Spirochaete
Encyclopedia
Spirochaetes belong to a phylum of distinctive Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

 bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, which have long, helically
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...

 coiled (spiral-shaped) cells. Spirochaetes are chemoheterotrophic in nature, with lengths between 5 and 250 µm and diameters around 0.1-0.6 µm.

Spirochaetes are distinguished from other bacterial phyla by the location of their flagella
Flagellum
A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...

, sometimes called axial filaments, which run lengthwise between the bacterial inner membrane and outer membrane in periplasmic space
Periplasmic space
The periplasmic space or periplasm is a space between the peptidoglycan cell wall and inner membrane of Gram-negative bacteria or the equivalent space outside the inner membrane of Gram-positive bacteria. It may constitute up to 40% of the total cell volume in Gram-negative species, and is...

. These cause a twisting motion which allows the spirochaete to move about. When reproducing, a spirochaete will undergo asexual transverse binary fission.

Most spirochaetes are free-living and anaerobic
Anaerobic organism
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...

, but there are numerous exceptions.

Classification

The spirochaetes are divided into three families (Brachyspiraceae
Brachyspiraceae
Brachyspiraceae is a family of spirochaetes.Spirochetosis of the appendix, caused by Brachyspira aalborgi, can present as acute appendicitis. One study showed spirochetosis in 0.7% of all appendicies removed for clinical acute appendicitis....

, Leptospiraceae
Leptospiraceae
Leptospiraceae is a family of spirochetes.It includes the genus Leptospira....

, and Spirochaetaceae
Spirochaetaceae
Spirochaetaceae is a family of spirochetes most notable for the genus that causes Lyme disease and relapsing fever....

), all placed within a single order (Spirochaetales). Disease-causing members of this phylum include the following:
  • Leptospira
    Leptospira
    Leptospira is a genus of spirochaete bacteria, including a small number of pathogenic and saprophytic species...

    species, which causes leptospirosis
    Leptospirosis
    Leptospirosis is caused by infection with bacteria of the genus Leptospira, and affects humans as well as other mammals, birds, amphibians, and reptiles.The...

  • Borrelia burgdorferi
    Borrelia burgdorferi
    Borrelia burgdorferi is a species of Gram negative bacteria of the spirochete class of the genus Borrelia. B. burgdorferi is predominant in North America, but also exists in Europe, and is the agent of Lyme disease....

    , which causes Lyme disease
    Lyme disease
    Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

  • Borrelia recurrentis
    Borrelia recurrentis
    Borrelia recurrentis is a species of Borrelia.It can be associated with relapsing fever. B. recurrentis is usually transmitted from person to person via the human body louse....

    , which causes relapsing fever
    Relapsing fever
    Relapsing fever is an infection caused by certain bacteria in the genus Borrelia. It is a vector-borne disease that is transmitted through the bites of lice or soft-bodied ticks.-Louse-borne relapsing fever:...

  • Treponema pallidum
    Treponema pallidum
    Treponema pallidum is a species of spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. The treponemes have a cytoplasmic and outer membrane...

    subspecies pallidum, which causes syphilis
    Syphilis
    Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...

  • Treponema pallidum
    Treponema pallidum
    Treponema pallidum is a species of spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. The treponemes have a cytoplasmic and outer membrane...

    subspecies pertenue, which causes yaws
    Yaws
    Yaws is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pallidum pertenue...

  • Brachyspira pilosicoli
    Brachyspira pilosicoli
    Brachyspira pilosicoli is a gram-negative spiral-shaped obligate anaerobe bacterium. It is a member of the Spirochaetes family. The bacterium is loosely coiled and is 6-11µm long. It has several flagellae, inserted at either pole of the cell, and a lipopolysaccharide cell wall. It causes intestinal...

    and Brachyspira aalborgi, which cause intestinal spirochetosis
    Intestinal spirochetosis
    Intestinal spirochetosis, also intestinal spirochetes, colonic spirochetosis and colonic spirochetes, is an infection of the colonic-type mucosa with spirochete microorganisms.-Symptoms:...



Cavalier-Smith has postulated that the Spirochaetes belong in a larger clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 called Gracilicutes
Gracilicutes
Gracilicutes is a controversial taxon in Bacterial taxonomy.Traditionally Gram staining results were most commonly used as a classification tool, consequently until the advent of molecular phylogeny, the Kingdom Prokaryotae was divided into four divisions,*...

.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)

and the phylogeny is based on 16S rRNA-based LTP release 106 by The All-Species Living Tree Project 
Notes:

♦ Type strain lost or not available

♪ Prokaryotes where no pure (axenic
Axenic
In biology, axenic describes a culture of an organism that is entirely free of all other "contaminating" organisms. The earliest axenic cultures were of bacteria or unicellular eukaryotes, but axenic cultures of many multicellular organisms are also possible...

) cultures are isolated or available, i. e. not cultivated or can not be sustained in culture for more than a few serial passages

♠ Strains found at the National Center for Biotechnology Information
National Center for Biotechnology Information
The National Center for Biotechnology Information is part of the United States National Library of Medicine , a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper...

 (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)

Historical

Salvarsan, the first partially organic antimicrobial drug in medical history, was effective against spirochaetes only and was primarily used to cure syphilis
Syphilis
Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...

.

See also

  • Flagellum
    Flagellum
    A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...

  • Treponema pallidum
    Treponema pallidum
    Treponema pallidum is a species of spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. The treponemes have a cytoplasmic and outer membrane...

  • Lyme disease microbiology
    Lyme disease microbiology
    Lyme disease, or borreliosis, is caused by Gram negative spirochetal bacteria from the genus Borrelia, which has at least 37 known species, 12 of which are Lyme related, and an unknown number of genomic strains...

  • Borrelia
    Borrelia
    Borrelia is a genus of bacteria of the spirochete phylum. It causes borreliosis, a zoonotic, vector-borne disease transmitted primarily by ticks and some by lice, depending on the species...

  • Bacteriology
    Bacteriology
    Bacteriology is the study of bacteria. This subdivision of microbiology involves the identification, classification, and characterization of bacterial species...

  • Prokaryote
    Prokaryote
    The prokaryotes are a group of organisms that lack a cell nucleus , or any other membrane-bound organelles. The organisms that have a cell nucleus are called eukaryotes. Most prokaryotes are unicellular, but a few such as myxobacteria have multicellular stages in their life cycles...


External links

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