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

Ureaplasma infections: update on epidemiology, antimicrobial resistance, and pathogenesis

Human Ureaplasma species are being increasingly recognized as opportunistic pathogens in human genitourinary tract infections, infertility, adverse pregnancy, neonatal morbidities, and other adult invasive infections. Although some general reviews have focused on the detection and clinical manifestations of Ureaplasma spp., the molecular epidemiology, antimicrobial resistance, and pathogenesis of Ureaplasma spp. have not been adequately explained. The purpose of this review is to offer valuable insights into the current understanding and future research perspectives of the molecular epidemiology, antimicrobial resistance, and pathogenesis of human Ureaplasma infections. This review summarizes the conventional culture and detection methods and the latest molecular identification technologies for Ureaplasma spp. We also reviewed the global prevalence and mechanisms of antibiotic resistance for Ureaplasma spp. Aside from regular antibiotics, novel antibiotics with outstanding in vitro antimicrobial activity against Ureaplasma spp. are described. Furthermore, we discussed the pathogenic mechanisms of Ureaplasma spp., including adhesion, proinflammatory effects, cytotoxicity, and immune escape effects, from the perspectives of pathology, related molecules, and genetics.

External quality assessment for molecular detection of Ureaplasma urealyticum in China

BACKGROUND AND AIMS

A pilot external quality assessment (EQA) scheme for molecular detection of Ureaplasma urealyticum (UU) was conducted by the National Center for Clinical Laboratories (NCCL) to evaluate the testing capabilities of clinical laboratories and the actual performance of DNA-based nucleic acid amplification tests (NAAT) and RNA-based NAATs when applied in clinical settings.

MATERIALS AND METHODS

The EQA panel contained twelve lyophilized samples, including positive samples containing inactivated cell culture supernatants of UU at different concentrations and sterile saline for negative samples. The positive samples were further divided into three groups of high, moderate and low concentrations. The panels were distributed to the participants and the datasets were analyzed according to the qualitative results.

RESULTS

A total of 365 laboratories participated in the EQA scheme, and 360 results submitted by 338 laboratories were collected, of which 96.11 % (346/360) of the returned results and 95.86 % (324/338) of the laboratories were deemed competent. The positive percentage agreement (PPA) was ≥ 97.5 % for high and moderate concentration samples, but varied significantly for low concentration samples, decreasing from 86.94 % to 51.94 % as the sample concentration decreased. Additionally, for low concentration samples, RNA-based NAAT showed higher PPAs than DNA-based NAATs, but these results were specific to UU supernatants used in this study.

CONCLUSION

Most of UU detection assays employed by the participants were generally consistent with their estimated limit of detection (LOD), and the majority of participants can reliably detect UU samples with high and moderate concentrations, while the poor analytical performance for low concentration samples requires further improvement and optimization.

The Associations of Genital Mycoplasmas with Female Infertility and Adverse Pregnancy Outcomes: a Systematic Review and Meta-analysis

The roles of genital mycoplasmas including Mycoplasma genitalium (M. genitalium), Mycoplasma hominis (M. hominis), Ureaplasma urealyticum (U. urealyticum), and Ureaplasma parvum (U. parvum) in reproductive diseases are equivocal. To investigate whether genital mycoplasmas are risk factors of female infertility and adverse pregnancy outcomes, we performed a systematic review and meta-analysis. Electronic databases were searched for related studies. A random-effects model or fixed-effects model was employed to generate forest plots. Pooled odd ratios (ORs) with 95% confidence intervals (CIs) were applied to measure the strength of associations. Meanwhile, heterogeneity was evaluated by H statistic and I² statistic, and publication bias was explored by funnel plots based on Egger's test and Begg's test. The search yielded 2054 relevant records, and 35 articles were ultimately included for meta-analysis. M. genitalium was a significant risk factor for female infertility (OR, 13.03 [95% CI, 3.46-48.98]) and preterm birth (PTB) (OR, 1.81 [95% CI, 1.17-2.80]), but not for spontaneous abortion (SA) (OR, 0.58 [95% CI, 0.25-1.35]). M. hominis can significantly increase the potential risk of female infertility (OR, 1.56 [95% CI, 1.02-2.38]), SA (OR, 9.14 [95% CI, 4.14-20.18]), stillbirth (OR, 3.98 [95% CI, 1.39-11.36]), and premature rupture of membranes (PROM) (OR, 1.79 [95% CI, 1.26-2.55]), but was not associated with PTB (OR, 1.29 [95% CI, 0.78-2.15]). U. urealyticum had no significant risk effect on female infertility (OR, 0.68 [95% CI, 0.42-1.11]). Coinfections of M. hominis and Ureaplasma were significantly associated with female infertility, SA, and stillbirth, but not with PROM. On the basis of current evidences, this meta-analysis supports that M. genitalium is a risk factor for female infertility and PTB; M. hominis is a potential risk factor for female infertility, SA, stillbirth, and PROM; U. urealyticum has no significant association with female infertility; and the relationship of U. parvum with female infertility and adverse pregnancy outcomes needs to be paid more attention to and remains to be further revealed.

Ureaplasma species and preterm birth: current perspectives

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide, and the human Ureaplasma species are most frequently isolated from the amniotic fluid and placenta in these cases. Ureaplasma colonisation is associated with infertility, stillbirth, histologic chorioamnionitis, and neonatal morbidities, including congenital pneumonia, bronchopulmonary dysplasia, meningitis and perinatal death. The human Ureaplasma spp. are separated into Ureaplasma urealyticum and Ureaplasma parvum with 14 known serotypes. The small genome has several genes, which code for surface proteins; most significantly the Multiple Banded Antigen (MBA) where an antigenic C-terminal domain elicits a host antibody response. Other genes code for various virulence factors such as IgA protease and urease. Ureaplasma spp. infection is diagnosed by culture and polymerase chain reaction (PCR) and commercial assays are available to improve turnaround time. Microbroth dilution assays are routinely used to test antimicrobial susceptibility of clinical Ureaplasma spp. especially against doxycycline, azithromycin, ofloxacin and josamycin. Resistance to macrolides, fluoroquinolones and tetracyclines has been reported. A concise review of Ureaplasma spp. and their role in pregnancy outcomes, especially preterm birth, offers insight into the early diagnosis and appropriate antibiotic therapy to prevent long-term complications of Ureaplasma spp. infections.

Antibacterial Resistance in Ureaplasma Species and Mycoplasma hominis Isolates from Urine Cultures in College-Aged Females

Urinary tract infections (UTIs) affect nearly 20% of women age 15 to 29 and account for an estimated $3.5 billion in costs. Antibiotic resistance prolongs UTI treatment, and resistance profiles vary regionally. This regional variation is an important consideration in guiding empirical treatment selection. Regional studies in the United States have identified tetracycline resistance in over one-third of Ureaplasma species isolates, but no studies have evaluated antibiotic resistance levels in college-aged women with a first-time UTI. We tested a panel of antibiotics and determined the MICs of Ureaplasma species (60 U. parvum and 13 U. urealyticum) and 10 Mycoplasma hominis isolates obtained from urine from college-aged women with a first-time UTI. Low antibiotic resistance was found in this population of women with a first-time UTI. All M. hominis and U. urealyticum isolates were sensitive. However, two U. parvum isolates were resistant, with one to levofloxacin (MIC, 4 μg/ml) and one to tetracycline (MIC, 8 μg/ml). For the Ureaplasma spp., the MIC₉₀s were highest against gentamicin (21 μg/ml) and lowest against doxycycline (0.25 μg/ml). In a comparison of MIC levels between Ureaplasma spp., U. urealyticum had significantly higher MICs against each antibiotic except doxycycline. For the resistant isolates, the genetic mechanisms of resistance were determined. PCR amplification identified tetM to be present in the tetracycline-resistant isolate and an S83W mutation within the parC gene of the quinolone-resistant isolate. To our knowledge, this study is the first to provide molecular and phenotypic evidence of the S83W parC mutation conferring levofloxacin resistance in U. parvum isolated from a patient in the United States.

Ureaplasma parvum genotype, combined vaginal colonisation with Candida albicans, and spontaneous preterm birth in an Australian cohort of pregnant women

BACKGROUND

Detection of Ureaplasma, Mycoplasma and Candida spp. in the vagina during pregnancy has previously been associated with preterm birth (PTB). However, the prevalence of these microorganisms and the associated obstetric risks (likely to be population-specific) have not been determined in Australian women; furthermore, in the case of Ureaplasma spp., very few studies have attempted characterisation at the species level and none have examined genotype/serovar status to further refine risk assessment.

METHODS

In order to address these issues we sampled the vaginal fluid of 191 pregnant Australian women at three time points in pregnancy. Culture methods were used for detection of Ureaplasma spp. and Candida spp., and real-time PCR was used for speciation of U. parvum and U. urealyticum, non-albicans Candida spp., Mycoplasma hominis and Mycoplasma genitalium. High-resolution melt PCR was used to genotype U. parvum. Data on various lifestyle factors (including sex during pregnancy and smoking), antimicrobial use and pregnancy outcome were collected on all participants. Chi-square tests were used to assess the association of vaginal microorganisms with PTB.

RESULTS

Detection of Ureaplasma spp. was higher among spontaneous PTB cases, specifically in the presence of U. parvum [77 % preterm (95 % confidence interval (CI) 50-100 %) vs. 36 % term (CI: 29-43 %), p = 0.004], but not U. urealyticum. The association with PTB strengthened when U. parvum genotype SV6 was detected (54 % preterm (CI: 22-85 %) vs. 15 % term (CI: 10-20 %), p = 0.002); this genotype was also present in 80 % (4/5) of cases of PTB <34 weeks gestation. When present with Candida albicans in the same sample, the association with PTB remained strong for both U. parvum [46 % preterm (CI: 15-78 %) vs. 13 % term (CI: 8-18 %), p = 0.005] and U. parvum genotype SV6 [39 % preterm (CI: 8-69 %) vs. 7 % term (CI: 3-11 %), p = 0.003]. With the exception of Candida glabrata, vaginal colonisation status for all organisms was stable throughout pregnancy. Smoking significantly increased the likelihood of detection of all target organisms.

CONCLUSIONS

These data suggest that the presence of different species and serovars of Ureaplasma spp. in the vagina confers an increased risk of spontaneous PTB, findings which may be useful in risk assessment for identifying women who would benefit from antimicrobial treatment.

Molecular characterisation of Mycoplasma species isolated from the genital tract of Dorper sheep in South Africa

Biochemical and molecular analysis were conducted on 34 strains of Mycoplasma species isolated between 2003 and 2009 from the genital tract of clinically healthy Dorper sheep and sheep with ulcerative vulvitis and balanitis. Earlier publications identified the causative agent as Mycoplasma mycoides mycoides large colony (MmmLC) and Arcanobacterium pyogenes. The aims of the study were to characterise Mycoplasma species isolated from the genital tract of Dorper sheep with polymerase chain reaction assay, cloning and gene sequencing. Basic Local Alignment Search Tool (BLAST) results revealed six predominant Mycoplasma species: Mycoplasma arginini, Mycoplasma bovigenitalium, Arcanobacterium laidlawii, MmmLC, Mycoplasma sp. ovine/caprine serogroup II and M. canadense. Sequencing of the 34 isolates were analysed using phylogenetic methods, and 18 (50%) were identified as M. arginini with 99% - 100% similarity to M. arginini from England and Sweden. Six isolates showed 99% similarity to M. bovigenitalium strains from Turkey and Germany. Two isolates had 99% similarity to an M. sp. ovine/caprine sero group II from the United Kingdom. BLAST for two isolates revealed 99% similarity to Acholeplasma laidlawii from India, another two were 99% similar to MmmLC strain from Sweden, two showed 98% similarity to Mycoplasma sp. Usp 120 from Brazil, and two isolates have a 97% - 99% similarity to M. mm. Jcv1 strain from the United States of America. Finally, one isolate showed similarity of 99% to Mycoplasma canadense strain from Italy. The findings support the hypothesis that ulcerative vulvitis and balanitis of Dorper sheep in South Africa (SA) is a multifactorial disease with involvement of different Mycoplasma species.

Comparison between culture and a multiplex quantitative real-time polymerase chain reaction assay detecting Ureaplasma urealyticum and U. parvum

A novel multiplex quantitative real-time polymerase chain reaction (qPCR) for simultaneous detection of U. urealyticum and U. parvum was developed and compared with quantitative culture in Shepard's 10 C medium for ureaplasmas in urethral swabs from 129 men and 66 women, and cervical swabs from 61 women. Using culture as the gold standard, the sensitivity of the qPCR was 96% and 95% for female urethral and cervical swabs, respectively. In male urethral swabs the sensitivity was 89%. The corresponding specificities were 100%, 87% and 99%. The qPCR showed a linear increasing DNA copy number with increasing colour-changing units. Although slightly less sensitive than culture, this multiplex qPCR assay detecting U. urealyticum and U. parvum constitutes a simple and fast alternative to the traditional methods for identification of ureaplasmas and allows simultaneous species differentiation and quantitation in clinical samples. Furthermore, specimens overgrown by other bacteria using the culture method can be evaluated in the qPCR.

Development of a multilocus sequence typing scheme for Ureaplasma

Ureaplasma is a commensal of the human urogenital tract but is always associated with invasive diseases such as non-gonococcal urethritis and infertility adverse pregnancy outcomes. To better understand the molecular epidemiology and population structure of Ureaplasma, a multilocus sequence typing (MLST) scheme based on four housekeeping genes (ftsH, rpL22, valS, thrS) was developed and validated using 283 isolates, including 14 serovars of reference strains and 269 strains obtained from clinical patients. A total of 99 sequence types (STs) were revealed: the 14 type strains of the Ureaplasma serovars were assigned to 12 STs, and 87 novel and special STs appeared among the clinical isolates. ST1 and ST22 were the predominant STs, which contained 68 and 70 isolates, respectively. Two clonal lineages (CC1 and CC2) were shown by eBURST analysis, and linkage disequilibrium was revealed through a standardized index of association (I A (S)). The neighbor-joining tree results of 14 Ureaplasma serovars showed two genetically significantly distant clusters, which was highly congruent with the species taxonomy of ureaplasmas [Ureaplasma parvum (UPA) and Ureaplasma urealyticum (UUR)]. Analysis of the biotypes of 269 clinical isolates revealed that all the isolates of CC1 were UPA and those of CC2 were UUR. Additionally, CC2 was found more often in symptomatic patients with vaginitis, tubal obstruction, and cervicitis. In conclusion, this MLST scheme is adequate for investigations of molecular epidemiology and population structure with highly discriminating capacity.

Molecular methods for the detection of Mycoplasma and ureaplasma infections in humans: a paper from the 2011 William Beaumont Hospital Symposium on molecular pathology

Mycoplasma and Ureaplasma species are well-known human pathogens responsible for a broad array of inflammatory conditions involving the respiratory and urogenital tracts of neonates, children, and adults. Greater attention is being given to these organisms in diagnostic microbiology, largely as a result of improved methods for their laboratory detection, made possible by powerful molecular-based techniques that can be used for primary detection in clinical specimens. For slow-growing species, such as Mycoplasma pneumoniae and Mycoplasma genitalium, molecular-based detection is the only practical means for rapid microbiological diagnosis. Most molecular-based methods used for detection and characterization of conventional bacteria have been applied to these organisms. A complete genome sequence is available for one or more strains of all of the important human pathogens in the Mycoplasma and Ureaplasma genera. Information gained from genome analyses and improvements in efficiency of DNA sequencing are expected to significantly advance the field of molecular detection and genotyping during the next few years. This review provides a summary and critical review of methods suitable for detection and characterization of mycoplasmas and ureaplasmas of humans, with emphasis on molecular genotypic techniques.

Comparative genome analysis of 19 Ureaplasma urealyticum and Ureaplasma parvum strains

Background

Ureaplasma urealyticum (UUR) and Ureaplasma parvum (UPA) are sexually transmitted bacteria among humans implicated in a variety of disease states including but not limited to: nongonococcal urethritis, infertility, adverse pregnancy outcomes, chorioamnionitis, and bronchopulmonary dysplasia in neonates. There are 10 distinct serotypes of UUR and 4 of UPA. Efforts to determine whether difference in pathogenic potential exists at the ureaplasma serovar level have been hampered by limitations of antibody-based typing methods, multiple cross-reactions and poor discriminating capacity in clinical samples containing two or more serovars.

Results

We determined the genome sequences of the American Type Culture Collection (ATCC) type strains of all UUR and UPA serovars as well as four clinical isolates of UUR for which we were not able to determine serovar designation. UPA serovars had 0.75−0.78 Mbp genomes and UUR serovars were 0.84−0.95 Mbp. The original classification of ureaplasma isolates into distinct serovars was largely based on differences in the major ureaplasma surface antigen called the multiple banded antigen (MBA) and reactions of human and animal sera to the organisms. Whole genome analysis of the 14 serovars and the 4 clinical isolates showed the mba gene was part of a large superfamily, which is a phase variable gene system, and that some serovars have identical sets of mba genes. Most of the differences among serovars are hypothetical genes, and in general the two species and 14 serovars are extremely similar at the genome level.

Conclusions

Comparative genome analysis suggests UUR is more capable of acquiring genes horizontally, which may contribute to its greater virulence for some conditions. The overwhelming evidence of extensive horizontal gene transfer among these organisms from our previous studies combined with our comparative analysis indicates that ureaplasmas exist as quasi-species rather than as stable serovars in their native environment. Therefore, differential pathogenicity and clinical outcome of a ureaplasmal infection is most likely not on the serovar level, but rather may be due to the presence or absence of potential pathogenicity factors in an individual ureaplasma clinical isolate and/or patient to patient differences in terms of autoimmunity and microbiome.

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.

The role of Genital Mycoplasmas for the development of urogenital pathology in children

Modern data of the epidemiological aspects and clinical peculiarities of inflammatory urogenital diseases caused by genital mycoplasmas in children are represented. Contemporary methods of laboratory diagnostics and therapy for inflammatory urogenital diseases caused by genital mycoplasmas are described.

Ureaplasma antigenic variation beyond MBA phase variation: DNA inversions generating chimeric structures and switching in expression of the MBA N-terminal paralogue UU172

Phase variation of the major ureaplasma surface membrane protein, the multiple-banded antigen (MBA), with its counterpart, the UU376 protein, was recently discussed as a result of DNA inversion occurring at specific inverted repeats. Two similar inverted repeats to the ones within the mba locus were found in the genome of Ureaplasma parvum serovar 3; one within the MBA N-terminal paralogue UU172 and another in the adjacent intergenic spacer region. In this report, we demonstrate on both genomic and protein level that DNA inversion at these inverted repeats leads to alternating expression between UU172 and the neighbouring conserved hypothetical ORF UU171. Sequence analysis of this phase-variable ‘UU172 element’ from both U. parvum and U. urealyticum strains revealed that it is highly conserved among both species and that it also includes the orthologue of UU144. A third inverted repeat region in UU144 is proposed to serve as an additional potential inversion site from which chimeric genes can evolve. Our results indicate that site-specific recombination events in the genome of U. parvum serovar 3 are dynamic and frequent, leading to a broad spectrum of antigenic variation by which the organism may evade host immune responses.

Detection and characterization of human Ureaplasma species and serovars by real-time PCR

We designed primers and probes for the detection and discrimination of Ureaplasma parvum and U. urealyticum and their 14 serovars by real-time PCR. The analytical sensitivity and specificity of the multiplex species-specific PCR were determined by testing corresponding American Type Culture Collection (ATCC) type strains, 47 other microbial species, and human genomic DNA. The limits of the multiplex PCR were 2.8 x 10(-2) CFU/microl PCR mixture for detecting U. parvum and 4.1 x 10(-2) CFU/microl PCR mixture for detecting U. urealyticum. Clinical specificity and sensitivity were proven by comparison with culture and traditional PCR. For the detection of any Ureaplasma species, the clinical sensitivity and specificity of real-time PCR were 96.9% and 79.0%, respectively, using culture as a reference. Multiplex real-time PCR was also more sensitive than traditional PCR in discriminating the two Ureaplasma species in culture-positive subcultures. Each of the 14 monoplex serovar-specific PCR assays was specific for the corresponding ATCC type strain serovar. This new species identification PCR is specific and sensitive in the detection of Ureaplasma species in clinical specimens, and the serovar-specific PCR assays are the first set of complete genotypic assays to differentiate all 14 known Ureaplasma serovars. These assays provide quick and reliable means for investigating the epidemiology and pathogenicity of ureaplasmas at the serovar level.

Prevalence of Ureaplasma urealyticum and Ureaplasma parvum in semen of infertile and healthy men

Ureaplasma urealyticum is a causative agent of non-gonococcal urethritis and is implicated in the pathogenesis of prostatitis, epididymitis and infertility. The organism is more common in partners of infertile than fertile marriages. U. urealyticum infections not only jeopardize fertility but also pose a risk for infertility treatment and resulting pregnancies. The aim of this study was to determine the prevalence of U. urealyticum and Ureaplasma parvum in semen of infertile and healthy men by polymerase chain reaction (PCR). Semen samples were obtained from infertile patients and healthy controls and were subjected to the routine andrological analysis and PCR. DNA was extracted by the Cadieux method, and analysed by PCR protocol with specific primers for urease and multiple-banded antigen genes. Ureaplasmas were detected significantly by PCR in 12 of 100 (12%) semen specimens from infertile patients and in three of 100 (3%) healthy men. The volume of semen fluid, concentration of sperm cells, and sperm cell with normal morphology were significantly decreased in infertile men. In the group of infertile patients with PCR positive for Ureaplasmas, the volume, count and morphology of semen samples were lower than in the infertile patients with PCR-negative results. U. urealyticum species in semen of infertile men was found to be high (9%) than in healthy controls (1%). Detection rate for U. parvum was 3% in the infertile group and 2% in healthy men. The results indicate that U. urealyticum species is more common in specimens of infertile men. The percentage of normal sperm cells, the volume of semen and the percentage of sperm cells with motility in the PCR positive for U. urealyticum species group were lower than in the PCR positive for U. parvum group.

Detection of Ureaplasma urealyticum in semen of infertile men by PCR

Ureaplasma urealyticum is a causative agent ofnon-gonococcal urethritis, prostatitis, epididymitis and infertility. The organism is more common in partners of infertile than fertile marriages. U. urealyticum infections not only jeopardize fertility but also pose a risk for infertility treatment and resulting pregnancies. The purpose of this study was to determine the prevalence of U. urealyticum in semen of infertile and healthy men by Polymerase Chain Reaction (PCR). Semen samples were obtained from infertile patients and healthy control and were subjected to the routine andrological analysis and PCR. DNA was extracted by Cadieux method and analyzed by PCR protocol with species-specific primers for U. urealyticum (urease gene). U. urealyticum was detected significantly by PCR in 12 of 100 (12%) semen specimens from infertile patients and in 3 of 100 (3%) healthy men. The volume of semen fluid, concentration of sperm cells and sperm cell with normal morphology were significantly decreased in infertile men. In the group of infertile patients with PCR positive for U. urealyticum the volume, count and morphology of semen samples were lower than in the infertile patients with PCR negative results.

Quantitative detection of Ureaplasma parvum (biovar 1) and Ureaplasma urealyticum (biovar 2) in urine specimens from men with and without urethritis by real-time polymerase chain reaction

BACKGROUND

We previously reported a significant association between Ureaplasma urealyticum (biovar 2) and nongonococcal urethritis (NGU). We also found that the presence of Ureaplasma parvum (biovar 1) in the male urethra might be the result of colonization.

OBJECTIVE

The objective of this study was to clarify the pathogenic role of human Ureaplasma in NGU by assessing the association of bacterial loads with clinical findings and inflammatory responses in the urethra.

STUDY DESIGN

The 16S rRNA gene of Ureaplasma was quantified by a TaqMan-based real-time polymerase chain reaction assay in first-pass urine from 37 men with Ureaplasma-positive nonmycoplasmal nonchlamydial NGU (NMNCNGU) and 30 Ureaplasma-positive men without urethritis.

RESULTS

U. urealyticum (biovar 2) loads in 23 men with NMNCNGU were significantly higher than those in 14 men without urethritis. However, U. parvum (biovar 1) loads did not differ significantly between 14 men with NMNCNGU and 20 men without urethritis.

CONCLUSION

The association of increased U. urealyticum (biovar 2) loads with symptomatic urethritis suggests that U. urealyticum (biovar 2) may be a pathogen of NGU. Our results also suggest that the presence of U. parvum (biovar 1) may not be significant in the development of NGU.

Ureaplasma infection and neonatal lung disease

Infection with the ureaplasmas may occur in utero or perinatally in prematurely born infants. For some infants, infection with these organisms triggers a vigorous pro-inflammatory response in the lungs and increases the risk of developing bronchopulmonary dysplasia (BPD). At present, there is insufficient evidence from clinical trials to determine whether antibiotic treatment of Ureaplasma has any influence on the development of BPD and its comorbidities. Future investigation in the context of well-designed, adequately powered controlled clinical trials should focus on determining whether treatment of ureaplasmal infection lessens lung inflammation, decreases rates of BPD, and improves long-term, neurodevelopmental outcome.

Comparative genome analysis of Ureaplasma parvum clinical isolates

Ureaplasma parvum colonizes human mucosal surfaces, primarily in the respiratory and urogenital tracts, causing a wide spectrum of diseases, from non-gonococcal urethritis to pneumonitis in immunocompromised hosts. Although the basis for these diverse clinical outcomes is not yet understood, more severe disease may be associated with strains harboring a certain set of strain-specific genes. To investigate this, whole genome DNA macroarrays were constructed and used to assess genomic diversity in 10 U. parvum clinical strains. We found that 7.6% of U. parvum genes were dispersed into one or more strains, thus defining a minimal functional core of 538 U. parvum genes. Most of the strain-specific genes (79%) were of unknown function and were unique to U. parvum. Four hypervariable plasticity regions were identified in the genome containing 93% of the variability in the gene pool (UU32-UU33, UU145-UU170, UU440-UU447 and UU527-UU529). We hypothesized that one of them (UU145-UU170) was a pathogenicity island in U. parvum and we characterized it. Thus, we propose that the clinical outcome of U. parvum infection is probably associated with this newly identified pathogenicity island.

Molecular evidence of Ureaplasma urealyticum and Ureaplasma parvum colonization in preterm infants during respiratory distress syndrome

BACKGROUND

Ureaplasma urealyticum and U. parvum have been associated with respiratory diseases in premature newborns, but their role in the pathogenesis of the respiratory distress syndrome (RDS) is unclear. The aim of this study was to detect, using molecular techniques, the role of Mycoplasma spp. and Ureaplasma spp. in respiratory secretion and blood specimens of preterm newborns with or without RDS and to evaluate the prevalence of perinatal U. urealyticum or U. parvum infection. The influence of chemotherapy on the clinical course was also evaluated.

METHODS

Tracheal aspirate or nasopharingeal fluid samples from 50 preterm babies with (24) or without RDS (26) were analysed for detection of U. urealyticum and U. parvum by culture identification assay and PCR. Sequencing analysis of amplicons allowed us to verify the specificity of methods. Clarithromycin (10 mg kg-1 twice a day) was administered in ureaplasma-positive patients who presented clinical signs of RDS.

RESULTS

15/24 neonates with RDS (p < 0.001) and 4/26 without RDS were found PCR-positive for U. urealyticum or U. parvum. Culture identification assay was positive in 5/50 newborns, three of which with RDS. Sequencing analyses confirmed the specificity of these methods. Association of patent ductus arteriosus with ureaplasma colonization was more statistically significant (p = 0.0004) in patients with RDS than in those without RDS.

CONCLUSION

Colonization of the lower respiratory tract by Ureaplasma spp. and particularly by U. parvum in preterm newborns was related to RDS. The routine use of molecular methods could be useful to screen candidate babies for etiologic therapy.

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.

Mycoplasmas in semen of chronic prostatitis patients

OBJECTIVE

To evaluate the occurrence of mycoplasmas in the semen of chronic prostatitis patients.

MATERIAL AND METHODS

Genital mycoplasmas (Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Ureaplasma parvum) were sought in the semen of 121 chronic prostatitis patients [38 National Institutes of Health (NIH) category IIIa, 59 NIH category IIIb and 24 NIH category IV] and 40 controls. The commercially available kit Mycoplasma IST was applied to the semen samples of all 161 men, and polymerase chain reaction (PCR) to those of 60 randomly selected men.

RESULTS

Ureaplasmas were found in all study groups (at frequencies ranging from 12% to 25%) using the Mycoplasma IST test, but M. hominis was found only in one NIH category IIIb patient. Using PCR, most of the ureaplasmas appeared to be U. parvum, which was found in all prostatitis groups (18% of NIH category IIIa, 15% of NIH category IIIb and 25% of NIH category IV patients) but not in the controls. M. genitalium was found in 18% of the NIH category IIIa patients. All of the mycoplasmas occurred significantly more frequently in prostatitis patients than in controls and in NIH category IIIa patients than in controls.

CONCLUSION

Mycoplasmas occur more frequently in the semen of prostatitis patients than in that of healthy controls, with U. parvum being the most frequently occurring species.

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.

Polymerase chain reaction-based subtyping of ureaplasma parvum and ureaplasma urealyticum in first-pass urine samples from men with or without urethritis

BACKGROUND

Our previous study suggested a significant association between Ureaplasma urealyticum and nongonococcal urethritis (NGU). However, association of the serovars of U. urealyticum with NGU remains unclear. A polymerase chain reaction (PCR)-based assay can distinguish 4 serovars of Ureaplasma parvum from each other and categorize 10 serovars of U. urealyticum into 3 subtypes: subtype 1 (serovars 2, 5, 8, and 9), subtype 2 (serovars 4, 10, 12, and 13), and subtype 3 (serovars 7 and 11).

GOAL

The goal of this study was to determine which subtypes of U. urealyticum are associated with NGU as determined by PCR-based assay.

STUDY

The prevalence of U. urealyticum subtypes in 106 ureaplasma-positive men with urethritis was compared with that in 30 ureaplasma-positive men without urethritis.

RESULTS

: In men with nonchlamydial NGU and men with Mycoplasma genitalium-negative nonchlamydial NGU, only U. urealyticum subtype 1 (serovars 2, 5, 8, and 9) was detected significantly more often than in men without urethritis.

CONCLUSION

This study suggests that subtype 1 of U. urealyticum (serovars 2, 5, 8, and 9) is associated with NGU independently of Chlamydia trachomatis or M. genitalium.

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.

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

AIM

To use polymerase chain reaction (PCR)-microtiter plate hybridization assays to detect Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum (biovar 1) and Ureaplasma urealyticum (biovar 2) in first-voided urine specimens from patients with non-gonococcal urethritis (NGU).

METHODS

A total of 153 male patients with NGU, who visited one of 24 clinics in Japan, were recruited for this study. All were examined using PCR-microtiter plate hybridization assays for the presence of M. genitalium, M. hominis, U. parvum (biovar 1) and U. urealyticum (biovar 2) in first-voided urine specimens. They were also examined for the presence of Chlamydia trachomatis.

RESULTS

Of these 153 patients, 73 (47.7%) were positive for C. trachomatis. Overall, the prevalence was 17.0% for M. genitalium, 16.3% for U. urealyticum (biovar 2), 7.8% for U. parvum (biovar 1) and 2.6% for M. hominis. In the 80 patients with non-chlamydial NGU, the prevalence of M. genitalium, U. urealyticum (biovar 2), U. parvum (biovar 1) and M. hominis was 23.8%, 18.8%, 8.8% and 2.6%, respectively.

CONCLUSIONS

This study shows the prevalence of mycoplasmas and ureaplasmas in NGU in Japan. M. genitalium and U. urealyticum (biovar 2) might be pathogens of NGU and could be associated with persistent and recurrent urethritis. When patients with NGU are treated, such pathogens should be taken into account. This PCR-microtiter plate hybridization assay provides a useful method for diagnosing NGU caused by M. genitalium and U. urealyticum (biovar 2).

Association of Ureaplasma urealyticum (biovar 2) with nongonococcal urethritis

BACKGROUND

The tiny (T)-strain mycoplasmas, designated in 1974 as Ureaplasma urealyticum, have been divided into 2 species, Ureaplasma parvum (biovar 1) and U. urealyticum (biovar 2), but association of each of these species with nongonococcal urethritis (NGU) remains unclear.

GOAL

The goal of this study was to determine whether U. parvum (biovar 1) or U. urealyticum (biovar 2) is associated with NGU.

STUDY DESIGN

The prevalences of U. parvum (biovar 1) and U. urealyticum (biovar 2) in 572 patients with urethritis were compared with those in 141 men without urethritis.

RESULTS

The prevalence of U. urealyticum (biovar 2) in men with NGU (15.8%) or with nonchlamydial NGU (18.0%) was significantly higher than that in men without urethritis (7.8%). The prevalence of U. parvum (biovar 1) in men with NGU (8.5%) or with nonchlamydial NGU (11.1%) did not differ significantly from that in men without urethritis (13.5%).

CONCLUSION

Our results showed a significant association between U. urealyticum (biovar 2) and NGU. They also suggest that the presence of U. parvum (biovar 1) in the male urethra might be the result of colonization.

PCR methods in clinical investigations of human ureaplasmas: a minireview

Human ureaplasmas are small, cell-wall-deficient organisms that are implicated in many human infections. Due to their small size and fastidious growth requirements, ureaplasmal infections are hard to diagnose clinically, and ureaplasmal disease is difficult to study in clinical samples. Standard culture methods for ureaplasmas are technically challenging, and 3 to 5 days are required to identify this pathogen. PCR methods have been increasingly used in the diagnosis of these infections and in the study of this pathogen in human specimens from multiple sites. These methods have theoretical advantages over traditional culture methods. Organism identification can occur in the presence of low numbers of bacteria, and viability is not necessary. Rapid identification of organisms within 24 h is also possible. In addition, subtyping of isolates can be performed faster with PCR methods than with culture methods. The use of PCR methods in translational research in multiple human ureaplasmal diseases will be reviewed in this paper, and their usefulness will be compared to culture methods.

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.

Ureaplasma urealyticum in the development of postpartum endometritis

OBJECTIVE

Investigation of the clinical significance of Ureaplasma urealyticum and its biovars in the development of postpartum endometritis.

STUDY DESIGN

Cervical swabs were cultured for U. urealyticum in women presenting endometritis. The positive U. urealyticum cultures (>10(5) cfu/ml) (study group) were compared with those from women without endometritis (control group). Anti-Ureaplasma antibodies were measured and U. urealyticum biovars were determined by polymerase chain reaction.

RESULTS

There was no difference between the prevalence of U. urealyticum in the cervical swabs of both groups, however, the number of cfu per culture, showed a significant difference between study and control groups. Out of the culture positive endometritis patients 39% (26/67) had >10(5) cfu/ml compared to 17% of control patients (5/30) P=0.03. No significant disparity between both the groups was found in the prevalence of the parvo biovar (77% versus 71.5%, respectively). The difference in anti-Ureaplasma antibodies reached no statistical significance (30% versus 18% in study and control groups, respectively).

CONCLUSIONS

The significant difference in U. urealyticum culture cfu between both groups suggests that U. urealyticum may play a role in the etiology of this infection. This involvement is dependent not only on the presence or absence of U. urealyticum in the culture, but on its colonization rate in the cervix (>10(5) cfu/ml).

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.

Identification and quantification of ureaplasmas colonizing the respiratory tract and assessment of their role in the development of chronic lung disease in preterm infants

BACKGROUND

The role of Ureaplasma urealyticum in the development of chronic lung disease (CLD) in preterm infants continues to be disputed. Recently U. urealyticum has been found to consist of two species, U. urealyticum and Ureaplasma parvum, a finding that has not been considered in previous studies of CLD. This study examined the possible relationships between development of CLD and respiratory colonization by these newly redefined species, their concentrations in lower respiratory secretions and the effect of pulmonary surfactant treatment on these relationships in preterm infants with birth weights < 1500 g.

METHODS

Endotracheal aspirates (ETA) were collected from intubated infants when airway suctioning was medically required. ETA were stored at -80 degrees C until quantitative cultures for ureaplasmas and Mycoplasma hominis were performed. Culture results were correlated with development of CLD.

RESULTS

Of 475 infants (birth weights < 1500 g) admitted during the 2-year study period, 272 were excluded because they were not intubated or were extubated before ETA could be obtained. An additional 28 infants died, were discharged or were transferred before they could be assessed for CLD. From the remaining 175 infants ureaplasmas were isolated from 66 (38%). No statistically significant associations were identified between development of CLD and the Ureaplasma species isolated, or concentration of ureaplasmas in lower respiratory secretions. These findings were not altered by treatment with pulmonary surfactant (Survanta).

CONCLUSION

Lower respiratory colonization by ureaplasmas does not appear to be a contributory cause of CLD in preterm infants.

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.

A physical and genetic map of the Mycoplasma hyopneumoniae strain J genome

A macrorestriction map of the genome of Mycoplasma hyopneumoniae strain J, the type strain of the causative agent of enzootic pneumonia in pigs, was constructed using pulsed-field gel electrophoresis (PFGE) and DNA hybridization. The size of the genome as determined by PFGE was approximately 1070 kb. Assembly of the M. hyopneumoniae genomic map was facilitated and complimented by the simultaneous construction of an ordered cosmid library. Five contigs of overlapping cosmids were assembled, which together represent coverage of approximately 728 kb. Forty-two genetic markers (including three types of repeated elements) were placed on the M. hyopneumoniae map. Closer examination of an ApaI restriction fragment contained entirely within a single cosmid insert suggests that the genome size may be overestimated by PFGE.

Species identification and subtyping of Ureaplasma parvum and Ureaplasma urealyticum using PCR-based assays

There is good evidence that the organism currently known as Ureaplasma urealyticum should be divided into two species-U. parvum (previously U. urealyticum biovar 1) and U. urealyticum (previously U. urealyticum biovar 2). In this study, we designed a series of primers, targeting the 16S rRNA gene and 16S rRNA-23S rRNA intergenic spacer regions, the urease gene subunits, and the 5' ends of the multiple-banded antigen (MBA) genes, to identify and subtype these Ureaplasma species. All of the species-specific primer pairs could distinguish the two species, but only subtype-specific primer pairs targeting the MBA genes could distinguish subtypes within each species. U. parvum was separated into three subtypes, represented by serovars 1, 3/14, and 6. U. urealyticum was also separated into three subtypes by PCR and/or direct sequencing. Subtype 1 consisted of serovars 2, 5, 8, and 9; subtype 2 contained serovars 4, 10, 12, and 13; and subtype 3 contained serovars 7 and 11. A selection of primer pairs was used to identify and subtype 78 clinical ureaplasma isolates from vaginal swabs of pregnant women and to identify and subtype ureaplasmas directly in 185 vaginal swabs in which they had been previously detected. U. parvum was identified in 228 (87%) of 263 isolates or specimens, and U. urealyticum was identified in 50 (19%) (both were present in 6%). Serovars 3/14 (48%) and 1 (43%) were most common among U. parvum isolates, and subtypes 2 (62%) and 1 (34%) were most common among U. urealyticum isolates. This new PCR-based typing system will facilitate future studies of the relationship between individual Ureaplasma species or subtypes and human disease.

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.

Effects of Mycoplasma fermentans incognitus on differentiation of THP-1 cells

Mycoplasma fermentans incognitus has been isolated from human tissue in patients both with and without AIDS who died of systemic infection. M. fermentans incognitus and other strains of M. fermentans have been associated with rheumatoid arthritis. While cell extracts of M. fermentans incognitus can induce changes in murine and human cells of the monocytic lineage, little is known about interactions of viable organisms with such cells. Because of the central role of macrophages in chronic inflammation, we examined the effects of M. fermentans incognitus on surface markers and functions of THP-1 cells, a well-characterized human monocytic cell line. This cell line has been used extensively in studies of macrophage differentiation, especially following exposure to phorbol esters. Changes in cell morphology, phagocytosis, rate of cell division, and selected surface markers were evaluated in cultures of THP-1 cells exposed to phorbol myristate acetate (PMA), M. fermentans incognitus, or both. As reported by other investigators, PMA induced THP-1 cells to differentiate into cells resembling tissue macrophages. M. fermentans incognitus only minimally affected changes induced by PMA, slightly increasing the percentage of cells positive for FCgammaRI and major histocompatibility complex (MHC) class II antigens. M. fermentans incognitus alone induced an incomplete arrest in the cell cycle at G0 phase, increased phagocytic ability, and enhanced expression of FCgammaRI, CR3, CR4, and MHC class II antigens.

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.

Detection of Ureaplasma urealyticum by PCR and biovar determination by liquid hybridization

An assay which combines the direct detection of Ureaplasma urealyticum with biovar determination was developed and applied to 618 urogenital specimens. U. urealyticum was detected by inhibitor-controlled PCR. A 429-bp fragment of the urease gene was amplified. The amplicons were labelled with digoxigenin during PCR. Biovar determination was performed by liquid hybridization with biotin-labelled biovar-specific probes, and the hybrids were detected with peroxidase-conjugated sheep anti-digoxigenin immunoglobulin G Fab fragments. Results of PCR and culture for 453 urogenital specimens from women and 105 urethral specimens from men could be compared. Among the specimens from women, 63% were PCR positive as well as culture positive, 0.9% were positive only by PCR, and 4% were positive only by culture. Among the specimens from men, 15% were PCR positive as well as culture positive, 1% were positive only by PCR, and 9% were positive only by culture. By using culture as the reference method, the PCR had a sensitivity of 94% and a specificity of 98% when applied to specimens from women and a sensitivity of 64% and a specificity of 99% when applied to specimens from men. Overall, 80% of the PCR-positive specimens contained biovar 1,13.5% contained biovar 2, and 6.5% contained both biovars.

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.

Detection of Ureaplasma urealyticum in endotracheal tube aspirates from neonates by PCR

A PCR-based test was optimized for the detection of Ureaplasma urealyticum from neonatal respiratory specimens, with primers directed against the multiple-banded antigen gene (L. J. Teng, X. Zheng, J. I. Glass, H. Watson, J. Tsai, and G. H. Cassell, J. Clin. Microbiol. 32:1464-1469, 1994). Endotracheal tube aspirates (225) from 103 low-birth-weight neonates (<1,250 g) were taken, when possible, at days 0, 4, and 14 after birth and examined by culture and by PCR. Of 77 specimens positive by either method, 73 were detected by PCR and 60 were detected by culture. Overall, 36% of the neonates were positive for U. urealyticum by either method. Of 16 patients with PCR-positive-culture-negative results, 13 had positive cultures at another sampling point, and one additional patient had a twin with positive cultures. Of 11 patients with day 0 specimens positive by PCR alone, 9 subsequently became culture positive, demonstrating the utility of this test in early detection. Multiple serovars were present in over 50% of positive specimens, with serovars 3 and 14 in combination being most prevalent. The amplicon size generated from the specimen by PCR correctly predicted the biovars isolated in over 85% of positive specimens. Thus, this PCR test was valuable in allowing early detection of U. urealyticum in neonatal respiratory specimens, as well as in providing biovar information.

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.

Biovar diversity is reflected by variations of genes encoding urease of Ureaplasma urealyticum

Five oligonucleotide primers derived from the gene encoding urease of Ureaplasma urealyticum were designed to evaluate the relationship between the urease gene and biovar diversity of this organism. Five combinations of these primers were tested by PCR and the result revealed that there were variations in urease genes among different serovars of U. urealyticum. This result, in agreement with other PCRs based on other functionally unrelated (rRNA and MB antigen) genes, may reflect the phylogenetic relationship among organisms taxonomically classified as U. urealyticum.