''Bartonella'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
Gram-negative
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...
bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
. It is the only genus in the family Bartonellaceae.
, ''Bartonella'' species can infect healthy people, but are considered especially important as
opportunistic pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
s.
''Bartonella'' species are transmitted by
vectors such as
flea
Flea, the common name for the order (biology), order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by hematophagy, ingesting the blood of their hosts. Adult f ...
s,
sand flies, and
mosquito
Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...
es. At least eight ''Bartonella'' species or
subspecies
In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
are known to infect humans.
''
Bartonella henselae'' is the organism responsible for
cat scratch disease.
History
''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
Peru
Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
vian scientist.
Infection cycle
Though some studies have found "no definitive evidence of transmission by a tick to a
vertebrate
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain.
The vertebrates make up the subphylum Vertebra ...
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.
''Bartonella'' bacteria are 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.
Pathophysiology
''Bartonella'' infections are remarkable in the wide range of symptoms they can produce. The course of the diseases (acute or chronic) and the underlying pathologies are highly variable.
Treatment
Treatment is dependent on which species or strain of ''Bartonella'' is found in a given patient. While ''Bartonella'' species are susceptible to a number of standard antibiotics ''
in vitro
''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...
''—
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
Gentamicin is an aminoglycoside antibiotic used to treat several types of bacterial infections. This may include bone infections, endocarditis, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis amo ...
,
ciprofloxacin
Ciprofloxacin is a fluoroquinolone antibiotic used to treat a number of bacterial infections. This includes bone and joint infections, intra-abdominal infections, certain types of infectious diarrhea, respiratory tract infections, skin ...
, and
rifampin; ''B. henselae'' is generally resistant to
penicillin
Penicillins (P, PCN or PEN) are a group of beta-lactam antibiotic, β-lactam antibiotics originally obtained from ''Penicillium'' Mold (fungus), moulds, principally ''Penicillium chrysogenum, P. chrysogenum'' and ''Penicillium rubens, P. ru ...
,
amoxicillin, and nafcillin.
Epidemiology
Homeless intravenous 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
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...
, to 33% in
Baltimore, Maryland
Baltimore is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 United States census, 2020 census and estimated at 568,271 in 2024, it is the List of United States ...
, 46% in
New York City
New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...
, and 39% in
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
.
Phylogeny
The currently accepted taxonomy is based on the
List of Prokaryotic names with Standing in Nomenclature
List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...
(LPSN).
The phylogeny is based on whole-genome analysis.
References
External links
''Bartonella''genomes and related information a
PATRIC a Bioinformatics Resource Center funded b
NIAID
{{Authority control
Bartonellaceae
Bacteria genera
Tropical diseases
Pathogenic bacteria