Bartonella

Taxobox
color = lightgrey
name = "Bartonella"
regnum = Bacteria
phylum = Proteobacteria
classis = Alpha Proteobacteria
ordo = Rhizobiales
familia = Bartonellaceae
genus = "Bartonella"
genus_authority = Strong et al., 1915
subdivision_ranks = Species
subdivision ="B. alsatica"
"B. bacilliformis"
"B. birtlesii"
"B. bovis"
"B. capreoli"
"B. clarridgeiae"
"B. doshiae"
"B. elizabethae"
"B. grahamii"
"B. henselae"
"B. koehlerae"
"B.muris"
"B. peromysci"
"B. quintana"
"B. rochalimae"
"B. schoenbuchii"
"B. talpae"
"B. taylorii"
"B. tribocorum"
"B. vinsonii spp. arupensis"
"B. vinsonii spp. berkhoffii"
"B. vinsonii spp. vinsonii"
"B. washoensis"
"etc."

"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.cite book | author = Walker DH | title = Rickettsiae. "In:" Barron's Medical Microbiology "(Barron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.2138| isbn = 0-9631172-1-1 ] "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.cite journal | author = Chomel BB, Boulouis HJ | title = [Zoonotic diseases caused by bacteria of the genus Bartonella genus: new reservoirs ? New vectors?] | language = French | journal = Bull. Acad. Natl. Med. | volume = 189 | issue = 3 | pages = 465–77; discussion 477–80 | year = 2005 | pmid = 16149211 | doi = ] In June 2007, a new species under the genus, called "Bartonella rochalimae", was discovered.cite journal | author = Eremeeva ME, Gerns HL, Lydy SL, "et al" | title = Bacteremia, Fever, and Splenomegaly Caused by a Newly Recognized "Bartonella" Species | journal = N Engl J Med | year = 2007 | volume = 356 | pages = 2381–7 | url = | doi = 10.1056/NEJMoa065987 | pmid = 17554119] This is the sixth species known to infect humans, and the ninth species and subspecies, overall, known to infect humans.

History

"Bartonella" species have been infecting humans for thousands of years, as demonstrated by "Bartonella quintana" DNA in a 4000 year old tooth.cite journal | author = Drancourt M, Tran-Hung L, Courtin J, Lumley H, Raoult D | title = Bartonella quintana in a 4000-year-old human tooth | journal = J. Infect. Dis. | volume = 191 | issue = 4 | pages = 607–11 | year = 2005 | pmid = 15655785 | doi = 10.1086/427041] The genus is named after Alberto Leonardo Barton Thompson, a Peruvian scientist born in Argentina.

"Bartonella" was detected in ticks in 1999.cite journal | author = Schouls LM, Van De Pol I, Rijpkema SG, Schot CS | title = Detection and identification of Ehrlichia, Borrelia burgdorferi sensu lato, and Bartonella species in Dutch Ixodes ricinus ticks | journal = J. Clin. Microbiol. | volume = 37 | issue = 7 | pages = 2215–22 | year = 1999 | pmid = 10364588 | doi = ] Several species are a human pathogens carried on rats. [ [http://www.ratbehavior.org/WildRatDisease.htm RatBehavior.org] ]

In 2001 doctors treating Lyme disease first reported that their patients were co-infected with "Bartonella".cite journal | author = Eskow E, Rao RV, Mordechai E | title = Concurrent infection of the central nervous system by Borrelia burgdorferi and Bartonella henselae: evidence for a novel tick-borne disease complex | journal = Arch. Neurol. | volume = 58 | issue = 9 | pages = 1357–63 | year = 2001 | pmid = 11559306 | doi =10.1001/archneur.58.9.1357 ] Multiple reports of this finding seem to indicate that "Bartonella" is not only a tick borne but a tick-transmitted pathogen;cite journal | author = Stricker RB, Brewer JH, Burrascano JJ, "et al" | title = Possible role of tick-borne infection in "cat-scratch disease": comment on the article by Giladi et al | journal = Arthritis Rheum. | volume = 54 | issue = 7 | pages = 2347–8 | year = 2006 | pmid = 16802385 | doi = 10.1002/art.21925] .

Infection cycle

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, a part of the "Bartonella" in the endothelial cells are released in the blood stream where they infect erythrocytes. The bacteria then invade and replicate within a phagosomal membrane inside the erythrocytes. Inside the erythrocytes, bacteria multiply until they reach a critical population density. At this point, the "Bartonella" has simply to wait until it is taken with the erythrocytes by a blood-sucking arthropod.

Pathophysiology

"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.cite journal | author = Rolain JM, Brouqui P, Koehler JE, Maguina C, Dolan MJ, Raoult D | title = Recommendations for treatment of human infections caused by Bartonella species | journal = Antimicrob. Agents Chemother. | volume = 48 | issue = 6 | pages = 1921–33 | year = 2004 | pmid = 15155180 | doi = 10.1128/AAC.48.6.1921-1933.2004]

Treatment

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.

Epidemiology

Whether because rodent associated, IV transmitted or because tick borne disease is higher risk for the homeless, 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, [cite journal | author = Smith HM, Reporter R, Rood MP, "et al" | title = Prevalence study of antibody to ratborne pathogens and other agents among patients using a free clinic in downtown Los Angeles | journal = J. Infect. Dis. | volume = 186 | issue = 11 | pages = 1673–6 | year = 2002 | pmid = 12447746 | doi =10.1086/345377 ] to 33% in Baltimore, Maryland, [cite journal | author = Comer JA, Flynn C, Regnery RL, Vlahov D, Childs JE | title = Antibodies to Bartonella species in inner-city intravenous drug users in Baltimore, Md | journal = Arch. Intern. Med. | volume = 156 | issue = 21 | pages = 2491–5 | year = 1996 | pmid = 8944742 | doi =10.1001/archinte.156.21.2491 ] 46% in New York, [cite journal | author = Comer JA, Diaz T, Vlahov D, Monterroso E, Childs JE | title = Evidence of rodent-associated Bartonella and Rickettsia infections among intravenous drug users from Central and East Harlem, New York City | journal = Am. J. Trop. Med. Hyg. | volume = 65 | issue = 6 | pages = 855–60 | year = 2001 | pmid = 11791987 | doi = ] and in Sweden 39%. [cite journal | author = McGill S, Hjelm E, Rajs J, Lindquist O, Friman G | title = Bartonella spp. antibodies in forensic samples from Swedish heroin addicts | journal = Ann. N. Y. Acad. Sci. | volume = 990 | issue = | pages = 409–13 | year = 2003 | pmid = 12860665 | doi = ]

ee also

Cat scratch fever

References