''Ureaplasma urealyticum'' is a bacterium belonging to the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Ureaplasma'' and the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mycoplasmataceae in the order Mycoplasmatales. This family consists of the genera '' Mycoplasma'' and '' Ureaplasma''. Its type strain is T960. There are two known

biovar A biovar is a variant prokaryotic Strain (biology), strain that differs physiologically or biochemically from other strains in a particular species. Morphovars (or morphotypes) are those strains that differ morphologically. Serovars (or serotypes ...

s of this species; T960 and 27. These strains of bacteria are commonly found as commensals in the urogenital tracts of human beings, but overgrowth can lead to infections that cause the patient discomfort. Unlike most bacteria, ''Ureaplasma urealyticum'' lacks a

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

making it unique in physiology and medical treatment.

Classification

The six recognised ''Ureaplasma''

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

have a GC content of 27 to 30 percent and a genome size ranging from 0.76 to 1.17 million base pairs, and

cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...

is required for growth. A defining characteristic of the genus is that they perform

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

, which creates ammonia as a product. Some strains originally classified as ''U. urealyticum'' should be treated as a new species, '' U. parvum''. Both strains of U''reaplasma urealyticum'' have had their DNA sequenced, using a PCR amplification and dideoxy termination method. Their sequences can be accessed through public records and databases. Most of the16S rDNA sequence of the two strains constitute the exact same nucleotides bases (97.3% homology), yet small differences have been acknowledged. Due to the direct similarity and the increased variation in other species of ''Ureaplasma'', it is thought that the two strains of ''Ureaplasma urealyticum'' (T960 and 27) have evolutionary diverged together. In the same study conducted, using the same 16s rDNA aligned sequences, they concluded all the mammalian strains diverged and coevolved with their corresponding species (canine, feline, human, bovine) during the Cretaceous period. It was found that the most closely related species strain of ''Ureaplasma'' to ''Ureaplasma urealyticum'' was ''Ureaplasma diversum'' (isolated from bovine).

Gram staining

U. urealyticum represents one of the 14 distinct types within the Ureaplasma genus. Classified within the Mollicutes class, Ureaplasma species have undergone significant evolutionary adaptations from their Gram-positive bacterial ancestors, a phenomenon termed degenerative evolutions (Kallapur, Suhas G, et al 2013). This evolutionary trajectory has resulted in the loss of the peptidoglycan cell wall, a hallmark characteristic of Gram-positive bacteria. Despite this evolutionary divergence, instances have been reported where U. urealyticum, upon gram staining, exhibited the same characteristics as Gram-negative bacteria. Notably, despite such staining outcomes, it is imperative to recognize that the U. urealyticum remains a Gram-Positive bacterium, This discrepancy underscores the importance of discerning between staining outcomes and bacterial classification (“Ureaplasma Urealyticum.” Microbewiki).

Treatment

As stated previously, since these bacteria are still considered Gram-positive, and lack a cell wall, the most versatile antibiotic that can’t be used is penicillin. Since these antibiotics attack the cell wall of a bacterium, they can not be used for this type of infection. The reason that many individuals get this infection can be damage to the uterus wall lining, causing the bacteria to thrive in a carbon-rich environment. Unfortunately, it was found from trials that many of the antibiotics that we utilize on a day-to-day basis for urinary tract infections do not affect the bacteria due to lacking a cell wall. Yet, the types of antibiotics that can be used are quinolones, tetracyclines, and macrolides, since they affect a large part of the mycoplasma family of bacteria where U. urealyticum falls under. Yet, it is not recommended to be used a lot because these bacteria can develop resistance to these antibiotics fairly fast. Secondly, other drugs that have β-lactamases are infective to treat infection because of how fast the bacteria's circular genome can mutate (Fan et al. 2023). However, there are new movements to use Azithromycin to treat these infections. This is a therapeutic that can be taken orally, once ingested our macrophages, which are part of our immune system, take up the antibiotic and deliver it to the sites of infection (Fan et al. 2023). This helps control the infection where the bacteria grows, additionally, it is also a great alternative to when a mother is pregnant so it does not cause harm to the fetus since It's using our immune system to help defend the fetus and the mother's body.

Testing on agar

To test for this bacterium, an agar plate, which is 10B broth, should be used on U. urealyticum. Since these bacteria love to grow in mostly acidic places, the bacteria should go under microdilution MIC dilution to get a pH color change. If the dilution color changes to red it indicates that there is presence of U. urealyticum in the sample. After this, it should be transferred to the 10B Broth, where once placed it will turn yellow, but then slowly change the color to pink. This helps to indicate the growth of the bacterium(Waites, Ken B, et al 2012). The reason it can grow on this 10B Broth is because it has a lot of nutrients that let the bacteria grow from heart infusion to yeast extract, yet, it also has urea to help the bacteria to hydrolyze it and with hydrolyzing it causes the release of ammonia that causes the broth to change to a pink color
10B Broth - Thermo Fisher Scientific
. The reason for this is that it loves to live in urea-rich environments. It's the same reason why in clinics, they take urine samples or vaginal swabs to be sent to the labs to run this test on 10B broth.

Clinical relevance

''Ureaplasma urealyticum'' can cause urethritis and may cause

bacterial vaginosis Bacterial vaginosis (BV) is an infection of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urina ...

Infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

can occur in extragenital sites. A common symptom associated with these infections is the "fishy" smell that is created due to the production of ammonia by the hydrolysis of urea. Patients should confirm diagnosis with a doctor. The bacterium has high correlations with the Human Papillomavirus (HPV). It has also been linked to

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

in both males and females. In addition, this pathogen may latently infect the chorionic villi tissues of pregnant women, thereby impacting pregnancy outcome. Issues that arise from ''Ureaplasma urealyticum'' infections during pregnancy include preterm birth and impacted embryonic development. Some patients have given birth to children subjected to bronchopulmonary dysplasia, Intraventricular hemorrhage, and necrotizing enterocolitis. Patients can evolve resistances to normal

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

treatments due to the distinctive physiology of these organisms. In the Western World, approximately 40% of ''Ureaplasma'' species are resistant to fluoroquinolones (i.e. ciprofloxacin). Patients who are pregnant have further limitations on the treatment course of a ''Ureaplasma urealyticum'' infection, making it far harder to successfully cure.

References

External links

*
Ureaplasma Genome Projects
fro
Genomes OnLine Database

Type strain of ''Ureaplasma urealyticum'' at Bac''Dive'' – the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q137110 urealyticum Sexually transmitted diseases and infections Infectious causes of cancer Infections with a predominantly sexual mode of transmission Bacterial vaginosis Bacteria described in 1974