso E, Childs JE (2001). "Evidence of rodent-associated Bartonella and Rickettsia infections among intravenous drug users from Central and East Harlem, New York City". Am. J. Trop. Med. Hyg. 65 (6): 855–60. PMID 11791987.
- McGill S, Hjelm E, Rajs J, Lindquist O, Friman G (2003). "Bartonella spp. antibodies in forensic samples from Swedish heroin addicts". Ann. N. Y. Acad. Sci. 990: 409–13. doi:10.1111/j.1749-6632.2003.tb07402.x. PMID 12860665.
- Bartonella genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID