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''Chlamydia abortus'' is a species in

Chlamydiota The Chlamydiota (synonym Chlamydiae) are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of th ...

that causes abortion and fetal death in mammals, including humans. ''Chlamydia abortus'' was renamed in 1999 as ''

Chlamydophila psittaci ''Chlamydia psittaci'' is a lethal intracellular parasite, intracellular bacterial species that may cause Endemism, endemic Bird, avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include ...

'' along with all Chlamydiota except ''

Chlamydia trachomatis ''Chlamydia trachomatis'' (), commonly known as chlamydia, is a bacterium that causes chlamydia, which can manifest in various ways, including: trachoma, lymphogranuloma venereum, nongonococcal urethritis, cervicitis, salpingitis, pelvic inflamma ...

''. This was based on a lack of evident

glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...

production and on resistance to the

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

sulfadiazine Sulfadiazine is an antibiotic. Used together with pyrimethamine, a dihydrofolate reductase inhibitor, it is the treatment of choice for toxoplasmosis, which is caused by a protozoan parasite. It is a second-line treatment for otitis media, p ...

. In 1999 ''C. psittaci'' and ''C. abortus'' were recognized as distinct species based on differences of

pathogenicity In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

and

DNA–DNA hybridization In genomics, DNA–DNA hybridization is a molecular biology technique that measures the degree of genetic similarity between pools of DNA sequences. It is usually used to determine the genetic distance between two organisms and has been used ex ...

. In 2015, this new name was reverted to Chlamydia.

In humans

There are approximately one or two cases of chlamydiosis diagnosis in pregnant women in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

per year. Typically transmission occurs from contact with livestock who have recently given birth. The true prevalence in humans is unknown because

serological Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given mi ...

antibody An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

tests are unable to distinguish between ''C. abortus'' and other more common species such as ''

''.

In other animals

''Chlamydia abortus'' is endemic among

ruminant Ruminants (suborder Ruminantia) are ungulate, hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach prior to digestion, principally ...

s such as cows and sheep and has been associated with

abortion Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pregn ...

in a horse, a rabbit, guinea pigs, mice, pigs and humans. Infected females shed bacteria near the time of ovulation, so ''C. abortus'' is transmitted orally and sexually among mammals. All ''C. abortus'' strains were isolated or PCR-amplified from the

placenta The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mater ...

or fetal organs after spontaneous abortion. ''C. abortus'' infection generally remains unapparent until an animal aborts late in gestation or gives birth to a weak or dead fetus. ''Chlamydia abortus'' has been isolated from birds.

Genome structure

''Chlamydia abortus'' has a relatively small

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

that contains 1.14 Mbp with 961

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

coding genes.

In humans

In other animals

Genome structure

References

Further reading