Ureaplasma urealyticum
| Ureaplasma urealyticum | ||||||||||||||
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| Scientific classification | ||||||||||||||
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| Binomial name | ||||||||||||||
| Ureaplasma urealyticum Shepard et al., 1974 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Fatimo Biobaku M.B.B.S [2]
Keywords: Ureaplasma parvum, U.urealyticum biovar 1, U.urealyticum biovar 2, T-strain Mycoplasma, Ureaplasmal pneumonia
Overview
Historical Perspective
T-strain mycoplasma (now known as Ureaplasma urealyticum) was first discovered in the human urogenital tract in 1954 by Shepard et al.[1][2] In 1974, this tiny (T)-strain mycoplasma was named Ureaplasma urealyticum.[2][1] U. urealyticum was further subdivided into two biotypes; biovar 1 and biovar 2. Ureaplasma urealyticum biovar 1 was later designated as a separate specie called U. parvum following phylogenetic analysis done in 1999, but the biovar 2 strain retained its designation as U. urealyticum.[1] Investigations carried out in the mid 1970's by Tafari et al. described the isolation of Ureaplasma urealyticum from the lungs of stillborn infants with pneumonitis, and it is one of the earliest investigations that suggested the possible pathogenic role of U. urealyticum in neonatal disease.[3] Waites et al. reported the first case of suspected neonatal ureaplasmal pneumonia with sepsis and persistent pulmonary hypertension of the newborn in the 1980's.[4] Several case reports are now available in the literature documenting the isolation of Ureaplasma urealyticum and Ureaplasma parvum in fetal lung tissue, cord blood, pulmonary secretions, pleural fluid, lung tissue, and blood stream of neonates with pneumonia.[3]
Pathophysiology
Pathogenesis
The role of Ureaplasma infection in preterm delivery
- Ureaplasma species are considered to be of low virulence, and 40-80% of healthy women have ureaplasma species (commonly U. urealyticum and U. parvum) in their genital tract.[5][6][3][7]
- Controversial evidence exists supporting the association between genital colonization with ureaplasma species and complications of pregnancy such as preterm delivery.[8]
- Lactobacilli help maintain the vaginal acidity, preventing the invasion of bacteria. However, the urease activity of ureaplasma species such as U. urealyticum increases the pH of the vagina via the hydrolysis of urea into carbon dioxide and ammonia. This increases the susceptibility to mixed infection with other pathogenic bacteria.[8]
- These pathogens induce the secretion of pro-inflammatory cytokines such as IL-1, TNF-α, IL-6, and chemokines such as IL-8, leading to the recruitment of leukocytes and production of prostaglandins. Uterine stimulation by prostaglandins result in preterm delivery.[8]
- Ureaplasmal lipoprotein also induce apoptosis, and it is possible that the apoptotic cells sustain genital tract inflammation which promote preterm delivery.[8]
- Studies have also shown a higher rate of vaginal infection with ureaplasma species in women with preterm deliveries compared to those with full-term deliveries.[8]
Neonatal infection and the role of Ureaplasma species
- Ureaplasma urealyticum and U. parvum are the most common organisms isolated from infected amniotic fluid and placenta, suggesting the potential role of ureaplasma species in the development of disseminated neonatal infection.[9][6][3][7]
- The infection is commonly acquired via vertical transmission by three main mechanisms:[3]
- Maternal placental infection with umbilical vessels involvement result in the hematogenous dissemination of infection in the neonate.
- Passage of the organisms into the fetal lung via an infected amniotic fluid. This could result in pneumonitis, bacteremia, or meningitis.
- Perinatal acquisition of infection following passage of the baby through an infected maternal birth canal.
- Preterm neonates are most commonly affected, and very low birth weight (VLBW) infants have been noted to have invasive ureaplasma infection.[7] Preterm infants weighing <5.5 pounds are nearly four times more likely to develop systemic infection compared to full term infants weighing above 5.5 pounds.
- There may also be an association between necrotising enterocolitis and ureaplasma colonization in preterm neonates.[6]
Colonization with Ureaplasma species and its association with urogenital infections
- There is no significant association between ureaplasma colonization of the lower genital tract and symptomatic urogenital infection in females.[10]
- The detection of Ureaplasma urealyticum and U. parvum in fluid samples obtained from the pouch of Douglas in 60% of women with lower urogenital tract Ureaplasma colonization confirms the fact that asymptomatic infection of the upper genital tract can occur in women following direct ascent of these organisms from the cervix and vagina to the sterile upper reproductive tract.[11]
- Some studies conducted in men show there is an association between Ureaplasma urealyticum and nongonococcal urethritis.[12][1][13] However, the pathogenic role of Ureaplasma urealyticum in nongonococcal urethritis is still not clear.[14][2]
- Men with higher bacterial load of U. urealyticum(≥5 x 103) in first-void urine were found to have higher leukocyte counts and symptomatic urethritis, and it has been suggested that there could be a positive correlation between the bacteria load of U. urealyticum and the development of inflammatory responses to the organism.[2]
Epidemiology and Demographics
Prevalence
Age
Gender
Race
Geographical Distribution
Risk Factors
Screening
Natural History, Complications, and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory findings
Microscopy
Molecular-based test
Treatment
Prevention
- ↑ 1.0 1.1 1.2 1.3 Deguchi T, Yoshida T, Miyazawa T, Yasuda M, Tamaki M, Ishiko H; et al. (2004). "Association of Ureaplasma urealyticum (biovar 2) with nongonococcal urethritis". Sex Transm Dis. 31 (3): 192–5. PMID 15076934.
- ↑ 2.0 2.1 2.2 2.3 Shimada Y, Ito S, Mizutani K, Sugawara T, Seike K, Tsuchiya T; et al. (2014). "Bacterial loads of Ureaplasma urealyticum contribute to development of urethritis in men". Int J STD AIDS. 25 (4): 294–8. doi:10.1177/0956462413504556. PMID 24047884.
- ↑ 3.0 3.1 3.2 3.3 3.4 Waites KB, Crouse DT, Cassell GH (1993). "Systemic neonatal infection due to Ureaplasma urealyticum". Clin Infect Dis. 17 Suppl 1: S131–5. PMID 8399903.
- ↑ Waites KB, Crouse DT, Philips JB, Canupp KC, Cassell GH (1989). "Ureaplasmal pneumonia and sepsis associated with persistent pulmonary hypertension of the newborn". Pediatrics. 83 (1): 79–85. PMID 2909979.
- ↑ Resch B, Gutmann C, Reiterer F, Luxner J, Urlesberger B (2016). "Neonatal Ureaplasma urealyticum colonization increases pulmonary and cerebral morbidity despite treatment with macrolide antibiotics". Infection. 44 (3): 323–7. doi:10.1007/s15010-015-0858-7. PMID 26518581.
- ↑ 6.0 6.1 6.2 Okogbule-Wonodi AC, Gross GW, Sun CC, Agthe AG, Xiao L, Waites KB; et al. (2011). "Necrotizing enterocolitis is associated with ureaplasma colonization in preterm infants". Pediatr Res. 69 (5 Pt 1): 442–7. doi:10.1203/PDR.0b013e3182111827. PMC 3968774. PMID 21258263.
- ↑ 7.0 7.1 7.2 Viscardi RM, Hashmi N, Gross GW, Sun CC, Rodriguez A, Fairchild KD (2008). "Incidence of invasive ureaplasma in VLBW infants: relationship to severe intraventricular hemorrhage". J Perinatol. 28 (11): 759–65. doi:10.1038/jp.2008.98. PMC 5334544. PMID 18596706.
- ↑ 8.0 8.1 8.2 8.3 8.4 Harada K, Tanaka H, Komori S, Tsuji Y, Nagata K, Tsutsui H; et al. (2008). "Vaginal infection with Ureaplasma urealyticum accounts for preterm delivery via induction of inflammatory responses". Microbiol Immunol. 52 (6): 297–304. doi:10.1111/j.1348-0421.2008.00039.x. PMID 18577163.
- ↑ Goldenberg RL, Andrews WW, Goepfert AR, Faye-Petersen O, Cliver SP, Carlo WA; et al. (2008). "The Alabama Preterm Birth Study: umbilical cord blood Ureaplasma urealyticum and Mycoplasma hominis cultures in very preterm newborn infants". Am J Obstet Gynecol. 198 (1): 43.e1–5. doi:10.1016/j.ajog.2007.07.033. PMC 2278008. PMID 18166302.
- ↑ Marovt M, Keše D, Kotar T, Kmet N, Miljković J, Šoba B; et al. (2015). "Ureaplasma parvum and Ureaplasma urealyticum detected with the same frequency among women with and without symptoms of urogenital tract infection". Eur J Clin Microbiol Infect Dis. 34 (6): 1237–45. doi:10.1007/s10096-015-2351-8. PMID 25717022.
- ↑ Kasprzykowska U, Elias J, Elias M, Mączyńska B, Sobieszczańska BM (2014). "Colonization of the lower urogenital tract with Ureaplasma parvum can cause asymptomatic infection of the upper reproductive system in women: a preliminary study". Arch Gynecol Obstet. 289 (5): 1129–34. doi:10.1007/s00404-013-3102-7. PMC 3984420. PMID 24318169.
- ↑ Povlsen K, Bjørnelius E, Lidbrink P, Lind I (2002). "Relationship of Ureaplasma urealyticum biovar 2 to nongonococcal urethritis". Eur J Clin Microbiol Infect Dis. 21 (2): 97–101. PMID 11939406.
- ↑ Maeda S, Deguchi T, Ishiko H, Matsumoto T, Naito S, Kumon H; et al. (2004). "Detection of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum (biovar 1) and Ureaplasma urealyticum (biovar 2) in patients with non-gonococcal urethritis using polymerase chain reaction-microtiter plate hybridization". Int J Urol. 11 (9): 750–4. doi:10.1111/j.1442-2042.2004.00887.x. PMID 15379939.
- ↑ Couldwell DL, Gidding HF, Freedman EV, McKechnie ML, Biggs K, Sintchenko V; et al. (2010). "Ureaplasma urealyticum is significantly associated with non-gonococcal urethritis in heterosexual Sydney men". Int J STD AIDS. 21 (5): 337–41. doi:10.1258/ijsa.2009.009499. PMID 20498103.