Bartonella
From MicrobeWiki, the student-edited microbiology resource
A Microbial Biorealm page on the genus Bartonella
Contents |
Classification
Higher order taxa
Domain: Bacteria; Phylum: Proteobacteria; Class: Alpha Proteobacteria; Order: Rhizobiales; Family: Bartonellacea; Genus: Bartonella [Others may be used. Use NCBI link to find]
Species
|
NCBI: Taxonomy |
Genus species: 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
Description and significance
Bartonella Bacilliformis first captured in 1909, is a proteobacterium that can be contracted by a Sand Fly located in South America. This microorganism is deadly and harms the red blood cells by entering them and deforming the surface. (11) The deformation is caused by developing invaginations and pits. B. bacilliformis happens to be gram negative and reveals itself under a microscope as a purple rod or cocci. B. bacilliformis has certain physical characteristics such as, a thin cell wall, flagella, and actually contains a double membrane. Its method of multiplicity is through dividing via binary fission. A suitable temperature just so happens to be at 28 degrees C with a pH level of 7.8. This disease can be treated by Penicillin, Chloramphenicol, and Streptomycin. (10)
Genome structure
Bartonella contains 14 species and the genome is relatively similar for all sequenced species. For example, the complete genomes for Bartonella quintana, Bartonella bacilliformis, and Bartonella henselae have been sequenced and genome comparison shows a high degree of similarity (6). The genome of Bartonella varies between one million and two million base pairs depending on species. It is a circular chromosome and codes for approximately 1300 protein genes and 50 RNA genes.
Cell structure and metabolism
B. bacilliformis is a gram-negative aerobic rod shaped bacterium that is non-spore forming and is highly motile. A striking characteristic feature is its spirally curved flagella, present at one end of the body and may be 2-4 in number. On average, B. bacilliformis is 2-3 μm large and 0.2-0.5 μm wide. It thrives in blood cultures or any environment containing blood elements and makes its appearance within 24 hours of infection. This bacterium is unable to grow on any liquid medium or any medium that lacks blood elements. In humans, they inhabit places such as the endothelial cells of blood vessels and erythrocytes. The bacterium is comprised of thin walls and a double membrane and is able to divide by binary fission (4).
B. bacilliformis is pleomorphic, meaning that during its life cycle it takes on two or more structural forms. This bacterium can live both inside and outside the cell. The optimum temperature it grows best at is 25°C however; the bacterium has been seen to grow in the range of 19-29°C (4).
Ecology
B.bacilliformis, the causative agent of bacterial infection Bartonellosis, or Carrion’s disease, remains endemic in region of Colombia, Ecuador and river valleys of Andes Mountains of Peru, especially in Rimac and Santa Eulalia river valleys. Recent outbreaks discovered near Cuzco, Peru. Based in the last reports of new cases, actually the jungle is the most important area of transmission of Bartonellosis. In addition, there is evidence that “el Nino” weather phenomena may influence the spread of Bartonellosis (3). This bacterium is a facultative intracellular parasite, which uses a sand fly (sp. Lutzomyia verrucarrum) as its main vector for distribution. B.bacilliformis enters the bloodstream through the bite of a sand fly (1)(2), which mainly found in the western Andes, at elevations of 700 to 2500 meters. These regions are dominated by warm temperatures, which are favorable for survival of this sand fly. B.bacilliformis has shown to survive in tap water at room temperature for up to seven days, being susceptible to disinfectants, resistant to drugs such as nalidixic acid, tetracycline, and vancomycin, and in vitro to penicillin and ampicillin.
Epidemiology
Human infections due to Bartonella species are considered emerging diseases. Bartonella bacilliformis, Bartonella henselae, and Bartonella quintana are long recognized and the most commonly found species of Bartonella known to cause Carrion’s disease, cat scratch fever, and trench fever respectively. As previously mentioned, B bacilliformis is found in Peru, Ecuador, and Columbia. Its transmission is secluded to the Andes Mountains at elevations of 1000-3000 meters. Any outbreaks of B.bacillifromis infections seen anywhere other than this specific location are found in travelers. Both B. henselae and B. quintana are found worldwide. B. henselae is responsible for approximately 22,000 infections per year occurring mostly in warm, humid climates during autumn and winter. B.quintana is found increasingly among homeless populations in the U.S. and Europe (7).
Pathology
Transmission
Bartonella bacillifromis, Bartonella henselae, and Bartonella quintana are considered important causes of human diseases. Bartonella bacilliformis, Bartonella henselae, and Bartonella quintana are vector borne pathogens, which use mammalian reservoirs. No animal reservoirs have been indentified for Bartonella bacilliformis or Bartonella quintana however, an animal reservoir, cats, has been identified for Bartonella henselae. B. henselae is transferred to humans from cats by a cat scratch, B. quintana is transferred human to human through body lice and B. bacilliformis is transferred human to human through the bite of an infected sand fly. All three bacterium enter the host’s bloodstream and invades red blood cells. For example, B. bacilliformis is known to replicate in vacuoles upon entry into the host and then make endothelial cell stimulation factors, which cause proliferation of endothelial cells and blood vessels (7)
Diseases and Symptoms
Carrion’s disease, caused by Bartonella bacilliformis, is an infection, which has two distinct phases. The acute phase, Oroya fever, is characterized by a sudden onset of fever and severe anemia while the chronic illness, verruga peruanan, is characterized by red/purple lesions found on the skin. Oroya fever has a high fatality rate of about 40%. (8).
Cat scratch fever, caused by Bartonella henselae, occurs within cats and found in humans who have been bit or scratched by an infected cat. Approximately 40% of cats carry B. henselae and do not show any sign of illness. However, in humans, a mild infection appears at site of injury and lymph nodes become swollen. Infected people may also experience fever, headache, fatigue and poor appetite (9).
Trench fever, caused by Bartonella quintana, is a blood borne infection characterized by sudden onset of headache, meningitis, pain in the legs, and relapsing fever. Little is known about the pathophysiology of trench fever. Recovery takes a month or more and lethal cases are rare (7).
Current Research
The bacteria B. henselae is the cause of the cat-scratch disease and is associated with ailments such as ocular infections and endocarditis. However, scientists have possibly found a new vector for transmitting the disease. Previously, fleas were the vectors that transmitted the disease to cats. Now, a tick species known as Ixodes Ricinus, the most abundant tick found in Western Europe that bites humans, has had traces of bacterial DNA within its genes. The bacteria are ingested while ticks feed on animal skin and remains in the tick even after molting. Scientists have demonstrated this idea by having artificial skin that B. henselae could be transmitted by the saliva of the tick. More investigation is needed in order to classify B. henselae as a tick-borne pathogen. A possible theory of transfer from cats to humans is that the cats are infested with ticks that then pass on the ticks to their human owners (5).
References
1. Kreier, J. P. & Ristic, M. (1981). The biology of hemotrophic bacteria. Annu Rev Microbiol 35, 325±338.
2. Hertig, M. (1942). Phlebotomus and Carrion's disease. Am J Trop Med 22, 1±76.
3. Zhou J, Laughlin L, Andre R, et al. El Nino and the spread of bartonellosis epidemics in Peru. EOS Trans Am Geophysical Union 2002;83:157, 160-1
4. Muller, Henry R., Noguchi, Hideyo, Tilden, Evelyn B., and Tyler, Joseph R. “Etiology of Oroya Fever.Effect of Immune Serum on the Course of Bartonella Bacilliformis Infection in Macacus Rhesus.” (June 1929).
5. Cotté, Violaine, et al. "Transmission of Bartonella henselae by Ixodes ricinus." Emerging Infectious Diseases 14.7 (July 2008): 1074-1080. Academic Search Premier. EBSCO.1 Dec. 2008.
6. Alsmark, C. (n.d.). The louse-borne human pathogen Bartonella quintana is a genomic derivative of the zoonotic agent Bartonella henselae. In KEGG Genome. Retrieved November 23, 2008
7.Liang, Z., La Scola, B., Lepidi, H., & Raoult, D. (2001). Production of Bartonella Genus-Specific Monoclonal Antibodies. Clinical Diagnostic Lab Immunology, 8(4), 847-849. Retrieved from Pubmed database.
8. Panicker, V. (2004). Bartonella bacilliformis. In Microbe of the Week 2004. Retrieved November 23, 2008
9. Bartonella henselae Infection. (n.d.). National Center for Infectious Disease. Retrieved November 23, 2008
10. Yanji Xu and Yan Chai, (2002) Bartonella bacilliformis: Molecular Mechanisms of Invasion, Einstein Quart. J. Biol. Med. (2002) 19:56-58.Retrieved November 22,2008
11.(05 Mar 2000) Retrieved November 22,2008
Edited by student of Dr. Kirk Bartholomew
