Original Research Obstetrics| Volume 220, ISSUE 6, P594.e1-594.e9, June 2019

Vaginal Ureaplasma parvum serovars and spontaneous preterm birth

Published:February 05, 2019DOI:


      Ureaplasma species (spp) are the bacteria most often isolated from the amniotic cavity of women with preterm labor or preterm premature rupture of membranes; thus, the link between intrauterine Ureaplasma spp infection and adverse pregnancy outcome clearly is established. However, because vaginal Ureaplasma spp colonization is very common in pregnant women, the reason that these microorganisms cause ascending infections in some cases but remain asymptomatic in most pregnancies is not clear. Previous studies suggested an association between vaginal colonization with Ureaplasma parvum as opposed to U urealyticum and preterm delivery. However, because of the high frequency of vaginal Ureaplasma spp colonization during pregnancy, additional risk factors are needed to select a group of women who might benefit from treatment.


      To further identify pregnant women who are at increased risk for preterm delivery, the aim of the present study was to investigate U parvum serovar–specific pathogenicity in a large clinical cohort.

      Study Design

      We serotyped 1316 samples that were positive for U parvum using a high-resolution melt polymerase chain reaction assay, and results were correlated with pregnancy outcome.


      Within U parvum positive samples, serovar 3 was the most common isolate (43.3%), followed by serovar 6 (31.4%) and serovar 1 (25.2%). There was a significantly increased risk for spontaneous preterm birth at very low (<32 weeks gestation; P<.005) and extremely low (<28 weeks gestation; P<.005) gestational age in the group with vaginal U parvum serovar 3 colonization compared with the control group of pregnant women who tested negative for vaginal Ureaplasma spp colonization. This association was found for neither serovar 1 nor serovar 6. The combination of vaginal U parvum serovar 3 colonization and diagnosis of bacterial vaginosis in early pregnancy or a history of preterm birth further increased the risk for adverse pregnancy outcome.


      Colonization with U parvum serovar 3, but not serovar 1 or serovar 6, in early pregnancy is associated with preterm delivery at very and extremely low gestational age. The combination of U parvum serovar 3 colonization and a history of preterm birth or bacterial vaginosis further increases the risk for spontaneous preterm birth at low gestational age and may define a target group for therapeutic intervention studies.

      Key words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Digiulio D.B.
        • Romero R.
        • Kusanovic J.P.
        • et al.
        Prevalence and diversity of microbes in the amniotic fluid, the fetal inflammatory response, and pregnancy outcome in women with preterm pre-labor rupture of membranes.
        Am J Reprod Immunol. 2010; 64: 38-57
        • Sweeney E.L.
        • Kallapur S.G.
        • Gisslen T.
        • et al.
        Placental infection with Ureaplasma species is associated with histologic chorioamnionitis and adverse outcomes in moderately preterm and late-preterm infants.
        J Infect Dis. 2016; 213: 1340-1347
        • Romero R.
        • Miranda J.
        • Kusanovic J.P.
        • et al.
        Clinical chorioamnionitis at term: I, microbiology of the amniotic cavity using cultivation and molecular techniques.
        J Perinat Med. 2015; 43: 19-36
        • Oh K.J.
        • Lee S.E.
        • Jung H.
        • Kim G.
        • Romero R.
        • Yoon B.H.
        Detection of ureaplasmas by the polymerase chain reaction in the amniotic fluid of patients with cervical insufficiency.
        J Perinat Med. 2010; 38: 261-268
        • Yoon B.H.
        • Romero R.
        • Kim M.
        • et al.
        Clinical implications of detection of Ureaplasma urealyticum in the amniotic cavity with the polymerase chain reaction.
        Am J Obstet Gynecol. 2000; 183: 1130-1137
        • Yoon B.H.
        • Romero R.
        • Lim J.H.
        • et al.
        The clinical significance of detecting Ureaplasma urealyticum by the polymerase chain reaction in the amniotic fluid of patients with preterm labor.
        Am J Obstet Gynecol. 2003; 189: 919-924
        • Yoon B.H.
        • Romero R.
        • Park J.S.
        • et al.
        Microbial invasion of the amniotic cavity with Ureaplasma urealyticum is associated with a robust host response in fetal, amniotic, and maternal compartments.
        Am J Obstet Gynecol. 1998; 179: 1254-1260
        • Goldenberg R.L.
        • Andrews W.W.
        • Goepfert A.R.
        • et al.
        The Alabama Preterm Birth Study: umbilical cord blood Ureaplasma urealyticum and Mycoplasma hominis cultures in very preterm newborn infants.
        Am J Obstet Gynecol. 2008; 198: 43.e1-43.e5
        • Breugelmans M.
        • Vancutsem E.
        • Naessens A.
        • Laubach M.
        • Foulon W.
        Association of abnormal vaginal flora and Ureaplasma species as risk factors for preterm birth: a cohort study.
        Acta Obstet Gynecol Scand. 2010; 89: 256-260
        • Vogel I.
        • Thorsen P.
        • Hogan V.K.
        • Schieve L.A.
        • Jacobsson B.
        • Ferre C.D.
        The joint effect of vaginal Ureaplasma urealyticum and bacterial vaginosis on adverse pregnancy outcomes.
        Acta Obstet Gynecol Scand. 2006; 85: 778-785
        • Rittenschober-Bohm J.
        • Waldhoer T.
        • Schulz S.M.
        • et al.
        First trimester vaginal ureaplasma biovar colonization and preterm birth: results of a prospective multicenter study.
        Neonatology. 2017; 113: 1-6
        • Robertson J.A.
        • Stemke G.W.
        • Davis Jr., J.W.
        • et al.
        Proposal of Ureaplasma parvum sp. nov. and emended description of Ureaplasma urealyticum (Shepard et al. 1974) Robertson et al. 2001.
        Int J Syst Evol Microbiol. 2002; 52: 587-597
        • Kim M.
        • Kim G.
        • Romero R.
        • Shim S.S.
        • Kim E.C.
        • Yoon B.H.
        Biovar diversity of Ureaplasma urealyticum in amniotic fluid: distribution, intrauterine inflammatory response and pregnancy outcomes.
        J Perinat Med. 2003; 31: 146-152
        • Abele-Horn M.
        • Wolff C.
        • Dressel P.
        • Pfaff F.
        • Zimmermann A.
        Association of Ureaplasma urealyticum biovars with clinical outcome for neonates, obstetric patients, and gynecological patients with pelvic inflammatory disease.
        J Clin Microbiol. 1997; 35: 1199-1202
        • Kataoka S.
        • Yamada T.
        • Chou K.
        • et al.
        Association between preterm birth and vaginal colonization by mycoplasmas in early pregnancy.
        J Clin Microbiol. 2006; 44: 51-55
        • Xiao L.
        • Glass J.I.
        • Paralanov V.
        • et al.
        Detection and characterization of human Ureaplasma species and serovars by real-time PCR.
        J Clin Microbiol. 2010; 48: 2715-2723
        • Payne M.S.
        • Ireland D.J.
        • Watts R.
        • et al.
        Ureaplasma parvum genotype, combined vaginal colonisation with Candida albicans, and spontaneous preterm birth in an Australian cohort of pregnant women.
        BMC Pregnancy Childbirth. 2016; 16: 312
        • Martinez M.A.
        • Ovalle A.
        • Santa-Cruz A.
        • Barrera B.
        • Vidal R.
        • Aguirre R.
        Occurrence and antimicrobial susceptibility of Ureaplasma parvum (Ureaplasma urealyticum biovar 1) and Ureaplasma urealyticum (Ureaplasma urealyticum biovar 2) from patients with adverse pregnancy outcomes and normal pregnant women.
        Scand J Infect Dis. 2001; 33: 604-610
        • Paralanov V.
        • Lu J.
        • Duffy L.B.
        • et al.
        Comparative genome analysis of 19 Ureaplasma urealyticum and Ureaplasma parvum strains.
        BMC Microbiol. 2012; 12: 88
        • De Francesco M.A.
        • Negrini R.
        • Pinsi G.
        • Peroni L.
        • Manca N.
        Detection of Ureaplasma biovars and polymerase chain reaction-based subtyping of Ureaplasma parvum in women with or without symptoms of genital infections.
        Eur J Clin Microbiol Infect Dis. 2009; 28: 641-646
        • Xiao L.
        • Paralanov V.
        • Glass J.I.
        • et al.
        Extensive horizontal gene transfer in ureaplasmas from humans questions the utility of serotyping for diagnostic purposes.
        J Clin Microbiol. 2011; 49: 2818-2826
        • Ireland D.J.
        • Keelan J.A.
        The maternal serological response to intrauterine ureaplasma sp. infection and prediction of risk of pre-term birth.
        Front Immunol. 2014; 5: 624
        • Payne M.S.
        • Tabone T.
        • Kemp M.W.
        • Keelan J.A.
        • Spiller O.B.
        • Newnham J.P.
        High-resolution melt PCR analysis for genotyping of Ureaplasma parvum isolates directly from clinical samples.
        J Clin Microbiol. 2014; 52: 599-606
        • Nugent R.P.
        • Krohn M.A.
        • Hillier S.L.
        Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation.
        J Clin Microbiol. 1991; 29: 297-301
        • Stephens A.S.
        • Lain S.J.
        • Roberts C.L.
        • Bowen J.R.
        • Nassar N.
        Survival, hospitalization, and acute-care costs of very and moderate preterm infants in the first 6 years of life: a population-based study.
        J Pediatr. 2016; 169: 61-68.e3
        • Morency A.M.
        • Bujold E.
        The effect of second-trimester antibiotic therapy on the rate of preterm birth.
        J Obstet Gynaecol Can. 2007; 29: 35-44
        • Eschenbach D.A.
        • Nugent R.P.
        • Rao A.V.
        • et al.
        A randomized placebo-controlled trial of erythromycin for the treatment of Ureaplasma urealyticum to prevent premature delivery: The Vaginal Infections and Prematurity Study Group.
        Am J Obstet Gynecol. 1991; 164: 734-742
        • Naessens A.
        • Foulon W.
        • Breynaert J.
        • Lauwers S.
        Serotypes of Ureaplasma urealyticum isolated from normal pregnant women and patients with pregnancy complications.
        J Clin Microbiol. 1988; 26: 319-322
        • Dando S.J.
        • Nitsos I.
        • Kallapur S.G.
        • et al.
        The role of the multiple banded antigen of Ureaplasma parvum in intra-amniotic infection: major virulence factor or decoy?.
        PLoS One. 2012; 7: e29856
        • Knox C.L.
        • Dando S.J.
        • Nitsos I.
        • et al.
        The severity of chorioamnionitis in pregnant sheep is associated with in vivo variation of the surface-exposed multiple-banded antigen/gene of Ureaplasma parvum.
        Biol Reprod. 2010; 83: 415-426
        • Sweeney E.L.
        • Kallapur S.G.
        • Meawad S.
        • et al.
        Ureaplasma species multiple banded antigen (MBA) variation is associated with the severity of inflammation in vivo and in vitro in human placentae.
        Front Cell Infect Microbiol. 2017; 7: 123
        • Digiulio D.B.
        • Callahan B.J.
        • McMurdie P.J.
        • et al.
        Temporal and spatial variation of the human microbiota during pregnancy.
        Proc Natl Acad Sci U S A. 2015; 112: 11060-11065
        • Hyman R.W.
        • Fukushima M.
        • Jiang H.
        • et al.
        Diversity of the vaginal microbiome correlates with preterm birth.
        Reprod Sci. 2014; 21: 32-40
        • Romero R.
        • Hassan S.S.
        • Gajer P.
        • et al.
        The vaginal microbiota of pregnant women who subsequently have spontaneous preterm labor and delivery and those with a normal delivery at term.
        Microbiome. 2014; 2: 1-15
        • Romero R.
        • Hassan S.S.
        • Gajer P.
        • et al.
        The composition and stability of the vaginal microbiota of normal pregnant women is different from that of non-pregnant women.
        Microbiome. 2014; 2: 4
        • Harada K.
        • Tanaka H.
        • Komori S.
        • et al.
        Vaginal infection with Ureaplasma urealyticum accounts for preterm delivery via induction of inflammatory responses.
        Microbiol Immunol. 2008; 52: 297-304
        • Donders G.G.
        • Ruban K.
        • Bellen G.
        • Petricevic L.
        Mycoplasma/Ureaplasma infection in pregnancy: to screen or not to screen.
        J Perinat Med. 2017; 45: 505-515
        • Foschi C.
        • Salvo M.
        • D’Antuono A.
        • et al.
        Distribution of genital Mollicutes in the vaginal ecosystem of women with different clinical conditions.
        New Microbiol. 2018; 41: 225-229
        • Gomez R.
        • Romero R.
        • Nien J.K.
        • et al.
        Antibiotic administration to patients with preterm premature rupture of membranes does not eradicate intra-amniotic infection.
        J Matern Fetal Neonatal Med. 2007; 20: 167-173
        • Antsaklis A.
        • Daskalakis G.
        • Michalas S.
        • Aravantinos D.
        Erythromycin treatment for subclinical Ureaplasma urealyticum infection in preterm labor.
        Fetal Diagn Ther. 1997; 12: 89-92
        • Vouga M.
        • Greub G.
        • Prod’hom G.
        • et al.
        Treatment of genital mycoplasma in colonized pregnant women in late pregnancy is associated with a lower rate of premature labour and neonatal complications.
        Clin Microbiol Infect. 2014; 20: 1074-1079
        • Dando S.J.
        • Nitsos I.
        • Newnham J.P.
        • Jobe A.H.
        • Moss T.J.
        • Knox C.L.
        Maternal administration of erythromycin fails to eradicate intrauterine ureaplasma infection in an ovine model.
        Biol Reprod. 2010; 83: 616-622
        • Witt A.
        • Sommer E.M.
        • Cichna M.
        • et al.
        Placental passage of clarithromycin surpasses other macrolide antibiotics.
        Am J Obstet Gynecol. 2003; 188: 816-819
        • Acosta E.P.
        • Grigsby P.L.
        • Larson K.B.
        • et al.
        Transplacental transfer of Azithromycin and its use for eradicating intra-amniotic ureaplasma infection in a primate model.
        J Infect Dis. 2014; 209: 898-904
        • Keelan J.A.
        • Kemp M.W.
        • Payne M.S.
        • et al.
        Maternal administration of solithromycin, a new, potent, broad-spectrum fluoroketolide antibiotic, achieves fetal and intra-amniotic antimicrobial protection in a pregnant sheep model.
        Antimicrob Agents Chemother. 2014; 58: 447-454
        • Miura Y.
        • Payne M.S.
        • Keelan J.A.
        • et al.
        Maternal intravenous treatment with either azithromycin or solithromycin clears Ureaplasma parvum from the amniotic fluid in an ovine model of intrauterine infection.
        Antimicrob Agents Chemother. 2014; 58: 5413-5420
        • Payne M.S.
        • Furfaro L.L.
        • Tucker R.
        • Tan L.Y.
        • Mokany E.
        One-step simultaneous detection of Ureaplasma parvum and genotypes SV1, SV3 and SV6 from clinical samples using PlexPCR technology.
        Lett Appl Microbiol. 2017; 65: 153-158
        • Sung T.J.
        • Xiao L.
        • Duffy L.
        • Waites K.B.
        • Chesko K.L.
        • Viscardi R.M.
        Frequency of ureaplasma serovars in respiratory secretions of preterm infants at risk for bronchopulmonary dysplasia.
        Pediatr Infect Dis J. 2011; 30: 379-383
        • Kasper D.C.
        • Mechtler T.P.
        • Reischer G.H.
        • et al.
        The bacterial load of Ureaplasma parvum in amniotic fluid is correlated with an increased intrauterine inflammatory response.
        Diagn Microbiol Infect Dis. 2010; 67: 117-121
        • Aaltonen R.
        • Heikkinen J.
        • Vahlberg T.
        • Jensen J.S.
        • Alanen A.
        Local inflammatory response in choriodecidua induced by Ureaplasma urealyticum.
        BJOG. 2007; 114: 1432-1435
        • Kiss H.
        • Petricevic L.
        • Husslein P.
        Prospective randomised controlled trial of an infection screening programme to reduce the rate of preterm delivery.
        BMJ. 2004; 329: 371
        • Kekki M.
        • Kurki T.
        • Pelkonen J.
        • Kurkinen-Raty M.
        • Cacciatore B.
        • Paavonen J.
        Vaginal clindamycin in preventing preterm birth and peripartal infections in asymptomatic women with bacterial vaginosis: a randomized, controlled trial.
        Obstet Gynecol. 2001; 97: 643-648
        • Subtil D.
        • Brabant G.
        • Tilloy E.
        • et al.
        Early clindamycin for bacterial vaginosis in pregnancy (PREMEVA): a multicentre, double-blind, randomised controlled trial.
        Lancet. 2018; 392: 2171-2179
        • Ugwumadu A.
        • Manyonda I.
        • Reid F.
        • Hay P.
        Effect of early oral clindamycin on late miscarriage and preterm delivery in asymptomatic women with abnormal vaginal flora and bacterial vaginosis: a randomised controlled trial.
        Lancet. 2003; 361: 983-988