Serotypes of Ureaplasma urealyticum isolated from normal pregnant women and patients with pregnancy complications

Ability of Ureaplasma parvum to invade mouse sperm, fertilize eggs through infected sperm, and impair mouse sperm function and embryo development

OBJECTIVE

To examine the effect of Ureaplasma parvum (U. parvum) infection on mouse sperm motility, structure, and fertilizing ability and on embryo development.

DESIGN

In vitro model of the effects of U. parvum serovar 3 infection on mouse sperm.

SETTING

Basic research laboratory.

INTERVENTION(S)

None.

ANIMALS

Mice.

MAIN OUTCOME MEASURE(S)

Mouse sperm motility was examined using the swim-up method, and their motility parameters were analyzed using the sperm motility analysis system. Localization and invasion of U. parvum were observed with fluorescence, confocal, and scanning electron microscopy. After in vitro fertilization with U. parvum-infected sperm, the quality of the fertilized egg and embryo development were assessed.

RESULT(S)

U. parvum was attached and internalized into mouse sperms and localized mainly at the sperm head and midpiece. U. parvum-infected mouse sperms exhibited decreased motility in a dose- and duration-dependent manner. Electron micrographs revealed that U. parvum infection induced the aggregation and morphological destruction of mouse sperm. Infected mouse sperm transported U. parvum into the fertilized egg with reduced fertilization rates, and infected embryo development was impaired.

CONCLUSION(S)

U. parvum infection caused deterioration of the mouse sperm quality and its functions, which affected the fertilization rate and embryo development.

Detection of Ureaplasma Biovars and Subtyping of Ureaplasma parvum among Women Referring to a University Hospital in Morocco

Objectives

The aim of this study was to determine the prevalence of Ureaplasma biovars and Ureaplasma parvum (U. parvum) serovars, their associated risk factors, and genital STI-related symptoms.

Methods

DNA obtained from cervical samples of 1053 women attending the department of Obstetrics and Gynecology and the laboratory of pathological anatomy of Hassan II university hospital of Fez, Morocco, was used to detect Ureaplasma biovars (U. urealyticum and U. parvum) and to subtype U. parvum by polymerase chain reaction (PCR).

Results

Of the 1053 women examined, 25.4% (268/1053) were Ureaplasma positives. The rates of U. urealyticum and U. parvum were 12.1% (128/1053) and 7% (74/1053), respectively, and the copresence of these biovars was noted in 6.3% (66/1053) cases. The U. parvum subtyping revealed a predominance of the serovar 3/14 (61.4%). The association of demographics variables with Ureaplasma biovars was studied and shows that the age (“<30” years) seems to be a risk factor of Ureaplasma spp. and U. urealyticum carriage (OR 1.729, 95% CI [1.113-2.687] and OR 1.848, 95% CI [1.026-3.330], respectively). There was no difference in the prevalence of Ureaplasma type regarding symptoms. However, a significant association was found between U. parvum serovar 1 and infertility (P = 0.011).

Conclusion

This first study conducted in Morocco provides an idea on Ureaplasma biovars and U. parvum serovars circulating in this region, their associated risk factors, and genital STI-related symptoms. Therefore, further studies are required to clarify and confirm the pathogenic role of these Ureaplasma species.

Vaginal Ureaplasma parvum serovars and spontaneous preterm birth

BACKGROUND

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.

OBJECTIVE

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.

RESULTS

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.

CONCLUSION

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.

Ureaplasma Species Multiple Banded Antigen (MBA) Variation Is Associated with the Severity of Inflammation In vivo and In vitro in Human Placentae

Background: The multiple banded antigen (MBA), a surface-exposed lipoprotein, is a proposed virulence factor of Ureaplasma spp. We previously demonstrated that the number of Ureaplasma parvum MBA size variants in amniotic fluid was inversely proportional to the severity of chorioamnionitis in experimentally infected pregnant sheep. However, the effect of ureaplasma MBA size variation on inflammation in human pregnancies has not been reported.

Methods: Ureaplasmas isolated from the chorioamnion of pregnant women from a previous study (n = 42) were speciated/serotyped and MBA size variation was demonstrated by PCR and western blot. Results were correlated with the severity of chorioamnionitis and cord blood cytokines. In vitro, THP-1-derived macrophages were exposed to recombinant-MBA proteins of differing sizes and NF-κB activation and cytokine responses were determined.

Results: MBA size variation was identified in 21/32 (65.6%) clinical isolates (in 10 clinical isolates MBA size variation was unable to be determined). Any size variation (increase/decrease) of the MBA (regardless of Ureaplasma species or serovar) was associated with mild or absent chorioamnionitis (P = 0.023) and lower concentrations of cord blood cytokines IL-8 (P = 0.04) and G-CSF (P = 0.008). In vitro, recombinant-MBA variants elicited different cytokine responses and altered expression of NF-κB p65.

Conclusion: This study demonstrates that size variation of the ureaplasma MBA protein modulates the host immune response in vivo and in vitro.

The Human Ureaplasma Species as Causative Agents of Chorioamnionitis

The human Ureaplasma species are the most frequently isolated microorganisms from the amniotic fluid and placentae of women who deliver preterm and are also associated with spontaneous abortions or miscarriages, neonatal respiratory diseases, and chorioamnionitis. Despite the fact that these microorganisms have been habitually found within placentae of pregnancies with chorioamnionitis, the role of Ureaplasma species as a causative agent has not been satisfactorily explained. There is also controversy surrounding their role in disease, particularly as not all women infected with Ureaplasma spp. develop chorioamnionitis. In this review, we provide evidence that Ureaplasma spp. are associated with diseases of pregnancy and discuss recent findings which demonstrate that Ureaplasma spp. are associated with chorioamnionitis, regardless of gestational age at the time of delivery. Here, we also discuss the proposed major virulence factors of Ureaplasma spp., with a focus on the multiple-banded antigen (MBA), which may facilitate modulation/alteration of the host immune response and potentially explain why only subpopulations of infected women experience adverse pregnancy outcomes. The information presented within this review confirms that Ureaplasma spp. are not simply "innocent bystanders" in disease and highlights that these microorganisms are an often underestimated pathogen of pregnancy.

The Maternal Serological Response to Intrauterine Ureaplasma sp. Infection and Prediction of Risk of Pre-Term Birth

Pre-term birth (PTB) associated with intrauterine infection and inflammation (IUI) is the major cause of early PTB less than 32 weeks of gestation. Ureaplasma spp. are common commensals of the urogenital tract in pregnancy and are the most commonly identified microorganisms in amniotic fluid of pre-term pregnancies. While we have an understanding of the causal relationship between intra-amniotic infection, inflammation and PTB, we are still unable to explain why vaginal Ureaplasma sp. colonization is tolerated in some women but causes PTB in others. It is now known that placental tissues are frequently colonized by bacteria even in apparently healthy pregnancies delivered at term; usually this occurs in the absence of a significant local inflammatory response. It appears, therefore, that the site, nature, and magnitude of the immune response to infiltrating microorganisms are key in determining pregnancy outcome. Some evidence exists that the maternal serological response to Ureaplasma sp. colonization may be predictive of adverse pregnancy outcome, although issues such as the importance of virulence factors (serovars) and the timing, magnitude, and functional consequences of the immune response await clarification. This mini-review discusses the evidence linking the maternal immune response to risk of PTB and the potential applications of maternal serological analysis for predicting obstetric outcome.

Complete Genome Sequence of Ureaplasma parvum Serovar 3 Strain SV3F4, Isolated in Japan

Here, we present the complete genome sequence of Ureaplasma parvum serovar 3, clinical strain SV3F4, isolated from a Japanese patient with a history of an infectious abortion.

Prevalence of sexually transmitted infections among healthy Korean women: implications of multiplex PCR pathogen detection on antibiotic therapy

In this study, we investigated the prevalence of sexually transmitted infections (STIs) using multiplex real-time PCR assay in healthy Korean women. We also evaluated the risk factors of STIs, and compared the various factors between the STI-positive and the STI-negative groups. A total of 799 endocervical swab samples from healthy Korean women who visited our hospital for general medical check-ups during January 2012 to October 2012 were included. Eight STIs including Human papillomavirus (HPV), Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), Mycoplasma hominis (MH), Ureaplasma urealyticum (UU), Ureaplasma parvum (UP), and Trichomonas vaginalis (TV) were detected using Anyplex II STI-7 Detection assay Detection (Seegene, Seoul, Korea) and Hybrid Capture 2 High-Risk HPV DNA test (Digene Corporation, Gaithersburg, MD, USA) according manufacture's protocols. Ninety-seven (12.1%) subjects were positive for HPV. Of 393 (49.2%) subjects were infected with at least one microorganism and a total of 499 STIs were identified. Among the 393 STI-positive subjects, the proportion of single, double and triple infection was 76.3%, 20.4% and 3.3%, respectively. The median age of the STI-positive group (47 years, range 42-52) was younger than the STI-negative group (49 years, range 43-56; P < 0.001). The infection rate of HPV was significantly higher in the STI-positive group (15.8%, 62/393) than the STI-negative group (8.6%, 35/406) (P = 0.002).

Serological investigation of Ureaplasma urealyticum in Korean preterm infants

Purpose

Ureaplasma colonization is related with perinatal complications in preterm infants. Little is known about the difference in virulence among various Ureaplasma urealyticum serovars. The aim of this study was to determine U. urealyticum serovars of preterm infants in order to assess whether any of the serovars were associated with bronchopulmonary dysplasia (BPD).

Methods

Three hundred forty-four preterm infants with a gestational age less than 34 weeks admitted to Gangnam Severance Hospital neonatal intensive care unit from July 2011 to December 2012 were included in this study. Tracheal and gastric aspirations were conducted on infants to confirm Ureaplasma colonization. Ureaplasma colonization was confirmed in 9% of infants, of these, serovars were determined by real-time polymerase chain reaction.

Results

A total of 31 infants (gestational age, 29.3±3.1 weeks; birth weight, 1,170±790 g) were U. urealyticum positive. The Ureaplasma positive group treated for more days with oxygen and ventilation than the negative group (P<0.05). Histologic chorioamnionitis and moderate to severe BPD were more frequent in the Ureaplasma positive group than in the negative group (P<0.05). U. urealyticum isolates were either found to be a mixture of multiple serovars (32%), serovar 9 alone or combined with other serovars (39%), serovar 11 (26%), 2 (13%), 8 (10%), 10 (13%), and 13 (25%). No individual serovars were significantly associated with moderate to severe BPD and chorioamnionitis.

Conclusion

This is the first study to describe the distribution of U. urealyticum serovars from Korean preterm infants. Ureaplasma-colonized infants showed higher incidence of BPD and chorioamnionitis.

Role of biofilm formation in Ureaplasma antibiotic susceptibility and development of bronchopulmonary dysplasia in preterm neonates

BACKGROUND

Ureaplasma respiratory tract colonization is a risk factor for bronchopulmonary dysplasia (BPD) in preterm infants, but whether Ureaplasma isolates from colonized infants can form biofilms is unknown. We hypothesized that Ureaplasma isolates vary in capacity to form biofilms that contribute to their antibiotic resistance and ability to evade host immune responses. Study objectives were to (1) determine the ability of Ureaplasma isolates from preterm neonates to form biofilms in vitro; (2) compare the susceptibility of the sessile and planktonic organisms to azithromycin (AZI) and erythromycin; and (3) determine the relationship of biofilm-forming capacity in Ureaplasma isolates and the risk for BPD.

METHODS

Forty-three clinical isolates from preterm neonates and 5 American Tissue Culture Collection strains were characterized for their capacity to form biofilms in vitro, and antibiotic susceptibility was performed on each isolate prebiofilm and postbiofilm formation.

RESULTS

Forty-one (95%) clinical and 4 of 5 (80%) American Tissue Culture Collection isolates formed biofilms. All isolates were more susceptible to AZI (minimum inhibitory concentration, MIC50 2 µg/mL) than erythromycin (MIC50 4 µg/mL), and biofilm formation did not significantly affect antibiotic susceptibility for the 2 tested antibiotics. The MIC50 and minimum biofilm inhibitory concentrations (MBIC50) for Ureaplasma urealyticum clinical isolates for AZI were higher than for MIC50 and MBIC50 for Ureaplasma parvum isolates. There were no differences in MIC or MBICs among isolates from BPD infants and non-BPD infants.

CONCLUSIONS

Capacity to form biofilms is common among Ureaplasma spp. isolates, but biofilm formation did not impact MICs for AZI or erythromycin.

Pathogenicity of Ureaplasma urealyticum and Ureaplasma parvum in the lower genital tract of female BALB/c mice

The aim of this study was to establish a murine model of lower genital tract infection by Ureaplasma urealyticum and Ureaplasma parvum and evaluate differences in pathogenicity of five serotypes. BALB/c female mice were divided into seven groups (five mice in each group), including five groups infected in the lower genital tract after treatment with estradiol with U. urealyticum serotypes 4 and 8 and U. parvum serotypes 1, 3, and 6, respectively, and two control groups of untreated mice and estradiol treated mice. The presence of infection was determined on solid and liquid culture media. Tumor necrosis factor-alpha (TNF-α) expression in lower genital tract secretions was determined by PCR, and morphological and histological changes of the lower genital tract were observed. The genital secretions of all inoculated mice were positive for U. urealyticum and U. parvum on culture in both liquid and solid media. TNF-α expression at 7 and 14 days after infection was markedly increased as compared with that of the controls. Morphological changes of the external genitalia included hair loss and erosions, and histological examination revealed infiltration by inflammatory cells. The five serotypes tested were all found to be pathogenic, and the pathogenicity varied with serotype 4 showing the greatest pathogenicity.

Modified real-time PCR for detecting, differentiating, and quantifying Ureaplasma urealyticum and Ureaplasma parvum

We evaluated a previously described quantitative real-time PCR (qPCR) for quantifying and differentiating Ureaplasma parvum and U. urealyticum. Because of nonspecific reactions with Staphylococcus aureus DNA in the U. parvum PCR, we developed a modified qPCR and designed new primers. These oligonucleotides eradicated cross-reactions, indicating higher specificity. The detection limits of the qPCR were determined at 1 and 3 colony-forming units/ml for U. parvum and U. urealyticum, respectively. The quantification limits of the assay for both Ureaplasma species ranged from 2.10(6) to 2.10(1) copy numbers per PCR. A total of 300 patient samples obtained from the lower genital tract were tested with this newly designed qPCR assay and compared with culture results. Of the samples, 132 (44.0%) were culture positive, whereas 151 (50.3%) tested positive using qPCR. The U. parvum and U. urealyticum species were present in 79.5% and 12.6% of the qPCR-positive samples, respectively. Both species were found in 7.9% of those samples. Quantification of U. parvum and U. urealyticum in the samples ranged from less than 2.5 × 10(3) to 7.4 × 10(7) copies per specimen. In conclusion, the modified qPCR is a suitable method for rapid detection, differentiation, and quantification of U. parvum and U. urealyticum.

Extensive horizontal gene transfer in ureaplasmas from humans questions the utility of serotyping for diagnostic purposes

Ureaplasma parvum and Ureaplasma urealyticum are sexually transmitted, opportunistic pathogens of the human urogenital tract. There are 14 known serovars distributed between the two species. For decades, it has been postulated based upon limited data that virulence is related to serotype specificity. The results were often inconclusive due to the small sample size and extensive cross-reactivity between certain serovars. We developed real-time quantitative PCRs that allow reliable differentiation of the two species and type strains of each of the 14 serovars. To investigate species and serovar distributions, we typed 1,061 clinical isolates of human ureaplasmas from diverse patient populations. There was only a tenuous association between individual Ureaplasma serovars and certain patient populations. This may in part be explained by the fact that almost 40% of the isolates were genetic mosaics, apparently arising from the recombination of multiple serovars. This explains the extensive cross-reactivity based upon serotyping and the lack of consistent association of given serotypes with disease.

Frequency of ureaplasma serovars in respiratory secretions of preterm infants at risk for bronchopulmonary dysplasia

OBJECTIVE

Ureaplasma respiratory tract colonization is associated with bronchopulmonary dysplasia (BPD) in preterm infants. Whether the 4 Ureaplasma parvum and 10 Ureaplasma urealyticum serovars differ in virulence is unknown. This study was conducted to determine the distribution of Ureaplasma serovars in respiratory secretions of a prospective cohort of preterm infants and to assess whether any of the serovars are associated with BPD.

METHODS

Serial endotracheal and/or nasopharyngeal aspirates were obtained for Ureaplasma culture and PCR from 136 infants of gestational age <33 weeks. All positive samples were speciated and serovars were determined by real-time PCR.

RESULTS

A total of 51 (37.5%) infants were Ureaplasma-positive one or more times during the first month of life. Respiratory colonization was inversely related to gestational age. Sixty-five percent of infants <26 weeks compared with 31% infants ≥ 26 weeks were culture or PCR positive. U. parvum was more common (N = 32, 63%) than U. urealyticum (N = 17, 33%); both species were present in 2 samples. Serovars 3 and 6 alone and in combination accounted for 96% U. parvum isolates. U. urealyticum isolates were commonly a mixture of multiple serovars, with serovar 11 alone or combined with other serovars (10/17, 59%) being the most common serovar. No individual species or serovars or serovar mixtures were associated with moderate-to-severe BPD.

CONCLUSIONS

U. parvum serovars 3 and 6 and U. urealyticum serovar 11 were the most common serovars detected in respiratory samples from a prospective cohort of preterm infants.

Chlamydia, Mycoplasma and Ureaplasma infections in infertile couples and effects of these infections on fertility

OBJECTIVE

In our study, we aimed to determine the prevalence of Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum infections among infertile couples and effects of these infections on infertility.

MATERIALS AND METHODS

Prevalence of Chlamydia, Mycoplasma, Ureaplasma antibodies and Chlamydia IgM antibodies and its effect on these agents' sperm parameters, namely, morphology, density, and motility were investigated among a total of 212 patients including fertile and infertile couples. Chlamydia, Mycoplasma, Ureaplasma antigens were evaluated using ELISA in the cervical and urethral samples. Chlamydia IgM antibody was measured using micro-ELISA in blood samples.

RESULTS

No difference was detected among the fertile and infertile groups in the serological investigation of urethral and cervical samples with respect to the prevalence of Chlamydia, Mycoplasma, Ureaplasma antigens and Chlamydia IgM antibody and sperm parameters (p > 0.05).

DISCUSSION

There is no significant difference between fertile and infertile couples in terms of the prevalence of the above mentioned infections. Accordingly, during the infertility assessment, infertile couples should not be routinely screened for these infective agents without any clinically sound evidence.

The severity of chorioamnionitis in pregnant sheep is associated with in vivo variation of the surface-exposed multiple-banded antigen/gene of Ureaplasma parvum

Ureaplasma species are the bacteria most frequently isolated from human amniotic fluid in asymptomatic pregnancies and placental infections. Ureaplasma parvum serovars 3 and 6 are the most prevalent serovars isolated from men and women. We hypothesized that the effects on the fetus and chorioamnion of chronic ureaplasma infection in amniotic fluid are dependent on the serovar, dose, and variation of the ureaplasma multiple-banded antigen (MBA) and mba gene. We injected high- or low-dose U. parvum serovar 3, serovar 6, or vehicle intra-amniotically into pregnant ewes at 55 days of gestation (term = 150 days) and examined the chorioamnion, amniotic fluid, and fetal lung tissue of animals delivered by cesarean section at 125 days of gestation. Variation of the multiple banded antigen/mba generated by serovar 3 and serovar 6 ureaplasmas in vivo were compared by PCR assay and Western blot. Ureaplasma inoculums demonstrated only one (serovar 3) or two (serovar 6) MBA variants in vitro, but numerous antigenic variants were generated in vivo: serovar 6 passage 1 amniotic fluid cultures contained more MBA size variants than serovar 3 (P = 0.005), and ureaplasma titers were inversely related to the number of variants (P = 0.025). The severity of chorioamnionitis varied between animals. Low numbers of mba size variants (five or fewer) within amniotic fluid were associated with severe inflammation, whereas the chorioamnion from animals with nine or more mba variants showed little or no inflammation. These differences in chorioamnion inflammation may explain why not all women with in utero Ureaplasma spp. experience adverse pregnancy outcomes.

Production of recombinant antigens of Ureaplasma parvum serotypes 3 and 6 for development of a serological assay

Recombinant antigens of Ureaplasma parvum serotypes 3 and 6 were produced in order to develop a serological assay for Ureaplasma antibody detection. The genes of the multiple banded antigen (MBA) were amplified by PCR and cloned in a pTrcHis TOPO plasmid. Purified recombinant proteins were evaluated in Western blotting and enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies and human sera. Our approach was successful in the production of the recombinant MBAs (rMBAs) for serotypes 3 and 6. The antigens tested positive with serotype-specific monoclonal antibodies in Western blotting and in ELISA. Prominent reactions were detected with the rMBAs and their homologous monoclonal antibodies. Strong cross-reactions were visible in ELISA between rMBA 3 and the monoclonal antibodies from the other U. parvum serotypes. A weak cross-reaction was seen with rMBA 3 and the monoclonal antibody from serotype 4. rMBA 6 showed cross-reaction only with the monoclonal antibody from U. parvum serotype 1. Fifty-one percent of the sera obtained from culture-positive women reacted with one or both rMBAs. Only three (15%) of the sera from culture-negative women reacted with the rMBA. The positive reactions were observed only with rMBA 6. These preliminary tests showed the potential usefulness of the rMBAs produced for detecting an antibody response against Ureaplasma antigens.

Genotypic characterization of Ureaplasma species by pulsed field gel electrophoresis

We describe the first use of pulsed field gel electrophoresis to genotype human Ureaplasma species. This technique can distinguish between U. urealyticum and U. parvum, differentiate most of the 14 serovars from one another, and identify differences among clinical isolates of the same serovar.

Detection and biovar discrimination of Ureaplasma urealyticum by real-time PCR

Prenatal intrauterine infection has been recognized as an important cause of premature birth, and Ureaplasma urealyticum is one of the commonest pathogens. U. urealyticum consists of 14 serovars that can be divided into two biovars (parvo and T960), and the pathogenicity of U. urealyticum may be different according to the biovar. To detect U. urealyticum and determine its biovar simultaneously, we developed a real-time polymerase chain reaction (PCR) assay targeting urease gene. The real-time PCR biovar-typed two reference strains and 42 culture isolates of U. urealyticum as correctly as conventional PCR with direct sequencing. Subsequently, 87 clinical specimens (amniotic fluid, cord blood, vaginal swab) were tested for culture, conventional PCR, and real-time PCR. When compared with conventional PCR, sensitivity and specificity of real-time PCR were 89.5 and 98.5%, respectively, and those of culture were 47.4 and 100%, respectively. Of 18 clinical specimens that were found positive and biovar-typed by real-time PCR, parvo biovar was 66.7% and T960 biovar was 33.3%. This real-time PCR assay can be useful for the simultaneous detection and biovar discrimination of U. urealyticum in clinical specimens. Further study to quantify U. urealyticum would be facilitated on the basis of this method.

Characterization of ureaplasmas isolated from preterm infants with and without bronchopulmonary dysplasia

A PCR assay was used to analyze endotracheal aspirates from preterm infants for Ureaplasma parvum versus U. urealyticum. U. parvum was detected more often than U. urealyticum. There was no significant difference or trend in the prevalence of either species between infants with or without bronchopulmonary dysplasia when isolated alone.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

Experimental intrauterine Ureaplasma infection in sheep

OBJECTIVE

Prenatal Ureaplasma spp exposure is associated with preterm birth and modulates the neonates' susceptibility to respiratory distress syndrome and bronchopulmonary dysplasia. We hypothesized that intra-amniotic ureaplasmas would cause lung inflammation and alter fetal lung development.

STUDY DESIGN

Pregnant ewes bearing singleton fetuses were given an intra-amniotic injection of 20 x 10 6 CFUs of U parvum (serovar 3) or vehicle, either 1, 3, 6, or 10 weeks before the delivery of preterm lambs at 124 days of gestation (n = 4-10 per group) for evaluation of inflammation and fetal lung maturation.

RESULTS

Ureaplasmas were recovered from amniotic and fetal lung fluids after intra-amniotic injection. Body weight and umbilical arterial pH were reduced by Ureaplasma exposure for 10 weeks ( P < .05). Ureaplasmas caused progressive lung inflammation and improvements in lung function that were associated with increased surfactant lipids (control, 0.13 +/- 0.02 micromol/kg; 10 weeks of Ureaplasma exposure, 7.43 +/- 3.0 micromol/kg; P < .001) and surfactant protein messenger RNA expression.

CONCLUSION

Long-term exposure to ureaplasmas in amniotic fluid alters ovine fetal development.

Cervical Ureaplasma urealyticum colonization might be associated with increased incidence of preterm delivery in pregnant women without prophlogistic microorganisms on routine examination

AIM

We examined whether the detection of Ureaplasma urealyticum DNA in the cervix is associated with preterm labor and delivery.

METHODS

Eighty-two women (23 preterm labor cases and 59 controls) with no evidence of prophlogistic microorganisms on routine microbiologic examination were enrolled for this study. U. urealyticum colonization was examined using polymerase chain reaction of cervical swabs.

RESULTS

The positivity rate of U. urealyticum DNA in preterm labor cases was significantly higher than that in the controls (87.0%vs 45.8%, P=0.0007). Women in the U. urealyticum-positive group more frequently delivered preterm compared with those in the negative group (36.2%vs 11.4%, P=0.0111). In five cases that delivered preterm with histologically confirmed chorioamnionitis, U. urealyticum DNA was detected in the placenta.

CONCLUSIONS

Cervical U. urealyticum colonization might be associated with preterm labor and delivery.

[Up to date in sexually transmitted infections: epidemiology, diagnostic approaches and treatments]

In the last years, there have been important advances in sexually transmitted infections such as genome sequencing of Treponema pallidum, Chlamydia trachomatis or Mycoplasma genitalium; the new taxonomic position of Calymmatobacterium granulomatis; commercial diagnostic systems based on nucleic acid amplification; the emergence of quinolone resistance in Neisseria gonorrhoeae; new therapeutic approaches in vulvovaginal candidiasis that include boric acid; the demonstration that valacyclovir reduces the risk of transmission of genital herpes or the availability of immune-response modifier in the treatment of genital warts, and that are questions in the goal of this review. Viral hepatitis and HIV were no reviewed by space reasons.

Comparison of multiplex PCR assay with culture for detection of genital mycoplasmas

Ureaplasma, spp. Mycoplasma genitalium, and Mycoplasma hominis are associated with infection of the genitourinary tract, reproductive failure, and neonatal morbidity and mortality. We have developed a multiplex PCR for the detection of these Mycoplasmatales in a single amplification reaction. The analytical sensitivities of this assay were 10.8, 10.8, and 8.8 CFU for each organism, respectively. This multiplex PCR was compared to culture on 26 cervical swabs, 2 vaginal swabs, 4 female urine specimens, 49 semen samples, 2 male urine specimens, and 1 nonspecified sample. A total of 21 specimens were culture positive (25%); 17 of these were PCR positive. An additional 11 specimens were PCR positive but culture negative. Of the 21 culture-positive specimens, 17 (81%) grew Ureaplasma spp. and 4 (19%) grew Mycoplasma spp. Of the 28 PCR-positive specimens, Ureaplasma spp. was detected in 23 (82%), M. hominis was detected in 3 (11%), and both were detected in 2 (7%). In a confirmatory analysis, all samples were tested by amplification of a second target of the ureaplasma genome. True-positive cases were defined as a positive result by culture or by both amplification assays. The multiplex PCR detected organisms in 26 of the 30 true-positive specimens, as well as in 2 other specimens. Based on a 36% prevalence of infection, the sensitivity, specificity, and positive and negative predictive values of multiplex PCR analyses were 87, 96, 94, and 93%, respectively. Multiplex PCR offers a rapid, sensitive, and easy method to detect genital mycoplasmas.

Biovar diversity of Ureaplasma urealyticum in amniotic fluid: distribution, intrauterine inflammatory response and pregnancy outcomes

OBJECTIVE

The objective of this study was to determine the distribution of two biovars of Ureaplasma urealyticum (parvo and T960) in human amniotic fluid and to examine whether the magnitude of the intrauterine inflammatory response and pregnancy outcomes are different between patients with microbial invasion of the amniotic cavity with "parvo biovar" and those with "T960 biovar".

STUDY DESIGN

This cohort included 77 preterm singleton pregnancies (gestational age < 37 weeks) in whom U. urealyticum was detected from amniotic fluid using the polymerase chain reaction (PCR). Amniotic fluid was obtained by transabdominal amniocentesis. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as mycoplasmas. U. urealyticum was biotyped by PCR methods. Amniotic fluid inflammatory response was determined by amniotic fluid white blood cell count and interleukin-6 concentration.

RESULTS

1) The "parvo biovar" was detected in 82% (63/77) and "T960 biovar" was in 18% (14/77) of cases; 2) U. urealyticum was isolated by conventional culture method from amniotic fluid in 56% (35/63) of cases with positive for "parvo biovar" and in 50% (7/14) of cases with positive for "T960 biovar"; 3) There were no significant differences in the median gestational age at amniocentesis, gestational age at delivery, birth weight, amniotic fluid white blood cell count, amniotic fluid interleukin-6 concentration and the rates of clinical chorioamnionitis, histologic chorioamnionitis, funisitis and neonatal morbidity between patients in the two biovar groups.

CONCLUSIONS

1) The "parvo biovar" is more frequently isolated from amniotic fluid of preterm gestations than the "T960 biovar"; 2) Biovar diversity of U. urealyticum in amniotic fluid was not associated with different pregnancy outcome and magnitude of the intraamniotic inflammatory response.

Comparison of two methods for serotyping Ureaplasma urealyticum clinical isolates

A newly developed enzyme linked immunosorbent assay (ELISA) method using monoclonal antibodies (MAbs) to the 14 serotypes of Ureaplasma urealyticum was compared to immunofluorescence assay (IFA) for serotyping U. urealyticum clinical isolates. Of the 102 vaginal isolates of U. urealyticum, five strains were lost and were excluded from analysis. Of the 97 strains analysed, a total of 86 (89%) strains were typeable by ELISA and a total of 89 (92%) strains were typeable by IFA. Eighty-six strains were typeable by both methods, three by IFA only and eight strains were not typeable neither by ELISA nor by IFA. Of the 86 strains typeable by both methods, complete concordance in serotyping results was found. The three strains not typeable by ELISA were typeable as serotype 4 by IFA. These three strains were reanalysed by ELISA after major modifications of the antigen preparation and were typeable as serotype 4. In conclusion, the ELISA was found suitable for serotyping clinical isolates. However, since the ELISA had a somewhat lower performance than IFA, strains not typeable by ELISA, should be retested by another technique such as IFA.

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

A recent phylogenetic analysis of Ureaplasma urealyticum resulted in the proposal to divide their 2 biovars into species. We used PCR to compare the distribution of species and the presence of the tet(M) and int-Tn resistance determinants in 63 strains of Ureaplasma spp. isolated from the amniotic fluid of patients with an adverse pregnancy outcome and in 22 strains obtained from the lower genital tract of healthy pregnant women. We also determined the antimicrobial susceptibility of the organisms to erythromycin and tetracycline. U. parvum was the most frequent Ureaplasma species detected in our study. Thus, 50/63 (79.4%) invasive isolates and 17/22 (77.3%) lower genital tract isolates corresponded to U. parvum, whereas 12/63 (19%) invasive isolates and 4/22 (18.2%) non-invasive strains corresponded to U. urealyticum. A mixture of species was found in 2 women. We found no significant differences in the antimicrobial susceptibility of isolates according to species or origin of isolation. Sixty-two strains of Ureaplasma spp. (74.7%) were susceptible to erythromycin, and 21 strains (25.3%) were intermediately susceptible. Sixty-eight isolates (81.9%) were susceptible to tetracycline, 2 strains (2.4%) were intermediate and 13 strains (15.7%) were resistant. DNA sequences related to the tet(M) determinant and the int-Tn gene were found in all tetracycline-resistant isolates.

Simple method for determining biovar and serovar types of Ureaplasma urealyticum clinical isolates using PCR-single-strand conformation polymorphism analysis

Ureaplasma urealyticum has been associated with urethritis in men, obstetric problems in women, and respiratory distress syndrome in preterm infants. U. urealyticum can be divided into two biovars comprising 14 serovars. Partial sequences of genes encoding the multiple-banded antigens of the cell surface are known. Using a commercially available precast DNA mutation detection gel system, we have developed a simple and reproducible PCR-single-strand conformation polymorphism analysis method for differentiating the biovars of this species that reveals five patterns among the 14 serovars and enables clinical isolates to be typed directly from broth cultures.

Development of an enzyme-linked immunosorbent assay for serotyping ureaplasma urealyticum strains using monoclonal antibodies

Ureaplasma urealyticum comprises 14 serotypes. The existing serotyping methods all use polyclonal antibodies. These methods are time-consuming and labor-intensive, and they cannot always be performed on primary isolates; in addition, the results are difficult to interpret. We developed a new enzyme-linked immunosorbent assay (ELISA) method using serotype-specific monoclonal antibodies (MAbs) to enable the serotyping of U. urealyticum isolates from primary broth cultures. Each of the 14 serotype reference strains was tested against 14 selected MAbs. Homologous reactions were very strong, while heterologous reactions were negligible. Three cross-reactions were observed: MAb 5 cross-reacted with serotype 2, MAb 14 cross-reacted with serotype 3, and MAb 8 cross-reacted with serotype 13. Despite the cross-reactions observed, all the serotype reference strains of U. urealyticum could be identified and differentiated using a combination of MAbs. Reproducibility was analyzed with a fractionated antigenic preparation and with several freshly prepared antigens of the same strain. No significant interrun variation was found with the fractionated antigen, but significant variations in optical density (OD) values were found when freshly prepared antigens were tested. However, the variation in OD values did not influence the overall interpretation of the ELISA: reactions with homologous MAbs were always prominent compared to those of the negative controls. This newly developed ELISA using MAbs seems promising for serotyping of U. urealyticum clinical isolates.

Ureaplasma urealyticum-induced production of proinflammatory cytokines by macrophages

Ureaplasma urealyticum is relatively common in the respiratory tract of very low birth weight infants and has been hypothesized to be involved in the development of chronic lung disease. The purpose of this study was to investigate whether U. urealyticum could stimulate macrophages to produce proinflammatory cytokines in vitro, which are early pathologic changes in the lung during the development of chronic lung disease. A human monocytic cell line (THP-1) differentiated to macrophages, a rat alveolar macrophage cell line (Nr8383), and human lung macrophages from tracheobronchial aspirate fluid in preterm infants were exposed to U. urealyticum antigen for 24 h. The protein levels of human IL-6, tumor necrosis factor-alpha (TNF-alpha), and rat TNF-alpha were measured with ELISA. Rat IL-6 was analyzed with a specific bioassay. The mRNA levels of these cytokines were detected by reverse transcriptase-PCR. The production of TNF-alpha and IL-6 increased after stimulation with U. urealyticum in both the human and rat macrophage cell lines. In tracheobronchial aspirate fluid macrophages, U. urealyticum increased the production of TNF-alpha from 14 to 84% and IL-6 from 46 to 268% above control levels. U. urealyticum also induced gene expression of TNF-alpha and IL-6. In conclusion, U. urealyticum could be an important factor in the development of chronic lung disease because of its ability to induce alveolar macrophage proinflammatory cytokine production.

Development of monoclonal antibodies against Ureaplasma urealyticum serotypes and their use for serotyping clinical isolates

Monoclonal antibodies (MAbs) against Ureaplasma urealyticum serotype 2, 5, 7, 8, 10, 11, 12, and 13 reference strains were developed. The reactivities of these MAbs with the 14 serotype reference strains was verified by colony immunofluorescence assay and Western blot assay. MAbs against serotypes 2, 7, 10, 11, and 12 were serotype specific, whereas MAbs against serotypes 5, 8, and 13 showed cross-reactivity. All MAbs against serotype 5 were cross-reactive with serotype 2, and one showed, in addition, cross-reactivity to serotypes 9 and 10. Mutual cross-reactivities were observed between MAbs against serotypes 8 and 13. The usefulness of the MAbs for the serotyping of U. urealyticum strains was evaluated by serotyping 21 selected clinical isolates. A complete set of MAbs (the newly developed MAbs and the previously described MAbs against serotypes 1, 3, 4, 6, 9, and 14) as well as a complete set of polyclonal antibodies (PAbs), PAbs 1 to 14, were used. MAbs were able to identify 18 of 21 isolates including 2 isolates with mixed serotypes. Polyreactivity, which occurred with 19 of the 21 isolates with PAbs, was not observed by the use of MAbs. MAbs seem to be a more valuable tool than PAbs for serotyping and could help in investigating a possible link between the expression or variability of the serotype-specific antigens and pathogenicity.

Differentiation of two biovars of Ureaplasma urealyticum based on the 16S-23S rRNA intergenic spacer region

The 16S-23S rRNA intergenic spacer regions of 14 strains representing the 14 serovars of Ureaplasma urealyticum were amplified by PCR and sequenced for genetic differentiation between the two biovars Parvo and T960. Although the spacer region of the Parvo and T960 biovars comprised 302 nucleotides and lacked spacer tRNA genes, 15 nucleotides were different between the two biovars. The four nucleotide sequences of the 16S-23S rRNA intergenic spacer region of serovars 1, 3, 6, and 14 in the Parvo biovar were found to be identical. Similarly, the 10 nucleotide sequences of the 16S-23S rRNA intergenic spacer region of serovars 2, 4, 5, and 7 to 13 in the T960 biovar were found to be identical. The nucleotide sequence of the T960 biovar contains multiple restriction sites for restriction endonuclease SspI, which allows differentiation of the T960 biovar from the Parvo biovar.

Comparative analysis and serovar-specific identification of multiple-banded antigen genes of Ureaplasma urealyticum biovar 1

Ureaplasma urealyticum is a causative agent of nongonococcal urethritis and is implicated in the pathogenesis of several other diseases. The species is divided into 14 serovars and two biovars, of which biovar 1 is most commonly isolated from clinical specimens. Reported associations between individual serovars and diseases have been difficult to confirm because of practical difficulties with serotyping. The multiple-banded antigen (MBA) is the predominant U. urealyticum antigen recognized during infections in humans and probably has a significant role in virulence. The 5' end of the MBA gene is relatively conserved but contains biovar, and possibly serovar, specificity. The 5' ends of the MBA genes of standard strains of U. urealyticum biovar 1, consisting of serovars 1, 3, 6, and 14, were amplified, cloned into pUC19, and sequenced to identify serovar-specific differences. The 5' end of the MBA gene sequence of serovar 3 was identical with the previously published sequence and differed by only three bases from that of serovar 14. Significant differences between the MBA gene sequences allowed biovar 1 to be divided into two subgroups, containing serovars 3/14 and serovars 1 and 6, respectively, using primers UMS-125-UMA269 and UMS-125-UMA269'. Serovars 1 and 6 were distinguished by restriction enzyme analysis of the amplicon and/or by PCR specific for serovar 6. These methods were used to identify and type U. urealyticum in 185 (46.3%) of 400 genital specimens from women. Biovar 1 was detected in 89.2% and biovar 2 in 18.3% of positive specimens. Of 165 specimens containing U. urealyticum biovar 1, 22.2% contained more than one serovar and 46.7, 46.1, and 25.5% contained serovars 1, 3/14, and 6, respectively. U. urealyticum was found in a significantly higher proportion of pregnant women than in sex workers and other women attending a sexually transmissible diseases clinic (P < 0.01). The methods described are relatively rapid, practicable, and specific for serotyping isolates and for direct detection and identification of individual serovars in clinical specimens containing U. urealyticum biovar 1.

Comparison of PCR, nested PCR, and random amplified polymorphic DNA PCR for detection and typing of Ureaplasma urealyticum in specimens from pregnant women

A PCR assay, using three primer pairs, was developed for the detection of Ureaplasma urealyticum, parvo biovar, mba types 1, 3, and 6, in cultured clinical specimens. The primer pairs were designed by using the polymorphic base positions within a 310- to 311-bp fragment of the 5' end and upstream control region of the mba gene. The specificity of the assay was confirmed with reference serovars 1, 3, 6, and 14 and by the amplified-fragment sizes (81 bp for mba 1, 262 bp for mba 3, and 193 bp for mba 6). A more sensitive nested PCR was also developed. This involved a first-step PCR, using the primers UMS-125 and UMA226, followed by the nested mba-type PCR described above. This nested PCR enabled the detection and typing of small numbers of U. urealyticum cells, including mixtures, directly in original clinical specimens. By using random amplified polymorphic DNA (RAPD) PCR with seven arbitrary primers, we were also able to differentiate the two biovars of U. urealyticum and to identify 13 RAPD-PCR subtypes. By applying these subtyping techniques to clinical samples collected from pregnant women, we established that (i) U. urealyticum is often a persistent colonizer of the lower genital tract from early midtrimester until the third trimester of pregnancy, (ii) mba type 6 was isolated significantly more often (P = 0.048) from women who delivered preterm than from women who delivered at term, (iii) no particular ureaplasma subtype(s) was associated with placental infections and/or adverse pregnancy outcomes, and (iv) the ureaplasma subtypes most frequently isolated from women were the same subtypes most often isolated from infected placentas.

Development of a monoclonal antibody to a Ureaplasma urealyticum serotype 9 antigen

We produced a monoclonal antibody (MAb) to Ureaplasma urealyticum Vancouver, the serotype 9 standard strain. By immunoblotting, this MAb showed a single, 85-kDa band with the homologous serotype and a minor, 100-kDa band with serotype 2 but did not react with any other serotype standard strain. Clinical isolates of U. urealyticum were tested with this MAb and with two sets of polyclonal antisera against the 14 serotype standard strains. The use of MAb 9-2H9 correctly identified certain serotype 9 strains but did not react with wild-type strains lacking the serotype 9 determinant.

The correlation of Ureaplasma urealyticum infection with infertility

A prevalence study of Ureaplasma urealyticum (UU) infection of the male genital tract was carried out in Shanghai between March 1992 and June 1995. Significantly higher frequency of UU infection was found among infertile males (549/1416) as compared to fertile controls (34/375). Examination of 8 specimens each from infertile men and fertile subjects by electron microscopy, immunogold and immunofluorescence techniques, demonstrated adhesion of Ureaplasma urealyticum to the membrane of spermatozoa and exfoliated germ cells. In addition, gold particles on Ureaplasma urealyticum were found to be adhered to the sperm surface in 4 of the 8 samples. Strong specific anti-UU fluorescence was detected in 6 of 8 samples, mainly on the midpieces and post-acrosomal regions of the spermatozoa. To further study the effects of Ureaplasma urealyticum on fertility, 47 male Sprague-Dawley (SD) rats were infected artificially with Ureaplasma urealyticum serotype 8 (T960). Morphological changes in the seminiferous tubules were observed 3-5 weeks after inoculation in the sacrificed animals. Dramatic impairment of spermatogenesis of both testes was found in 11 rats. Mating experiment confirmed infertility in 12 of 40 rats. Offsprings of the infected rats were significantly smaller than those of controls in terms of prenatal weights and birthweights.

Clastogenic effects of different Ureaplasma urealyticum serovars on human chromosomes

The possibility that Ureaplasma urealyticum might play an important role in human infertility was first raised more than 20 years ago, but this association remains speculative. Considering the hypothesis that the pathogenicity of Ureaplasma urealyticum may depend on its serotypes, the clastogenic effects of different strains of Ureaplasma urealyticum, at concentrations of 10(3) CCU (color changing units)/ml, 10(4) CCU/ml and 10(5) CCU/ml, were evaluated in vitro in short-term cultures of human lymphocytes. Total or partial mitotic inhibition was produced by Ureaplasma urealyticum serotypes 2, 3 and 10 independent of the concentration (10(3) CCU/ml, 10(4) CCU/ml or 10(5) CCU/ml) of the microorganisms employed. In contrast, the clastogenic effects observed with serotypes 1, 7 and 12 varied according to the concentration employed in the test. Mitotic alterations were observed in Ureaplasma urealyticum serotypes 5, 6, 7, 8, 9, 11 and 12. Chromatid gaps (53.0%) and chromatid breaks (13.9%) were the most frequent types of alterations observed. The results of this in vitro assay demonstrated that the clastogenic effects varied with the Ureaplasma urealyticum serotypes evaluated.

Association of Ureaplasma urealyticum biovars with clinical outcome for neonates, obstetric patients, and gynecological patients with pelvic inflammatory disease

In this prospective study, the prevalence of the two Ureaplasma urealyticum biovars, parvo and T960, was determined in pregnant women and in gynecological patients colonized by ureaplasmas. Furthermore, we investigated the association of these biovars with gynecological complications and adverse pregnancy outcome. Isolates of U. urealyticum from 254 women were biotyped by a PCR method recently developed. The parvo biovar was found in 81% (206 of 254) of the patients, and the T960 biovar was found in 30% (76 of 254) of the patients; 6% (14 of 254) of the women were coinfected. Identical biovars were detected in mothers and their infants. Serial isolations or cultures from different sampling sites of the same individual revealed the same biovar. T960 was dominant in patients with pelvic inflammatory disease (57%) and patients who had had a miscarriage (42%), showed a higher rate of tetracycline resistance than did parvo isolates (55 versus 18%), and seemed to have more adverse effects on pregnancy outcome with regard to birth weight (2,500 versus 1,720 g), gestational age (35 versus 30 weeks), and preterm delivery (35 versus 77%).

Organization of Ureaplasma urealyticum urease gene cluster and expression in a suppressor strain of Escherichia coli

Ureaplasma urealyticum is a pathogenic ureolytic mollicute which colonizes the urogenital tracts of humans. A genetic polymorphism between the two biotypes of U. urealyticum at the level of the urease genes was found. The urease gene cluster from a biotype 1 representative of U. urealyticum (serotype I) was cloned and sequenced. Seven genes were found, with ureA, ureB, and ureC encoding the structural subunits and ureE, ureF, ureG, and a truncated ureI) gene encoding accessory proteins. Urease expression was not obtained when the plasmid containing these genes was incorporated into an opal suppressor strain of Escherichia coli, although this enzymatic activity was found in the same E. coli strain transformed with pC6b, a plasmid with previously cloned urease genes from the U. urealyticum T960 strain of biotype 2 (serotype 8). Although there are 12 TGA triplets encoding tryptophan within urease genes, the level of expression obtained was comparable to the levels reported for other bacterial genes expressed in E. coli. Nested deletion experiments allowed us to demonstrate that ureD is necessary for urease activity whereas another open reading frame located downstream is not. The promoter for ureA and possibly other urease genes was identified for both serotypes.

Identification of serotype 1-, 3-, and 6-specific antigens of Ureaplasma urealyticum by using monoclonal antibodies

Little is known about the antigens responsible for serotype specificity in Ureaplasma urealyticum. We produced monoclonal antibodies to U. urealyticum serotypes 1, 3, and 6, the serotypes most commonly found in pregnant women, and analyzed serotype-specific antigens for the three serotypes. Clinical isolates belonging to serotype 1, 3, or 6 were tested in immunoblots with these monoclonal antibodies. The immunoblot patterns of these isolates were, in most cases, different from each other as well as from those of the reference strains, indicating a high rate of antigenic variation among U. urealyticum strains.

Identification and characterization of serotype 4-specific antigens of Ureaplasma urealyticum by use of monoclonal antibodies

Monoclonal antibodies against Ureaplasma urealyticum serotype 4 were produced by immunizing BALB/c mice with whole-cell antigens of the U. urealyticum serotype 4 reference strain. Ten monoclonal antibodies differentiated into two groups were found: one group included five monoclonal antibodies recognizing a band in immunoblotting that had a molecular mass of 81 kDa, and a second group included another five monoclonal antibodies recognizing three bands in immunoblotting that had molecular masses of 81, 75, and 71 kDa. Fifteen clinical U. urealyticum isolates were selected for serotyping with serotype 4-specific monoclonal antibodies and polyclonal antisera 1 to 14. The results obtained with polyclonal and monoclonal antibodies suggest the existence of heterogeneity of the serotype antigens among clinical isolates of U. urealyticum serotype 4.

Polymerase chain reaction using 16S rRNA gene sequences distinguishes the two biovars of Ureaplasma urealyticum

Several fundamental phenotypic and genotypic differences have separated strains of the genital mycoplasma Ureaplasma urealyticum into two clusters or biovars. However, the lack of an easily performed and unambiguous test to discriminate between them has hampered investigation of the relationship between these biovars and disease. We determined the 16S rRNA nucleotide sequence of U. urealyticum 27, the serovar 3 standard and representative of the parvo biovar (serovars 1, 3, 6, and 14). This sequence was compared with the published sequence of U. urealyticum T960, which is the type strain and the serovar 8 standard and is representative of the T960 biovar which is composed of the 10 intervening serovars. Homology between the two sequences was 98.8%; differences were exploited to provide primers for biovar-specific polymerase chain reactions (PCRs). The results of these reactions placed all 14 serovar standard strains into the correct biovar. The PCRs were also applied to 10 cloned and 8 noncloned isolates that had been serotyped earlier. For 16 of them, we deduced their biovars from the serotyping data and then confirmed them by PCR. One unpredictable isolate and one nonserotypeable isolate were also classified as to biovar. Thus, we have developed a method for biotyping U. urealyticum that is applicable to both laboratory-adapted strains and wild-type isolates and that is appropriate for testing large numbers of clinical isolates. The amplification by the T960 biovar PCR protocol of DNAs from ureaplasmas of animals and certain Mycoplasma species suggested that the parvo biovar has diverged from the mainstream of the evolution of this clade.

Ureaplasma urealyticum intrauterine infection: role in prematurity and disease in newborns

Ureaplasma urealyticum, a common commensal of the urogenital tract of sexually mature humans, is gaining recognition as an important opportunistic pathogen during pregnancy. While its etiologic significance in many aspects of adverse pregnancy remains controversial, recent evidence indicates that U. urealyticum in the absence of other organisms is a cause of chorioamnionitis. Furthermore, ureaplasmal infection of the chorioamnion is significantly associated with premature spontaneous labor and delivery. In at least some cases, it appears to be causal. Present evidence indicates that U. urealyticum is a cause of septicemia, meningitis, and pneumonia in newborn infants, particularly those born prematurely. There is strong but not definitive evidence that ureaplasmal infection of the lower respiratory tract can lead to development of chronic lung disease in very low-birth-weight infants. Although risk factors for colonization of the lower genitourinary tract have been identified, little information is available concerning risk factors for intrauterine infection and host immune responses to invasive infection. Recent establishment of animal models of respiratory and central nervous system diseases should provide an opportunity to evaluate risk factors, pathogenic mechanisms, and operative immune mechanisms. However, the most critical need is additional information concerning indications for diagnosis and treatment as well as efficacy of treatment.

Hemadsorption by colonies of Ureaplasma urealyticum

Hemadsorption by colonies of Ureaplasma urealyticum and Mycoplasma pneumoniae differed quantitatively and qualitatively. Using standard methodology, few strains of U. urealyticum hemadsorbed; with a modified method, most strains hemadsorbed, indicating a second type of association. Scanning electron microscopy of tannin-osmium-stained preparations showed guinea pig erythrocytes embedded in ureaplasma colonies and craters left when erythrocytes were dislodged.