Borrelia
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Borrelia burgdorferi magnified 400 times. |
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| Swellengrebel 1907 |
Borrelia (scientific name Borrelia ) form a genus of relatively large, screw-shaped (also spiral-shaped), gram-negative bacteria from the group of spirochetes . They were named after Amédée Borrel , a bacteriologist from Strasbourg (1867-1936). Most species are pathogenic to humans or animals. The Lyme disease and relapsing fever are examples of infectious diseases caused by Borrelia.
features
Appearance
The cells are helical, have a few (usually five to seven), relatively large coils and, in contrast to other spirochete genera, can be easily displayed with common stains. In the Gram stain they appear gram negative. They are actively mobile and show the special kind of movement typical of spirochetes . The cells appear thin and long with a diameter of 0.2–0.5 µm and a length of 8–30 µm.
Shape change
In vitro studies indicate that Borrelia are able to transform their original elongated shape into a spherical shape under stress . In addition, corresponding studies show that Borrelia can also occur in other form variants, which are summarized under the generic terms L-forms or spheroplasts . Sphaeroplasts have a deficient cell wall or are even without a cell wall. There are also indications that these forms can occur both intracellularly and extracellularly and are able to divide despite their cell wallless form and also to develop back into complete forms.
Growth and metabolism
Borrelia species are heterotrophic . Their metabolism is microaerophilic , so they prefer to grow at an oxygen concentration that is significantly lower than that of normal air. The description and identification of these bacteria is difficult because they cannot be cultivated with the nutrient media commonly used in microbiology . They are sensitive to small amounts of detergents or bile salts , and they also need numerous growth factors such as amino acids , peptones , vitamins and N-acetylglucosamine , a component of the murein layer in the bacterial cell wall . Optimal growth takes place at a pH of 7.6 in the nutrient medium and incubation at 34–37 ° C. Another peculiarity of the genus is that it works completely without iron and instead uses manganese as a cofactor for important enzymes .
Chemotaxonomy
While most prokaryotes have circular chromosomes , Borrelia have linear DNA . The GC content (the proportion of the nucleobases guanine and cytosine ) in the DNA of Borrelia species is low, at 27–30 mol percent . In addition to the bacterial chromosome, many species have several plasmids , 17 plasmids were found in Borrelia burgdorferi , nine to eleven in B. duttonii and five to six in B. recurrentis .
proof
At the beginning of the 20th century, it was extremely difficult to cultivate Borrelia in a nutrient medium. Some successful attempts have been based on the use of the fluid formed in ascites in the abdominal cavity . This medium was later replaced with blood serum obtained from animals . It was not until the 1980s that a nutrient medium was produced with which some species could be propagated in vitro so that they were accessible for further studies. The so-called BSK II medium has a composition that is usual for nutrient media in cell culture . In addition to numerous growth factors, it also contains gelatine and rabbit serum.
The detection of Borrelia in the patient's blood is carried out by means of serological tests in which the structures of the bacterial cells that act as antigens are detected with the aid of antibodies . An enzyme-linked immunosorbent assay (ELISA) is often used to detect flagellin, a protein of the endoflagella , or a Western blot , also known as immunoblot, to detect the surface proteins . Further diagnostic procedures are described in the article Lyme borreliosis .
Occurrence
Reservoir hosts include small rodents such as rats and mice , from which they are then transmitted to very different organisms using vectors such as ticks . Many animals are immune to Borrelia , others such as horses and dogs or humans are not immune.
Systematics
The genus Borrelia belongs to the family of the Spirochaetaceae in the order of the Spirochaetales . The type species is Borrelia anserina . The genus was first described in 1907 by Nicolaas Hendrik Swellengrebel . Because of the difficult cultivation in culture media, no type strain is stored in a collection of microorganisms for many Borrelia species . Although this is a rule of the Bacteriological Code , in the 1980 Approved Lists of Bacterial Names based on the newly organized code , the species described up to that point were recognized. There is always the remark that no culture is available.
This is associated with consequences for the system, since a type strain must be described and stored for further investigations in order to be able to carry out comparisons with existing species when a new species is discovered. In some species (e.g. duttonii , the causative agent of Central African relapsing fever), the type strain was subsequently cultivated. For species first described after 1980, the rules of the bacteriological code must be observed. If this is not the case, they are not recognized as a separate species, but are given the status of Candidatus , which is the case with " Candidatus Borrelia texasensis". Since the 1990s, phylogenetic examinations have been increasingly carried out to investigate the relationships. The results of these investigations show that the group known as Borrelia burgdorferi sensu lato ( Latin sensu lato , "in the broader sense") consists of closely related species. They were previously partially (as genome group English genomic group ) or genospecies ( English genospecies called).
Internal system
New species are regularly described within the genus. By 2014 39 species were known, by 2020 the number has increased to 43 species:
- Borrelia afzelii Canica et al. 1994 (formerly known as Borrelia genome group VS461)
- Borrelia americana Rudenko et al. 2010
- Borrelia anserina ( Sakharoff 1891) Bergey et al. 1925
- Borrelia baltazardii corrig. (ex Karimi et al. 1979) Karimi et al. 1983
- Borrelia bavariensis Margos et al. 2013
- Borrelia bissettiae Margos et al. 2016
- Borrelia brasiliensis Davis et al. 1952
- Borrelia burgdorferi Johnson et al. 1984 emend. Baranton et al. 1992
- Borrelia californiensis Margos et al. 2016
- Borrelia carolinensis Rudenko et al. 2011
- Borrelia caucasica ( Kandelaki 1945) Davis 1957
- Borrelia coriaceae Johnson et al. 1987
- Borrelia crocidurae ( Leger 1917) Davis 1957
- Borrelia dugesii ( Mazzotti 1949) Davis 1957
- Borrelia duttonii ( Novy & Knapp 1906) Bergey et al. 1925
- Borrelia garinii Baranton et al. 1992
- Borrelia graingeri ( Heisch 1953) Davis 1957
- Borrelia harveyi ( Garnham 1947) Davis 1948
- Borrelia hermsii ( Davis 1942) stone house 1946
- Borrelia hispanica ( de Buen 1926) stone house 1946
- Borrelia japonica Kawabata et al. 1994 (formerly known as Borrelia genome group F63B)
- Borrelia kurtenbachii Margos et al. 2014
- Borrelia lanei Margos et al. 2017
- Borrelia latyschewii ( Sofiev 1941) Davis 1948
- Borrelia lusitaniae Le Fleche et al. 1997 (formerly known as Borrelia genome group PotiB2)
- Borrelia maritima Margos et al. 2020
- Borrelia mayonii Pritt et al. 2016
- Borrelia mazzottii Davis 1956
- Borrelia miyamotoi Fukunaga et al. 1995
- Borrelia parkeri ( Davis 1942) stone house 1946
- Borrelia persica ( Dschunkowsky 1913) stone house 1946
- Borrelia recurrentis ( Lebert 1874) Bergey et al. 1925
- Borrelia sinica Masuzawa et al. 2001
- Borrelia spielmanii Richter et al. 2006
- Borrelia tanukii Fukunaga et al. 1997
- Borrelia theileri ( Laveran 1903) Bergey et al. 1925
- Borrelia tillae Zumpt & Organ 1961
- Borrelia turcica Güner et al. 2004
- Borrelia turdi corrig. Fukunaga et al. 1997
- Borrelia turicatae ( Brumpt 1933) stone house 1946
- Borrelia valaisiana Wang et al. 1997
- Borrelia venezuelensis ( Brumpt 1921) Brumpt 1922
- Borrelia yangtzensis Margos et al. 2015
Important types of Borrelia
- Borrelia burgdorferi sensu lato (collectively for five bacterial species): This after the Swiss researcher Willy Burgdorfer bacteria named were described in 1982 as the causative agent by ticks (in Germany Ixodes Ricinus mites and ticks , in the USA Ixodes dammini transmitted) Lyme disease named (after the place Lyme in the US state Connecticut ). Due to the tick activity, the infections increase, especially in summer and autumn, the infection of the ticks can vary greatly from region to region (5% to 60%). The main characteristics of the early disease are headache, erythema migrans (wandering redness), neurological and arthritic complaints, and many other symptoms can follow.
- Borrelia recurrentis : These Borrelia are the causative agents of relapsing lice fever . They are transmitted by the clothes louse ( Pediculus humanus ). In earlier times there were real epidemics of the disease, especially in areas with poor hygiene and heavy lice infestation , today it is particularly common in the cooler areas of Africa , South America and Asia . The disease is characterized by strong attacks of fever .
- Borrelia duttoni : These Borrelia are also transmitted by ticks ( leather tick Ornithodorus moubata ) and are the cause of relapsed tick fever . This disease is essentially the same as relapsing lice fever , but its occurrence is limited to the warmer areas of the tropics and subtropics .
- Borrelia anserina : These borrelia are also transmitted by ticks and cause poultry pirochetosis in chickens , turkeys , ducks and geese . They occur mainly in tropical and subtropical regions, but individual cases are known from Central Europe.
- Borrelia theileri : These Borrelia were detected in Australia and South Africa in mild diseases of horses , cattle and sheep .
- Borrelia coriaceae : This Borrelia species was isolated from cattle after abortion . The carrier is the tick Ornithodorus coriacaeus .
In addition, there are other borrelia that are regionally widespread and can trigger diseases similar to relapsing fever.
Medical importance
Various borrelia are important pathogens . The diseases caused include: a. the Lyme disease with neuroborreliosis as a manifestation form, cutaneous lymphoid hyperplasia , the relapsing fever as well as Lyme disease of the dog .
Borrelia species pathogenic to humans
The most common Borrelia species found in Germany / Europe is Borrelia burgdorferi . While the genospecies B. burgdorferi sensu stricto occurs in the USA , there are other species that are dangerous to humans in Europe. These are in particular B. garinii , B. afzelii , B. valaisiana , B. lusitaniae and B. spielmanii . It is still unclear whether other species are also pathogenic to humans.
All European Borrelia genospecies were also found in ticks in Germany . Studies indicate that the individual genospecies could be primarily responsible for the respective disease manifestations. However, any species can basically cause any manifestation of disease. Overlapping of different symptoms as well as combinations of different disease manifestations are possible.
Recent studies indicate that the various genospecies are obviously differently complement-sensitive or resistant .
Geographical distribution
The distribution of the genospecies of B. burgdorferi in Germany differs depending on the region. However, there is only limited study material on this. The most common is B. afzelii (about 30%), followed by B. garinii (about 20%), B. valaisiana (about 13%) and B. burgdorferi sensu stricto. (about 7%). About 10% of Borrelia in ticks cannot be assigned.
In the USA the species B. burgdorferi sensu stricto occurs predominantly , which is also present in Europe. Because of the greater heterogeneity of the European genospecies, the American studies on pathogenesis , diagnosis and treatment as well as vaccine development cannot be applied in all areas.
swell
literature
- K. Tilly, PA Rosa, PE Stewart: Biology of infection with Borrelia burgdorferi. In: Infectious disease clinics of North America. Volume 22, Number 2, June 2008, pp. 217-34, v, ISSN 0891-5520 . doi: 10.1016 / j.idc.2007.12.013 . PMC 2440571 (free full text). (Review).
- J. Wu, EH Weening et al. a .: Invasion of eukaryotic cells by Borrelia burgdorferi requires? (1) integrins and Src kinase activity. In: Infection and Immunity . Volume 79, Number 3, March 2011, pp. 1338-1348, ISSN 1098-5522 . doi: 10.1128 / IAI.01188-10 . PMID 21173306 . PMC 3067508 (free full text).
Individual evidence
- ↑ a b c d Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 3-8274-0566-1 , pp. 349, 597-600, 971.
- ↑ VP Mursic u. a .: Formation and cultivation of Borrelia burgdorferi spheroplast-L-form variants. In: Infection. Volume 24, No. 3, 1996, pp. 218-226. PMID 8811359 .
- ↑ Joachim Gruber: Neuroborreliosis: Some Backgrounds for the Course of the Disease and Long Duration of Treatment. In: Lyme Disease Information . February 1, 2008, accessed July 29, 2014 .
- ↑ a b c A. G. Barbour: Isolation and cultivation of Lyme disease spirochetes. In: The Yale journal of biology and medicine. Volume 57, No. 4, July-August 1984, pp. 521-525, ISSN 0044-0086 . PMID 6393604 . PMC 2589996 (free full text).
- ^ JE Posey, FC Gherardini: Lack of a role for iron in the Lyme disease pathogen . In: Science . Volume 288, No. 5471, June 2000, pp. 1651-1653. PMID 10834845 .
- ↑ Matthias Redenbach, Josef Altenbuchner: Why do some bacteria have linear chromosomes and plasmids? In: Biospectrum. Volume 8, No. 2, 2002, pp. 158-163. PDF
- ↑ a b G. Baranton, D. Postic u. a .: Delineation of Borrelia burgdorferi sensu stricto, Borrelia garinii sp. nov., and group VS461 associated with Lyme borreliosis. In: International journal of systematic bacteriology. Volume 42, No. 3, July 1992, pp. 378-383, ISSN 0020-7713 . doi: 10.1099 / 00207713-42-3-378 . PMID 1380285 .
- ↑ a b c S. J. Cutler, CO Akintunde u. a .: Successful in vitro cultivation of Borrelia duttonii and its comparison with Borrelia recurrentis. In: International journal of systematic bacteriology. Volume 49, No. 4, October 1999, pp. 1793-1799, ISSN 0020-7713 . doi: 10.1099 / 00207713-49-4-1793 . PMID 10555362 .
- ^ A b Jean Euzéby, Aidan C. Parte: Genus Borrelia. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved May 6, 2020 .
- ↑ Approved Lists of Bacterial Names . In: VBD Skerman, Vicki McGowan, PHA Sneath (Ed.): International journal of systematic bacteriology . tape 30 , no. 1 , 1980, p. 225-420 , doi : 10.1099 / 00207713-30-1-225 ( sgmjournals.org [PDF; 17.0 MB ; accessed on April 13, 2014]). PDF, 17.0 MB ( Memento of the original from January 22, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Jean Euzéby, Aidan C. Parte: Some names included in the category Candidatus. In: LPSN . Retrieved July 29, 2014 .
