''Bartonella quintana'', originally known as ''Rochalimaea quintana'', and "''Rickettsia quintana''", is a

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were amon ...

transmitted by the human body louse that causes

trench fever Trench fever (also known as "five-day fever", "quintan fever" ( la, febris quintana), and "urban trench fever") is a moderately serious disease transmitted by body lice. It infected armies in Flanders, France, Poland, Galicia, Italy, Salonika, Ma ...

. This bacterial species caused outbreaks of trench fever affecting 1 million soldiers in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

Genome

''B. quintana'' had an estimated

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

size of 1,700 to 2,174 kb., but the first genome sequence (of strain RM-11) contains a single circular chromosome of 1,587,646 base pairs.

Background and characteristics

''B. quintana'' is a

fastidious A fastidious organism is any organism that has complex or particular nutritional requirements. In other words, a fastidious organism will only grow when specific nutrients are included in its medium. The more restrictive term fastidious microorga ...

, aerobic,

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

(-), pole rod-shaped (

bacillus ''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum '' Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacill ...

) bacterium. The infection caused by this microorganism, trench fever, was first documented in soldiers during World War I, but has now been seen Europe, Asia, and North Africa. Its primary vector is known to be ''

Pediculus humanus ''Pediculus humanus'' is a species of louse that infects humans. It comprises two subspecies: *''Pediculus humanus humanus'' Linnaeus, 1758 – body louse *''Pediculus humanus capitis'' De Geer, 1767 – head louse The head louse (''Pedicu ...

'' variety ''corporis'', also known as the human body louse. It was first known to be isolated in axenic culture by J.W. Vinson in 1960, from a patient in Mexico City. He then followed

Koch's postulates Koch's postulates ( )"Koch"
''

animal vectors, humans (and some other primates) are the only known animal reservoir hosts for this bacterium ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

''. It infects

endothelial cells The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...

and can infect

erythrocytes Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

by binding and entering with a large vacuole. Once inside, they begin to proliferate and cause nuclear atypia (intraerythrocytic ''B.quintana'' colonization). This leads to apoptosis being suppressed, proinflammatory cytokines are released, and vascular proliferation increases. All of these processes result in patients possessing systemic symptoms (chills, fever, diaphoresis), bacteremia, and lymphatic enlargement. A major role in ''B. quintana'' infection is its lipopolysaccharide covering which is an antagonist of the toll-like receptor 4. The reason this infection might persist is because this organism also results in monocytes overproducing interleukin-10 (IL-10), thus weakening the immune response. ''B. quintana'' also induces lesions seen in

bacillary angiomatosis Bacillary angiomatosis (BA) is a form of angiomatosis associated with bacteria of the genus '' Bartonella''. Symptoms Cutaneous BA is characterised by the presence of lesions on or under the skin. Appearing in numbers from one to hundreds, these l ...

that protrude into vascular lumina, often occluding blood flow. The enhanced growth of these cells is believed to be due to the secretion of

angiogenic Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splittin ...

factors, thus inducing

neovascularization Neovascularization is the natural formation of new blood vessels ('' neo-'' + '' vascular'' + '' -ization''), usually in the form of functional microvascular networks, capable of perfusion by red blood cells, that form to serve as collateral circu ...

. Release of an

icosahedral In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes and . The plural can be either "icosahedra" () or "icosahedrons". There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrica ...

particle, 40 nm in length, has been detected in cultures of ''B. quintana's'' close relative, ''B. henselae''. This particle contains a 14-kb linear DNA segment, but its function in ''Bartonella'' pathophysiology is still unknown. In trench fever or ''B. quintana''-induced endocarditis patients, bacillary angiomatosis lesions are also seen. Notably, endocarditis is a new manifestation of the infection, not seen in World War I troops.

Ecology and epidemiology

''B. quintana'' infection has subsequently been seen in every continent except Antarctica. Local infections have been associated with risk factors such as poverty, alcoholism, and homelessness. Serological evidence of ''B. quintana'' infection showed, of hospitalized homeless patients, 16% were infected, as opposed to 1.8% of nonhospitalized homeless persons, and 0% of blood donors at large. Lice have been demonstrated, as of recently, to be the key component in transmitting ''B. quintana''. This has been attributed to living in unsanitary conditions and crowded areas, where the risk of coming into contact with other individuals carrying ''B. quintana'' and

ectoparasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

(body lice) is increased. Also noteworthy, the increasing migration worldwide may also play a role in spreading trench fever, from areas where it is endemic to susceptible populations in urban areas. Recent concern is the possibility of the emergence of new strains of ''B. quintana'' through

horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). H ...

, which could result in the acquisition of other virulence factors.

Clinical manifestations

The clinical manifestations of ''B. quintana'' infection are highly variable. The

incubation period Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the in ...

is now known to be 5–20 days; it was originally thought to be 3–38 days. The infection can start as an acute onset of a febrile episode, relapsing febrile episodes, or as a persistent typhoidal illness; commonly seen are

maculopapular rash A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. It may only appear red in lighter-skinned people. The term "maculopapular" is a compound: '' macules'' are small, flat ...

es,

conjunctivitis Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...

, headache, and myalgias, with

splenomegaly Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of ''hypersplenism'' which include: some reduction in number of circulatin ...

being less common. Most patients present with pain in the lower legs (shins), sore muscles of the legs and back, and hyperaesthesia of the shins. Rarely is ''B. quintana'' infection fatal, unless

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...

develops and goes untreated. Weight loss, and

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients a ...

are sometimes also seen. Recovery can take up to a month.

Diagnosis and treatment

To have a definite diagnosis of infection with ''B. quintana'' requires either serological cultures or nucleic acid amplification techniques. To differentiate between different species, immunofluorescence assays that use mouse antisera are used, as well as DNA hybridization and restriction fragment length polymorphisms, or

citrate synthase The enzyme citrate synthase E.C. 2.3.3.1 (previously 4.1.3.7)] exists in nearly all living cells and stands as a pace-making enzyme in the first step of the citric acid cycle (or Krebs cycle). Citrate synthase is localized within eukaryotic cel ...

gene sequencing. Treatment usually consists of a 4- to 6-week course of doxycycline, erythromycin, or

azithromycin Azithromycin, sold under the brand names Zithromax (in oral form) and Azasite (as an eye drop), is an antibiotic medication used for the treatment of a number of bacterial infections. This includes middle ear infections, strep throat, pneumo ...

References

External links

*
Type strain of ''Bartonella quintana'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q148561 Bartonellaceae Bacteria described in 1993