Brachyspira

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Brachyspira
Systematics
Domain : Bacteria (bacteria)
Department : Spirochaetae
Class : Spirochaetes
Order : Spirochaetales
Family : Brachyspiraceae
Genre : Brachyspira
Scientific name of the  family
Brachyspiraceae
Paster et al. 2012
Scientific name of the  genus
Brachyspira
Hovind-Hougen et al. 1983

The spirochetes - genus Brachyspira was first described in the 1982nd It is the only genus in the Brachyspiraceae family . All representatives of these gram-negative bacteria have a low GC content and are anaerobic , but can tolerate oxygen. Some species are pathogenic . The infectious diseases caused belong to the intestinal spirochetoses. All species can be found in the intestines of various animals (e.g. pigs) and humans.

features

Appearance

The cells are elongated and coiled up in a spiral, as is also the case with closely related spirochetes . The diameter is in the range of 2-11 µm in length and 0.2-0.4 µm in width. The cell ends are rounded or pointed, but not hook-shaped, as is typical for Leptospira . In growing cultures, chains with a length of three or more cells are sometimes observed, otherwise the cells are present individually. Under unfavorable conditions, spherical cells are formed. The periplasmic flagella (endoflagella) overlap in the middle of the cell. They give the cells the ability to actively move . In the Gram stain they behave negatively.

Growth and metabolism

Brachyspira is chemo - heterotrophic . The metabolism is strictly anaerobic but aerotolerant, i. H. the species is under anaerobic conditions - ie under exclusion of oxygen - growth . The presence of oxygen neither promotes nor inhibits its growth. In the metabolism of substances and energy , various carbohydrates and amino sugars are used in one fermentation . Glucose , fructose , galactose , lactose , maltose , mannose and trehalose can be used in fermentation by some species (e.g. Brachyspira aalborgi , B. hyodysenteriae , B. innocens ) . Acetate , H 2 and CO 2 occur as metabolic end products . Also, ethanol can result in various types.

Chemotaxonomy

The representatives of the Brachyspiraceae family belong to the bacteria with a low GC content , i.e. a low proportion of the nucleobases guanine and cytosine in the bacterial DNA . The GC content for the genus is 24-28  mole percent . The GC content of the type species B. aalborgi is 27.1 mol percent. The murein layer in the cell wall contains the diamino acid L - ornithine as a diagnostically important amino acid. The antigens can be used to differentiate between the different species ; these are the lipopolysaccharides in the outer membrane .

Occurrence

Brachyspira species are bound to a host and are not found in the wild. They occur in the intestines of various animals (e.g. pigs) and humans.

Systematics

History of Taxonomy

The pathogen causing pig dysentery (now: B. hyodysenteriae ) and another non-pathogenic bacterial strain also found in pig intestines were assigned to the genus Treponema after their discovery in 1972 . On the basis of research results of the DNA-DNA hybridization , the apathogenic strain was separated from the species Treponema hyodysenteriae and assigned to the new species Treponema innocens . Various further investigations (including through 16S rRNA sequences) showed a not close relationship to the type species of Treponema ( T. pallidum ) and led to the introduction of a new genus, Serpula . This genus, consisting of Serpula hyodysenteriae and Serpula innocens , was renamed Serpulina in 1992 , because there was already a genus of fungi with the name Serpula . The genus Brachyspira was already established in 1982 with the species Brachyspira aalborgi by Hovind-Hougen u. a. Are defined. Further investigations of the 16S rRNA showed a high relationship to the genus Serpulina and in 1997 all species of Serpulina were finally placed in the genus Brachyspira .

Current system

Brachyspira is the only genus and thus also the type genus of the Brachyspiraceae family. The family was founded in 2012 by Paster u. a. established. It is in the order of the Spirochaetales , which includes three more in addition to this family: Brevinemataceae , Leptospiraceae and Spirochaetaceae . According to new phylogenetic studies from 2013 by Gupta et al. a. It was proposed to the representatives of these spirochete families to raise the families to the rank of an order because of their clear differences (see also the proposal for a modified systematics of the Spirochaetaceae ). This would make the Brachyspiraceae the only family in the new order Brachyspiriales. Such changes are usually only recognized with the new edition of the important reference work on the phylogenetic systematics of bacteria , Bergey's Manual of Systematic Bacteriology .

Types and Medical Significance

Seven species are currently included in the genus Brachyspira (as of 2014), B. aalborgi is the type species.

apathogenic, has been detected in the human intestine
Diarrhea pathogens in chickens
the causative agent of swine dysentery
  • Brachyspira innocens ( Kinyon & Harris et al. 1979) Ochiai et al. 1998 (Synonym: Serpulina innocens )
apathogenic, has been demonstrated in pigs
apathogenic, has been demonstrated in pigs
apathogenic, has been demonstrated in pigs and rats
the causative agent of the porcine intestinal spirochaetosis

swell

literature

  • Michael Rolle, Anton Mayr (ed.): Medical microbiology, infection and epidemic theory . 8th edition. Enke Verlag, Stuttgart 2006, ISBN 3-8304-1060-3 .
  • Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria . 3. Edition. tape 7 : Delta and Epsilon Subclasses. Deeply Rooting Bacteria . Springer-Verlag, New York 2006, ISBN 0-387-30747-8 , pp. 330-358 , doi : 10.1007 / 0-387-30747-8 .

Individual evidence

  1. ↑ a b war, NR; Ludwig, W .; Whitman, WB; Hedlund, BP; Paster, BJ; Staley, JT; Ward, N .; Brown, D .; Parte, A .: Bergey's Manual of Systematic Bacteriology. Volume 4: The Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres, Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and Planctomycetes . Springer, 2010, ISBN 978-0-387-68572-4 , pp. 457-467 .
  2. ↑ a b c d e f g Radhey S. Gupta, Sharmeen Mahmood, Mobolaji Adeolu: A Phylogenomic and Molecular Signature Based Approach for Characterization of the Phylum Spirochaetes and its Major Clades: Proposal for a Taxonomic Revision of the Phylum. In: Frontiers in Microbiology. Volume 4, No. 217, July 29, 2013, ISSN  1664-302X . doi: 10.3389 / fmicb.2013.00217 .
  3. ↑ a b c d e S. Ochiai, Y. Adachi, K. Mori: Unification of the genera Serpulina and Brachyspira, and proposals of Brachyspira hyodysenteriae comb. nov., Brachyspira innocens comb. nov. and Brachyspira pilosicoli comb. nov. In: Microbiology and immunology. Volume 41, No. 6, 1997, pp. 445-452, ISSN  0385-5600 . PMID 9251055 .
  4. ↑ a b K. Hovind-Hougen, A. Birch-Andersen u. a .: Intestinal spirochetosis: morphological characterization and cultivation of the spirochete Brachyspira aalborgi gen. nov., sp. nov. In: Journal of Clinical Microbiology. Volume 16, Number 6, December 1982, pp. 1127-1136, ISSN  0095-1137 . PMID 6186689 . PMC 272552 (free full text).
  5. ↑ Jean Euzéby, Aidan C. Part: Family Brachyspiraceae. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved August 1, 2014 .
  6. ^ Jean Euzéby, Aidan C. Parte: Genus Brachyspira. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved August 1, 2014 .