Bartonella bacilliformis
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''Bartonella bacilliformis'' 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 ...
,
Gram negative The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to th ...
aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cel ...
, pleomorphic, flagellated, motile, coccobacillary, 2–3 μm long, 0.2–0.5 μm wide, and a facultative intracellular bacterium.


History

The bacterium was discovered by
Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...
vian microbiologist
Alberto Barton Alberto Barton (1870-1950) was an Argentine-born Peruvian microbiologist who discovered the etiologic agent of Carrion´s disease or Oroya fever. The bacteria was named: '' Bartonella bacilliformis'', in his honor. It is the type species of t ...
in 1905, but it was not published until 1909. Barton originally identified them as endoglobular structures, which actually were the bacteria living inside
red blood cell 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 ...
s. Until 1993, the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Bartonella'' contained only one species; there are now more than 23 identified species, all of them within family Bartonellaceae.


Epidemiology

''Bartonella bacilliformis'' is found only in
Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...
,
Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...
, and Colombia and some areas of south Florida . It is
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
in some areas of
Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...
, with outbreaks of the disease occurring in new epidemic areas. The bacterium is transmitted by
sandflies Sandfly (or sand fly) is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhe ...
of the genus ''
Lutzomyia ''Lutzomyia'' is a genus of phlebotomine sand flies consisting of nearly 400 species, at least 33 of which have medical importance as vectors of human disease. Species of the genus ''Lutzomyia'' are found only in the New World, distributed in ...
''.


Microbiology

For its isolation, special cultures are required, containing complemental soy agar,
protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...
s, peptones, some essential
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
s, and blood. The optimum growing temperature is 19–29 °C. Colonies grow in Columbia blood agar supplemented with 10% defibrinated bovine blood incubated at 19–25 °C for 2 weeks.


Pathophysiology

As the
sandflies Sandfly (or sand fly) is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhe ...
bite, the bacteria are inoculated into the capillaries, where in a variable period of time (around 21 days) it invades the red blood cells producing severe intravascular hemolytic anemia (acute phase of Carrion's disease). This phase is a potentially life-threatening infection, and it is associated with high
fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...
, anemia, and transient
immunosuppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reacti ...
. The acute phase typically lasts two to four weeks. Peripheral blood smears show anisomacrocytosis with many coccobacilli adhered to red blood cells.
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 ...
is also seen and can be severe. Neurological involvement is sometimes seen (neurobartonellosis) and the prognosis in this case is poor. The most feared complications are super-infections, mainly by
enterobacteria Enterobacteriaceae is a large family of Gram-negative bacteria 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 ...
such as '' Salmonella'', or parasites such as ''
Toxoplasma gondii ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...
'' and ''
Pneumocystis The Pneumocystidomycetes are a class of ascomycete fungi. It includes the single order Pneumocystidales, which contains the single monotypic family Pneumocystidaceae, which in turn contains the genus Genus ( plural genera ) is a taxonomic r ...
''. When the bacterium invades endothelial cells, it produces the chronic manifestation of the disease known as ''verruga peruana''. This phase consists of a
benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...
skin eruption with raised, reddish-purple nodules ( angiomatous tumours). Visualization of the bacteria is possible using
silver stain In pathology, silver staining is the use of silver to selectively alter the appearance of a target in microscopy of histological sections; in temperature gradient gel electrophoresis; and in polyacrylamide gels. In traditional stained glass, silv ...
(the Warthin–Starry method) on biopsies.


Disease

''Bartonella bacilliformis'' is the etiologic agent of Carrion's disease or Oroya fever (acute phase of infection), and ''
verruga peruana Carrion's disease is an infectious disease produced by '' Bartonella bacilliformis'' infection. It is named after Daniel Alcides Carrión. Signs and symptoms The clinical symptoms of bartonellosis are pleomorphic and some patients from endemi ...
'' or Peruvian wart (chronic phase of infection). The acute phase of the disease is a life-threatening disease characterized by massive invasion of ''Bartonella'' to human red blood cells and consequently acute
hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing ( lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...
and fever. If the infection is not treated, the case fatality rate is 40 to 85% Patients in this phase of the infection can be complicated by overwhelming infections, primarily by enterobacteria (''Salmonella'' spp) and parasites (''Toxoplasma gondii'', ''Pneumocystis jirovecii''). The chronic phase is characterized by benign eruptive lesions that are
pruritic Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasan ...
and bleeding, and other symptoms like malaise and osteoarticular pain. Bartonella can be isolated from blood cultures and secretion of the lesions in people from endemic areas.


Treatment

Before the antibiotic era, the only treatment for the acute phase was blood transfusion, but the effectiveness of this treatment was poor and the mortality rate was high. Later, with the discovering of new antibiotics, penicillin, chloramphenicol,
tetracycline Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis. Common side effects in ...
, and erythromycin have been used successfully. However, because of the risk of overwhelming infections by enterobacteria,
quinolones Quinolone may refer to: * 2-Quinolone * 4-Quinolone 4-Quinolone is an organic compound derived from quinoline. It and 2-quinolone are the two most important parent (meaning simplified) quinolones. 4-Quinolone exists in equilibrium with a mino ...
are preferred. Therapeutic failures and persistent bacteremia have been reported with chloramphenicol, and successful treatment with this drug does not appear to eliminate the patient's risk for development of the eruptive phase. So, the drug of choice is
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 inf ...
. In the chronic phase, the treatment used traditionally has been
streptomycin Streptomycin is an antibiotic medication used to treat a number of bacterial infections, including tuberculosis, ''Mycobacterium avium'' complex, endocarditis, brucellosis, ''Burkholderia'' infection, plague, tularemia, and rat bite fever. F ...
for 10 days. Since 1975,
rifampin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. It is almost always used tog ...
has become the drug of choice for ''verruga peruana''. However, failures of rifampin treatment have also been reported and resistance can develop. Recently
macrolide The Macrolides are a class of natural products that consist of a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. The lactone rings are usually 14-, 15-, or 16-membered. Ma ...
s have been used with similar effectiveness.


References


External links


Human Bartonellosis caused by ''Bartonella bacilliformis''

''Bartonella bacilliformis''
in the NCBI Taxonomy Browser {{DEFAULTSORT:Bartonella Bacilliformis Bartonellaceae Bacteria described in 1913