Ureaplasma parvum

Ureaplasma parvum
Scientific classification
Domain: Bacteria
Phylum: Mycoplasmatota
Class: Mollicutes
Order: Mycoplasmatales
Family: Mycoplasmataceae
Genus: Ureaplasma
Species:
U. parvum
Binomial name
Ureaplasma parvum
Robertson et al. 2002

Ureaplasma parvum is a species of Ureaplasma, a genus of bacteria belonging to the family Mycoplasmataceae.[1]

Ureaplasma parvum was formerly known as Ureaplasma urealyticum biovar 1.[2] Ureaplasma parvum has been identified as being a commensal in the uterus as part of the microbiome in healthy women of reproductive age.[3][4]

In addition, this pathogen may latently infect the chorionic villi tissues of pregnant women, thereby impacting pregnancy outcome.[5]

Classification

Ureaplasma spp. are one of the smallest known clonal bacteria. They are closely related to mycoplasmas as they lack a peptidoglycan cell wall, metabolize cholesterol, and require urea for ATP synthesis.[6] The Ureaplasma genus has 14 serotypes that are classified based on the 16S rRNA gene, the urease gene, and the multiple-banded antigen (MBA) gene.[7] U. parvum has four serotypes (-1, -3, -6, -14) that were differentiated by variations in the MBA gene, a Ureaplasma surface antigen protein.[8] Although U. parvum is known to be a commensal microorganism within healthy humans, its ability to become pathogenic may be due to its ability to easily acquire new genes via horizontal gene transfer (HGT).[9] Sequencing of U. parvum samples isolated from clinical patients reveals a much more diverse set of strains (at least 19), suggesting that further methods of classifying U. parvum should be investigated.[9]

Clinical relevance

The clinical implications concerning the pathogenicity of U. parvum have yet to be determined because of its recent establishment as a separate species from U. urealyticum. Due to the species heterogeneity in Ureaplasma spp. not being noted in clinical studies prior to their distinction from each other, it is possible that U. urealyticym is disproportionately overrepresented compared to U. parvum.[6] As a consequence, interpreting data on Ureaplasma parvum can be difficult since there are currently few studies that differentiate between the Ureaplasma spp. Therefore, there is little substantial evidence that U. parvum causes any of the diseases that have been associated with U. urealyticym, specifically inflammatory vulvovaginitis, male infertility and non-gonococcal urethritis (NGU), female urethritis and urethral pain syndrome, pelvic inflammatory disease, cervicitis, ectopic pregnancy, and female infertility.[10] It is important for future studies to accurately differentiate between U. urealyticum and U. parvum, as this will aid in the etiological analysis of NGU and other diseases.

Ureaplasma spp. lack a cell wall and are therefore resistant to antimicrobials that specifically attack the cell wall. For this reason, Ureaplasma spp. are particularly difficult to diagnose and eradicate, and unnecessary treatment can further encourage antimicrobial resistance.[11] As a result, extensive testing and treatment of the Ureaplasma spp. is not always recommended.[11]

Commensalism

Ureaplasma parvum is commensal in both males and females, where it attaches itself to the mucosal lining of the urogenital tract. Damage to mucosal linings results in the relocation of Ureaplasma spp. to other physiological areas of the body, which can lead to infection and disease.[12] U. parvum has been investigated as an opportunistic pathogen, however current studies question its contribution to urogenital infections.[13] For example, a study conducted by Rumyantseva et al [14] showed that in female patients with varying vaginal microflora, U. parvum was the most prevalent mycoplasma. In normal vaginal microflora, 43.5% of samples were U. Parvum positive. Bacterial vaginosis and aerobic vaginitis samples were 59.9% and 23.9% U. Parvum positive, respectively. This study supports the symbiotic considerations between vaginal microflora (primarily normal and bacterial vaginosis) and mycoplasma such as U. parvum.

Current studies: Ureaplasma parvum in males

Ureaplasma parvum (and U. urealyticum) have been linked to nongonococcal urethritis (NGU), but the Ureaplasma spp. have also been found in many healthy men, allowing for considerable skepticism that the two are correlated. Similarly, links to prostatitis and infertility are difficult to establish due to its presence in control groups.[15] In andrology studies, the presence of U. parvum in semen has been found to be significant. Various Ureaplasma spp. isolates have been detected in semen via polymerase chain reaction (PCR) and immunofluorescent antibody assay. In 36.6% of washed samples, U. parvum was present.[16] Andrology studies surrounding U. parvum demonstrated that the bacteria can remain on the spermatozoa even after washing.

Current studies: Ureaplasma parvum in females

Current research indicates that U. parvum infections can cause pregnancy complications. In pregnant women with an intra-amniotic infection, U. parvum is the most common bacterium found. Ureaplasma spp. generally causes a more severe inflammatory response than other microbial infections. These infections can lead to preterm birth, maternal and fetal inflammation, placental inflammation (chorioamnionitis), and neonatal mortality.[17] One study [18] found that amniotic inoculation with a clinically isolated U. parvum serovar 14 causes preterm birth in animal models, while serovar 3 causes a low rate of preterm birth but a higher rate of neonatal mortality. Studies are ongoing.

References

  1. Oshima K, Nishida H (May 2008). "Detection of the genes evolving under Ureaplasma-specific selection". Journal of Molecular Evolution. 66 (5): 529–32. Bibcode:2008JMolE..66..529O. doi:10.1007/s00239-008-9106-4. PMID 18414924. S2CID 25734066.
  2. Kong F, Ma Z, James G, Gordon S, Gilbert GL (March 2000). "Species identification and subtyping of Ureaplasma parvum and Ureaplasma urealyticum using PCR-based assays". Journal of Clinical Microbiology. 38 (3): 1175–9. doi:10.1128/JCM.38.3.1175-1179.2000. PMC 86368. PMID 10699016.
  3. Yarbrough VL, Winkle S, Herbst-Kralovetz MM (2014). "Antimicrobial peptides in the female reproductive tract: a critical component of the mucosal immune barrier with physiological and clinical implications". Human Reproduction Update. 21 (3): 353–77. doi:10.1093/humupd/dmu065. PMID 25547201.
  4. Mor G, Kwon JY (October 2015). "Trophoblast-microbiome interaction: a new paradigm on immune regulation". American Journal of Obstetrics and Gynecology. 213 (4 Suppl): S131-7. doi:10.1016/j.ajog.2015.06.039. PMC 6800181. PMID 26428492.
  5. Contini C, Rotondo JC, Magagnoli F, Maritati M, Seraceni S, Graziano A, et al. (January 2018). "Investigation on silent bacterial infections in specimens from pregnant women affected by spontaneous miscarriage". Journal of Cellular Physiology. 234 (1): 100–107. doi:10.1002/jcp.26952. PMID 30078192.
  6. 1 2 Beeton ML, Payne MS, Jones L (September 2019). "The Role of Ureaplasma spp. in the Development of Nongonococcal Urethritis and Infertility among Men". Clinical Microbiology Reviews. 32 (4). doi:10.1128/CMR.00137-18. PMC 6750135. PMID 31270127.
  7. Kim MS, Lee DH, Kim TJ, Oh JJ, Rhee SR, Park DS, Yu YD (January 2021). "The role of Ureaplasma parvum serovar-3 or serovar-14 infection in female patients with chronic micturition urethral pain and recurrent microscopic hematuria". Translational Andrology and Urology. 10 (1): 96–108. doi:10.21037/tau-20-920. PMC 7844479. PMID 33532300.
  8. Kong F, Ma Z, James G, Gordon S, Gilbert GL (September 2000). "Molecular genotyping of human Ureaplasma species based on multiple-banded antigen (MBA) gene sequences". International Journal of Systematic and Evolutionary Microbiology. 50 Pt 5 (5): 1921–1929. doi:10.1099/00207713-50-5-1921. PMID 11034506.
  9. 1 2 Paralanov V, Lu J, Duffy LB, Crabb DM, Shrivastava S, Methé BA, et al. (May 2012). "Comparative genome analysis of 19 Ureaplasma urealyticum and Ureaplasma parvum strains". BMC Microbiology. 12 (1): 88. doi:10.1186/1471-2180-12-88. PMC 3511179. PMID 22646228.
  10. Taylor-Robinson D (November 2017). "Mollicutes in vaginal microbiology: Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Mycoplasma genitalium". Research in Microbiology. 168 (9–10): 875–881. doi:10.1016/j.resmic.2017.02.009. PMID 28263902.
  11. 1 2 Horner P, Donders G, Cusini M, Gomberg M, Jensen JS, Unemo M (November 2018). "Should we be testing for urogenital Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum in men and women? - a position statement from the European STI Guidelines Editorial Board". Journal of the European Academy of Dermatology and Venereology. 32 (11): 1845–1851. doi:10.1111/jdv.15146. hdl:10067/1554670151162165141. PMID 29924422. S2CID 49313037.
  12. Gupta A (2019-06-20). "Mycoplasma and Ureaplasma – The big conundrum". Walk In Gyn Care. Retrieved 2021-04-19.
  13. Zimmerman CU, Stiedl T, Rosengarten R, Spergser J (March 2009). "Alternate phase variation in expression of two major surface membrane proteins (MBA and UU376) of Ureaplasma parvum serovar 3". FEMS Microbiology Letters. 292 (2): 187–93. doi:10.1111/j.1574-6968.2009.01505.x. PMID 19220471.
  14. Rumyantseva T, Khayrullina G, Guschin A, Donders G (March 2019). "Prevalence of Ureaplasma spp. and Mycoplasma hominis in healthy women and patients with flora alterations". Diagnostic Microbiology and Infectious Disease. 93 (3): 227–231. doi:10.1016/j.diagmicrobio.2018.10.001. hdl:10067/1585870151162165141. PMID 30344067.
  15. Beeton ML, Payne MS, Jones L (September 2019). "The Role of Ureaplasma spp. in the Development of Nongonococcal Urethritis and Infertility among Men". Clinical Microbiology Reviews. 32 (4): e00137–18, /cmr/32/4/CMR.00137–18.atom. doi:10.1128/CMR.00137-18. PMC 6750135. PMID 31270127.
  16. Knox CL, Allan JA, Allan JM, Edirisinghe WR, Stenzel D, Lawrence FA, et al. (October 2003). "Ureaplasma parvum and Ureaplasma urealyticum are detected in semen after washing before assisted reproductive technology procedures". Fertility and Sterility. 80 (4): 921–9. doi:10.1016/S0015-0282(03)01125-7. PMID 14556813.
  17. von Chamier M, Allam A, Brown MB, Reinhard MK, Reyes L (2012-08-29). Kanellopoulos-Langevin C (ed.). "Host genetic background impacts disease outcome during intrauterine infection with Ureaplasma parvum". PLOS ONE. 7 (8): e44047. Bibcode:2012PLoSO...744047V. doi:10.1371/journal.pone.0044047. PMC 3430619. PMID 22952869.
  18. Motomura K, Romero R, Xu Y, Theis KR, Galaz J, Winters AD, et al. (June 2020). Ballard JD (ed.). "Intra-Amniotic Infection with Ureaplasma parvum Causes Preterm Birth and Neonatal Mortality That Are Prevented by Treatment with Clarithromycin". mBio. 11 (3): e00797–20, /mbio/11/3/mBio.00797–20.atom. doi:10.1128/mBio.00797-20. PMC 7315120. PMID 32576673.
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