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

Diagnosis and management of clinical chorioamnionitis

Chorioamnionitis is a common complication of pregnancy associated with significant maternal, perinatal, and long-term adverse outcomes. Adverse maternal outcomes include postpartum infections and sepsis whereas adverse infant outcomes include stillbirth, premature birth, neonatal sepsis, chronic lung disease, and brain injury leading to cerebral palsy and other neurodevelopmental disabilities. Research in the past 2 decades has expanded understanding of the mechanistic links between intra-amniotic infection and preterm delivery as well as morbidities of preterm and term infants. Recent and ongoing clinical research into better methods for diagnosing, treating, and preventing chorioamnionitis is likely to have a substantial impact on short and long-term outcomes in the neonate.

Placental features of chorioamnionitis colonized with Ureaplasma species in preterm delivery

Ureaplasma spp. is detected in the urogenital tract, including the vagina, cervix, chorioamnion, and placenta. Their colonization is associated with histologic chorioamnionitis (CAM), often observed in placentas from preterm delivery. We isolated Ureaplasma spp. from 63 preterm placentas among 151 specimens, which were delivered at <32 wk of gestation. Of the 63 placentas, 52 (83%) revealed CAM in cultures positive for Ureaplasma spp., however, CAM was observed only in 30% (26/88) of cultures negative for Ureaplasma spp. (p < 0.01). Colonization by Ureaplasma spp. was an independent risk factor for CAM (OR, 11.27; 95% CI, 5.09-24.98). Characteristic neutrophil infiltration was observed in the amnion and subchorion (bistratified pattern) in cultures positive for Ureaplasma spp. FISH analysis of CAM placenta with male infant pregnancy indicated that bistratified infiltrated neutrophils showed the XX karyotype and umbilical vein infiltrated neutrophils showed XY karyotype. The distribution of sulfoglycolipid, the receptor of Ureaplasma spp., was mainly detected in the amnion. Ureaplasmal urease D protein and ureB gene were both detected in the amnion, indicating direct colonization by Ureaplasma spp.

Diversity in cytokine response to bacteria associated with preterm birth by fetal membranes

OBJECTIVE

This study compared cytokine and prostaglandin (PG) responses by fetal membranes stimulated with 4 different bacterial species associated with preterm birth (PTB).

STUDY DESIGN

Fetal membranes (n = 13 from normal term cesarean sections [not in labor]) in an organ explant system were stimulated with heat-killed Ureaplasma parvum, Gardanerella vaginalis, Escherichia coli, group B Streptococcus (GBS), or lipopolysaccharide (LPS). Cytokines (interleukin [IL]-1beta, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-alpha, and interferon-gamma) and PG (PGF(2alpha) and PGE(2)) concentrations were quantitated and compared.

RESULTS

LPS and E coli increased all cytokine and PG productions compared with controls. Cytokine profiles were similar after G vaginalis and GBS stimulation. G vaginalis increased PGE(2), whereas GBS increased PGF(2alpha). U parvum demonstrated the mildest response with only IL-10 and TNF-alpha concentrations being higher with no detectible effect on PGs.

CONCLUSION

Fetal membrane cytokine signatures of 4 different bacteria associated with PTB are distinct, suggesting that infection as a potential cause of PTB is not homogeneous in its presentation.

Antibiotic prophylaxis improves Ureaplasma-associated lung disease in suckling mice

Ureaplasma infection is associated with increased lung disease in high-risk neonates. Our goal was to determine the impact of antibiotic prophylaxis on Ureaplasma and oxygen-induced lung disease in newborn mice. In animal model development and prophylaxis experiments, pups were randomly assigned to either 0.8 or 0.21 inspired oxygen concentration [fraction of inspired oxygen (FiO2)] from 1 to 14 d of age and either Ureaplasma or 10 B media daily from 1 to 3 d. All pups were observed for growth and survival. Surviving pups had culture and PCR evaluated for blood, bronchoalveolar lavage, and lung, and lung weights, pathology, morphometry, histology, and immunohistochemistry were determined. In prophylaxis experiments, erythromycin, azithromycin, or normal saline was given for the first 3 d, and minimum inhibitory concentration and pharmacokinetics were determined. In model development, 0.8 FiO2 and Ureaplasma infection survival and growth were significantly decreased and lung edema and inflammation were significantly increased. In prophylaxis experiments, we observed significantly improved survival and growth with azithromycin versus normal saline controls, whereas erythromycin was not significantly different from controls, and decreased inflammatory response with azithromycin versus normal saline and erythromycin. In a neonatal mouse model of Ureaplasma and oxygen-induced lung disease, appropriate antibiotic prophylaxis improves survival and morbidity and decreases lung inflammation.

Prevalence and antibiotic susceptibility of Mycoplasma hominis and Ureaplasma urealyticum in pregnant women

BACKGROUND

Mycoplasma hominis and Ureaplasma urealyticum are important opportunistic pathogens implicated in urogenital infections and complicated pregnancy. We aimed to study the role of these pathogens in symptomatic and asymptomatic pregnant women and determine their clinical significance and antibiotic susceptibility.

METHODS

One hundred pregnant women were included in the study, 50 symptomatic patients and 50 asymptomatic controls. Duplicate endocervical samples were taken from each individual and analyzed using the Mycoplasma IST-2 kit and A7 agar medium. Antimicrobial susceptibility was tested against doxycycline, josamycin, ofloxacin, erythromycin, tetracycline, ciprofloxacin, azithromycin, clarithromycin, and pristinamycin using the Mycoplasma IST-2 kit.

RESULTS

Twelve symptomatic pregnant women had spontaneous abortions. Of these, eight (66.7%) cases had been colonized with M. hominis and/or U. urealyticum. Of the pregnant women infected with M. hominis and/or U. urealyticum, 40.7% delivered a low birth weight infant. M. hominis was successfully cultured in five women (5%) and U. urealyticum in 27 (27%). Among positive cultures, 15.6% and 84.4% of isolates were M. hominis and U. urealyticum, respectively. M. hominis and U. urealyticum were uniformly susceptible to doxycycline, tetracycline, and pristinamycin, which may be successfully used in the empirical therapy of infected individuals.

CONCLUSIONS

It can be concluded that genital colonization with M. hominis and U. urealyticum may predispose to spontaneous abortion and low birth weight.

Perinatal correlates of Ureaplasma urealyticum in placenta parenchyma of singleton pregnancies that end before 28 weeks of gestation

OBJECTIVES

The purpose of this work was to examine the relationship between Ureaplasma urealyticum in the placenta and perinatal outcomes in extreme preterm deliveries and to explore the influence of bacteria coinfection on perinatal outcomes in U urealyticum-positive placentas.

METHODS

Under sterile conditions, a piece of chorion from 866 singleton deliveries before 28 weeks' gestation was obtained and flash frozen. The tissue was later homogenized and cultured for Ureaplasma and bacteria. Placentas were also examined histologically. Maternal and neonatal data were obtained prospectively. Each infant had 3 sets of cranial ultrasound scans between days 1 to 4, 5 to 14, and between day 15 and 40th week postconceptional age. Cranial ultrasound findings were by consensus of 2 or 2 of 3 sonologists.

RESULTS

U urealyticum was recovered from 6% and bacteria from 47%; 47% of placentas had no bacteria detectable. Sixty-seven percent of Ureaplasma-positive placentas also harbored bacteria. Placentas that harbored U urealyticum only were more likely than sterile placentas to be associated with a higher prevalence of preterm labor and preterm premature rupture of membranes, as well as umbilical cord, fetal vessel, membrane, and parenchymal inflammation and to predict intraventricular hemorrhage and echolucent brain lesions. Placentas that harbored U urealyticum only were similar to placentas that harbored bacteria only. Recovery of U urealyticum and bacteria from same placenta did not enhance the differences between placentas with U urealyticum alone and sterile placentas. Recovery of U urealyticum only was not associated with a higher risk of death before day 7 of life.

CONCLUSIONS

The presence of U urealyticum in placental parenchyma before 28 weeks is associated with increased risk of preterm labor and delivery, higher risk of fetal and maternal inflammation, and increased risk of intraventricular hemorrhage and echolucent brain lesions but not of early neonatal death.

Role of Ureaplasma species in neonatal chronic lung disease: epidemiologic and experimental evidence

The contribution of Ureaplasma respiratory tract colonization to the pathogenesis of bronchopulmonary dysplasia in preterm infants has been debated for over 20 y. We review the current understanding of the role of inflammation in altered developmental signaling in the preterm lung and the evidence from human studies and experimental models that Ureaplasma-mediated inflammation produces the BPD phenotype. We propose that Ureaplasma infection initiated in utero and augmented postnatally by exposure to volutrauma and oxygen elicits a sustained, dysregulated inflammatory response in the immature lung that impairs alveolarization, and stimulates myofibroblast proliferation and excessive collagen and elastin deposition. Potential strategies to prevent or ameliorate the effects of Ureaplasma infection in utero and in the preterm lung are discussed.

Alternate phase variation in expression of two major surface membrane proteins (MBA and UU376) of Ureaplasma parvum serovar 3

Ureaplasma urealyticum and Ureaplasma parvum are commensals and pathogens of the human urogenital tract and of newborn infants. There are four distinct U. parvum serovars and 10 distinct U. urealyticum serovars. Both species possess a distinct immunodominant variable surface protein, the multiple banded antigen (MBA), which shows size variability among isolates as a result of changes in the number of C-terminal repeating units. Adjacent to the MBA gene (UU375) lies UU376, which was annotated as 'Ureaplasma-specific conserved hypothetical gene'. In four different strains of U. parvum serovar 3, we demonstrated expression of UU376 by Western blot analysis and phase variation between UU376, here designated Upvmp376 (Ureaplasma phase-variable membrane protein 376), and MBA after application of selective pressure with hyperimmune antisera directed against either protein. By Southern blot analysis, we found that the switch between MBA and Upvmp376 expression is associated with a DNA inversion event in which the nonrepetitive region of the MBA gene and its putative promoter region are opposed to either the repetitive region of MBA or UU376. We propose that in U. parvum serovar 3, and presumably in all U. parvum and U. urealyticum, an inversion event at specific sites effects an alternate ON/OFF switching of the genes UU375 and UU376.

Uncultivated bacteria as etiologic agents of intra-amniotic inflammation leading to preterm birth

Intra-amniotic infection and inflammation are major causes of preterm birth (PTB). However, intra-amniotic inflammation is often detected in the absence of infection. This may partly be due to the culturing methods employed in hospital laboratories, which are unable to detect the uncultivated species. In this study, intra-amniotic microbial infections associated with PTB were examined by both culture and 16S rRNA-based culture-independent methods and were corroborated by the presence of intra-amniotic inflammation. Amniotic fluid (AF) specimens from 46 pregnancies complicated by PTB and 16 asymptomatic women were analyzed. No bacterial DNA was amplified in AF collected from the asymptomatic women. Among the 46 samples associated with PTB, bacterial DNA was amplified from all (16/16) of the culture-positive samples and 17% (5/30) of the culture-negative samples. In the culture-positive group, additional species were detected in more than half (9/16) of the cases by PCR and clone analysis. Altogether, approximately two- thirds of the species detected by the culture-independent methods were not isolated by culture. They included both uncultivated and difficult-to-cultivate species, such as Fusobacterium nucleatum, Leptotrichia (Sneathia) spp., a Bergeyella sp., a Peptostreptococcus sp., Bacteroides spp., and a species of the order Clostridiales. To examine intra-amniotic inflammation, an AF proteomic fingerprint (mass-restricted score) was determined by surface-enhanced laser desorption ionization-time-of-flight mass spectrometry. Inflammation was detected in all five samples which were culture negative but PCR positive. Women who were PCR positive more often had elevated interleukin-6 levels in their AF, histological chorioamnionitis, and funisitis and delivered neonates with early-onset neonatal sepsis. Previously unrecognized, uncultivated, or difficult-to-cultivate species may play a key role in the initiation of PTB.

Correlations of selected vaginal cytokine levels with pregnancy-related traits in women with bacterial vaginosis and mycoplasmas

The aim of this study was to examine correlations between vaginal inflammatory cytokines (IL-1alpha, IL-1beta, IL-6 and IL-8) and pregnancy-related traits (gestational age, birth-weight, BMI, weight gain during pregnancy and vaginal pH). Differences in correlation coefficients were examined among bacterial vaginosis (BV) status and the presence or absence of mycoplasmas. A total of 105 women between the 22nd and 34th week of pregnancy were enrolled in this study. There was a strong negative correlation between IL-1alpha and weight gain during pregnancy (r=-0.877, p<0.001) and a strong positive correlation between IL-6 and BMI (r=0.670, p=0.024) in women with normal vaginal flora and mycoplasmas. These correlations were not present in women who had normal flora and no mycoplasmas. In women with BV and no mycoplasmas, there were significant correlations of gestational age with IL-6 (r=0.727, p=0.027) and IL-8 (r=0.689, p=0.040); however, these correlations were not significant in women with mycoplasmas. Our findings support the conclusion that correlations between inflammatory cytokines and pregnancy-related traits are dependent on context, suggesting that expression is labile. In particular, BMI and gestational age correlation differs depending on BV status and the presence or absence of BV-related mycoplasmas such as Mycoplasma hominis and Ureaplasma urealyticum.

Molecular detection of Ureaplasma urealyticum infection from clinical urogenital swabs

A simple nucleic acid amplification test (NAAT) was developed for detection of Ureaplasma urealyticum infection based on the PCR amplification of the urease gene (UU1/UU2 Test). DNA was extracted from urogenital swabs and a 225-bp long DNA fragment was amplified by PCR. NAAT was compared to the commercial amplification kit for sexually transmitted disease reference assay. The sensitivity and specificity of the UU1/UU2 Test were determined to be 100 and 98.9%, respectively. The overall prevalence rate in this group of patients was found to be about 236 per 1000 (283 and 166 per 1000 in females and males, respectively). These data demonstrate that UU1/UU2 Test is suitable for effective epidemiological screening and/or diagnostic practice.

The Alabama Preterm Birth Study: umbilical cord blood Ureaplasma urealyticum and Mycoplasma hominis cultures in very preterm newborn infants

OBJECTIVE

This study was undertaken to evaluate the frequency of umbilical cord blood infections with Ureaplasma urealyticum and Mycoplasma hominis in preterm 23- to 32-week births and to determine their association with various obstetric conditions, markers of placental inflammation, and newborn outcomes.

STUDY DESIGN

351 mother/infant dyads with deliveries between 23 and 32 weeks' gestational age who had cord blood cultures for U. urealyticum and M. hominis had their medical records abstracted, other placental cultures performed, cord interleukin-6 levels determined, placentas evaluated histologically, and infant outcomes determined.

RESULTS

U. urealyticum and/or M. hominis were present in 23% of cord blood cultures. Positive cultures were more common in infants of nonwhite women (27.9% vs 16.8%; P = .016), in women less than 20 years of age, in those undergoing a spontaneous compared to an indicated preterm delivery (34.7% vs 3.2%; P = .0001), and in those delivering at earlier gestational ages. Intrauterine infection and inflammation were more common among infants with a positive U. urealyticum and M. hominis culture as evidenced by placental cultures for these and other bacteria, elevated cord blood interleukin-6 levels, and placental histology. Infants with positive cord blood U. urealyticum and M. hominis cultures were more likely to have neonatal systemic inflammatory response syndrome (41.3% vs 25.7%; P = .007; adjusted odds ratio, 1.86; 1.08-3.21) and probably bronchopulmonary dysplasia (26.8% vs 10.1%; P = .0001; adjusted odds ratio 1.99; 0.91-4.37), but were not significantly different for other neonatal outcomes, including respiratory distress syndrome, intraventricular hemorrhage, or death.

CONCLUSION

U. urealyticum and M. hominis cord blood infections are far more common in spontaneous vs indicated preterm deliveries and are strongly associated with markers of acute placental inflammation. Positive cultures are associated with neonatal systemic inflammatory response syndrome and probably bronchopulmonary dysplasia.

Certain type of chronic lung disease of newborns is associated with Ureaplasma urealyticum infection in utero

BACKGROUND

Recent studies of chronic lung disease (CLD) of newborns emphasize the contribution of antenatal infection. However, the association of Ureaplasma urealyticum infection and CLD has been controversial. The purpose of the present paper was to determine whether U. urealyticum is associated with chorioamnionitis (CAM) and a certain type of CLD.

METHODS

One hundred and five infants <32 weeks of gestation who were admitted to the neonatal intensive care unit at Jichi Medical School Hospital, who underwent both histological and microbiological examinations and who survived to discharge were included. CAM was determined by histological examination. Placenta, gastric and tracheal aspirates, and nasopharyngeal swabs were cultured for Mycoplasma and other microorganisms. CLD was defined as oxygen needed at 28 days of age with symptoms of persistent respiratory distress and hazy or emphysematous and fibrous appearance upon X-ray. CLD was further divided into two subtypes according to the presence of antenatal infection.

RESULTS

CAM was associated with premature rupture of membrane (odds ratio [OR], 10.19; 95% confidence interval [CI]: 3.10-33.56), placental colonization of U. urealyticum (OR 6.73, 95%CI: 1.89-23.91), neonatal colonization of other microorganisms (OR 7.33, 95%CI: 1.22-44.13) and level of IgM (OR 1.06, 95%CI: 1.01-1.11). Comparisons between CLD and non-CLD patients showed that gestational age (OR 0.43, 95%CI: 0.30-0.61) and white blood cell count (WBC) at birth (OR 1.06, 95%CI: 1.01-1.11) were risk factors for CLD, while gestational age (OR 0.38, 95%CI: 0.23-0.64), neonatal colonization of U. urealyticum (OR 5.98, 95%CI: 1.17-30.6) and WBC (OR 1.08, 95%CI: 1.01-1.15) were independent risk factors for infection-related CLD compared with non-CLD. Within CLD, infection-related CLD was associated with neonatal colonization of U. urealyticum (OR 43.7, 95%CI: 2.84-673.8) and WBC (OR 1.27, 95%CI: 1.07-1.50).

CONCLUSIONS

Placental colonization of U. urealyticum was significantly related to CAM; and neonatal colonization of U. urealyticum and leukocytosis at birth were risk factors for infection-related CLD.

The role of Ureaplasma nucleoside monophosphate kinases in the synthesis of nucleoside triphosphates

Mollicutes are wall-less bacteria and cause various diseases in humans, animals and plants. They have the smallest genomes with low G + C content and lack many genes of DNA, RNA and protein precursor biosynthesis. Nucleoside diphosphate kinase (NDK), a house-keeping enzyme that plays a critical role in the synthesis of nucleic acids precursors, i.e. NTPs and dNTPs, is absent in all the Mollicutes genomes sequenced to date. Therefore, it would be of interest to know how Mollicutes synthesize dNTPs/NTPs without NDK. To answer this question, nucleoside monophosphate kinases (NMPKs) from Ureaplasma were studied regarding their role in the synthesis of NTPs/dNTPs. In this work, Ureaplasma adenylate kinase, cytidylate kinase, uridylate kinase and thymidylate kinase were cloned and expressed in Escherichia coli. The recombinant enzymes were purified and characterized. These NMPKs are base specific, as indicated by their names, and capable of converting (d)NMPs directly to (d)NTPs. The catalytic rates of (d)NTPs and (d)NDP synthesis by these NMPKs were determined using tritium-labelled (d)NMPs, and the rates for (d)NDP synthesis, in general, were much higher (up to 100-fold) than that of (d)NTP. Equilibrium studies with adenylate kinase suggested that the rates of NTPs/dNTPs synthesis by NMPKs in vivo are probably regulated by the levels of (d)NMPs. These results strongly indicate that NMPKs could substitute the NDK function in vivo.

Characterization of the Macrophage-Stimulating Activity from Ureaplasma urealyticum

PROBLEM

Intra-amniotic infection is the most common cause of preterm labor. Infections are thought to cause preterm labor by increasing the production of proinflammatory cytokines at the maternal-fetal interface. Experiments with cell culture and animal models have indicated that bacterial lipopolysaccharide (LPS) increases the production of proinflammatory cytokines in reproductive tissues. The majority of intrauterine infections, however, are associated with Ureaplasma urealyticum, which does not contain LPS. Therefore, we performed a series of experiments to understand better the bacterial factor(s) that are responsible for the proinflammatory effects of U. urealyticum.

METHOD OF STUDY

U. urealyticum was cultivated in 3-4 L 10B broth, harvested by centrifugation, washed with saline and frozen at -85 degrees C until use. Cells were then extracted with Triton X-114 and the macrophage-stimulating activity (MSA) of the preparations was studied by evaluating their ability to stimulate tumor necrosis factor-alpha production by a monocytic cell line (THP-1 cells). Additional studies involved testing the sensitivity of the detergent extracts to heating, alkaline hydrolysis and proteinase K digestion. Interaction of Triton X-114 extracts with Toll-like receptor (TLR)-2 and TLR-4 was evaluated using cell lines transfected with one of these receptors, CD14 and a reporter gene.

RESULTS

Extraction of U. urealyticum with Triton X-114 demonstrated that the MSA preferentially partitioned to the detergent phase. The MSA of the detergent extracts was abrogated by proteinase K digestion or alkaline hydrolysis but only partially inhibited by heating. Further studies suggested that the detergent extracts could activate both TLR-2 and TLR-4.

CONCLUSION

These experiments suggest that the MSA of U. urealyticum is lipophilic, sensitive to alkaline hydrolysis and proteinase K digestion, partially sensitive to heating. These properties are consistent with the activity being due to a lipoprotein. Unlike other Mycoplasma species, the MSA of U. urealyticum appears to interact with both TLR-2 and TLR-4. Purification of the molecule(s) that regulate this activity may provide good therapeutic targets for anti-inflammatory strategies to prevent preterm labor caused by intrauterine infection with U. urealyticum.

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.

The Respiratory System

One of the most critical events of birth is the conversion of the fluid-filled lung, unimportant to fetal intrauterine existence, into a hollow organ distended with air and capable of gaseous exchange sufficient to support life. Indeed, it has been argued that the major determinant of perinatal survival is respiratory function (Wigglesworth and Desai 1982).

The failure to make this conversion adequately may lead, directly or indirectly, to infant death, and the pathologist often needs to assess the contribution made by respiratory inadequacy to the sequence of events leading to death. In the preterm infant, problems are mainly related to pulmonary immaturity and associated therapy. In the mature infant, birth asphyxia primarily results in cerebral damage but can engender significant respiratory complications when associated with aspiration of meconium. Even in stillbirths, where primary pulmonary pathology is rarely a cause of death, lung pathology may provide clues to antecedent events. Poor lung growth and maturation may point to the presence of pathology elsewhere. Consequently, adequate pathological investigation of the fetal or infant respiratory system is critical in any perinatal autopsy.

Management of preterm prelabour rupture of membranes: an audit. How do the results compare with clinical practice guidelines?

BACKGROUND

Preterm prelabour rupture of membranes is a common clinical event. It is associated with infection in approximately 50% of cases. Clinical practice guidelines have been developed at the Royal Women's Hospital, Melbourne, Australia for investigation and management of this condition.

AIM

To perform an audit of management of women presenting with this diagnosis and assess how inpatient management compares with the Hospital's current clinical practice guideline and how the clinical practice guideline compares with the evidence in the literature.

METHODS

Retrospective audit over a 3-month period collecting data on maternal age, gestation, microbiological results, other investigations, pharmacological treatment and outcome.

RESULTS

All the 56 women admitted for this reason received at least one dose of antibiotic, most commonly erythromycin. More than two thirds of patients had the antibiotic changed at least once during their admission. Ten patients were prescribed intravenous antibiotics without a clear indication. Sixty-four percent received steroids for lung maturation of the neonate and 30% received tocolysis with nifedipine. Almost two thirds of patients delivered within 7 days and there were four neonatal deaths.

CONCLUSION

In general management of women with premature rupture of membranes is in keeping with the current clinical practice guideline at the Royal Women's Hospital although antibiotic prescribing and management of Group B streptococcus colonisation could be improved. In addition, routine measurement of C reactive protein should cease. The current clinical practice guideline should be modified to reflect the current evidence in the literature.

Amniotic fluid intercellular adhesion molecule-1 is a marker for Ureaplasma infection in women with preterm labor

OBJECTIVE

The objective of the study was to determine the amniotic fluid soluble intercellular adhesion molecule-1 concentrations in women with preterm labor in relation to intra-amniotic infection.

STUDY DESIGN

Amniotic fluids from 125 women with preterm labor (78 with preterm delivery and 47 with term deliveries) were examined for both soluble intercellular adhesion molecule-1 concentrations and intra-amniotic infection with Ureaplasma species. A chi2 test, or Fisher's exact test, when appropriate, was used for statistical analysis.

RESULTS

In the preterm delivery group, 45% (35 of 78) had intra-amniotic infection with Ureaplasma species, compared with 19% (9 of 47) in the term delivery group (P = .004). In women with intra-amniotic infection, 26% (9 of 38) had soluble intercellular adhesion molecule-1 levels above 1290 ng/ml. Only 2.3% (1 of 43) in the preterm delivery group without intra-amniotic infection attained this diagnostic level (P = .004). In contrast, there was no significant difference in soluble intercellular adhesion molecule-1 levels between those with or without intra-amniotic infection in the term delivery group.

CONCLUSION

Amniotic fluid soluble intercellular adhesion molecule-1 concentrations exceeding 1290 ng/ml can be used as a marker for intra-amniotic infection with Ureaplasma in patients with preterm labor.

Trends in the rates of resistance of Ureaplasma urealyticum to antibiotics and identification of the mutation site in the quinolone resistance-determining region in Chinese patients

The resistance of Ureaplasma urealyticum to antibacterials, isolated from 804 patients from the outpatient clinic of the Sir Run Run Shaw Hospital Hangzhou, China, from March to June over six consecutive years (1999-2004) was reviewed. The quinolone resistance-determining region of six strains of U. urealyticum was analyzed. The level of resistance to doxycycline, josamycin, tetracycline, azithromycin, clarithromycin and pristinamycin was below 20% and did not change during the study period. The rate of resistance to fluoroquinolones (ofloxacin, ciprofloxacin) was much greater than these (>50%) and has increased since 1999. The rate of resistance to Erythromycin decreased from 63.9% in 1999 to about 20% from 2000 onwards. The widespread use of fluoroquinolones had led to high resistance rates in U. urealyticum and the emergence of quinolone resistance. Analysis of the gene sequence of topoisomerase IV and DNA gyrase suggested a role for the topoisomerase IV ParE subunit in fluoroquinolone-resistant U. urealyticum.

The significance of Ureaplasma urealyticum as a pathogenic agent in the paediatric population

PURPOSE OF REVIEW

Ureaplasma urealyticum is a frequent commensal in the lower genital tract of sexually active women. It may be transmitted perinatally from the colonized mother to her offspring, often resulting in prematurity and neonatal disease. The microorganism also sustains a causative role for infectious diseases in older children.

RECENT FINDINGS

U. urealyticum infection can be diagnosed by culture, polymerase chain reaction, and the detection of specific antibodies. Neonatal infection has been implicated in various pathological conditions including pneumonia, chronic lung disease, central nervous system disorders, sepsis, osteomyelitis and even death. Older children may present with wheezing, pneumonitis, pertussis-like syndrome and different forms of arthritis. Large well-designed trials have demonstrated that the regular administration of antibiotics to vaginally colonized women are not beneficial in terms of preventing preterm labour. Macrolide-containing antibiotic regimens are, however, recommended for preterm premature rupture of the membranes. Erythromycin treatment of ureaplasma respiratory colonized premature infants shows no reduction in the incidence of chronic lung disease. Treatment of central nervous system infections, sepsis and arthritides includes tetracyclines, fluoroquinolones and anti-inflammatory agents, respectively.

SUMMARY

This review covers recent evidence concerning the role of U. urealyticum as a pathogen during childhood. It also includes an evaluation of contemporary diagnostic techniques and optimal therapeutic approaches.

Value of Endocervical Ureaplasma Species Colonization as a Marker of Preterm Delivery

AIMS

To study the predictive value for preterm delivery of colonization of the cervix and vagina by ureaplasmas and other potentially pathogenic microorganisms.

METHODS

Prospective analysis of a study group of 200 pregnant women with preterm labor and intact membranes, and a control group of 50 pregnant women. The subjects in both groups were between 24 and 34 weeks of gestation. Ureaplasma spp. and Mycoplasma hominis endocervical cultures were performed for both groups.

RESULTS

In the study group, 70 of the women delivered preterm, and all women in the control group carried their pregnancies to full term. Cervical cultures for Ureaplasma spp. were positive in 119 women, and were isolated more frequently in the study group (51.5%) than in the control group (32%), and more frequently in subjects in the study group who delivered preterm (65%) than in those who had a full-term delivery (45%), differences that were statistically significant.

CONCLUSION

Detection of Ureaplasma spp. in the endocervix has a statistically significant relationship to preterm labor (p = 0.03) and preterm delivery (p = 0.02) in pregnant women with preterm labor and intact membranes.

Association between preterm birth and vaginal colonization by mycoplasmas in early pregnancy

To examine the association between colonization by two newly classified species of genital ureaplasmas (Ureaplasma parvum and U. urealyticum) in early pregnancy and subsequent late abortion or preterm birth at <34 weeks of gestation, four species of genital mycoplasmas--Mycoplasma genitalium, M. hominis, U. parvum, and U. urealyticum--as well as Chlamydia trachomatis and Neisseria gonorrhoeae were examined by PCR-based methods in a prospective cohort study of 877 women with singleton pregnancies at <11 weeks of gestation. Antibiotics were used only in cases in which C. trachomatis and/or N. gonorrhoeae was detected. Multivariate logistic-regression analysis was used to assess independent risk factors after taking maternal low body weight and past history of preterm birth into account. M. genitalium, M. hominis, U. parvum, U. urealyticum, C. trachomatis, and N. gonorrhoeae were detected in 0.8%, 11.2%, 52.0%, 8.7%, 3.2%, and 0.1% of these 877 women, respectively. Twenty-one (2.4%) women experienced late abortion or preterm birth at <34 weeks of gestation. Three factors-detection of U. parvum in the vagina (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.1 to 8.5); use of antibiotics, such as penicillin and cefatrizine, for incidental inflammatory complications before 22 weeks of gestation (OR, 4.2; 95% CI, 1.6 to 10.0); and past history of preterm birth (OR, 10.4; 95% CI, 2.7 to 40.5)-were independently associated with late abortion and preterm birth. In conclusion, vaginal colonization with U. parvum, but not U. urealyticum, is associated with late abortion or early preterm birth.

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.

Critical appraisal of the role of Ureaplasma in the development of bronchopulmonary dysplasia with metaanalytic techniques

BACKGROUND

Controversy exists over whether or not Ureaplasma colonization or infection of the respiratory tract contributes to the development of bronchopulmonary dysplasia (BPD). Because BPD is a major cause of morbidity and mortality in preterm infants and a potential therapeutic intervention with antimicrobials is possible, we sought to evaluate and critique the current medical literature and to document the reported association between Ureaplasma and BPD.

METHODS

We analyzed all peer-reviewed articles and previous reviews including cross-references that reported Ureaplasma respiratory tract colonization or infection and development of BPD in neonates published from January 1966 to December 2004. Inclusion criteria included a cohort limited to all neonatal intensive care unit admissions or all colonized infants, articles that did not define a numerator and a denominator for BPD and Ureaplasma or that included patients from other reports were excluded from the analysis. We evaluated BPD at 28 postnatal days (BPD28) or 36 weeks post-menstrual age (BPD36).

RESULTS

Twenty-three studies with an aggregate of 2216 infants reported BPD28, and 8 studies with 751 infants reported BPD36. Although there was significant association between Ureaplasma colonization and both BPD28 and BPD36, there was substantial heterogeneity (Q test statistic, P < 0.01). We therefore focused on describing the study characteristics associated with an increased relative proportion of BPD. The greatest contribution to effect was from the studies enrolling fewer than 100 infants.

CONCLUSION

Ureaplasma colonization is associated with higher reported rates of BPD, but the greatest reported effect is seen in small studies; reporting bias may be partially responsible for this effect.

Increased intrauterine frequency of Ureaplasma urealyticum in women with preterm labor and preterm premature rupture of the membranes and subsequent cesarean delivery

OBJECTIVE

The purpose of this study was to evaluate the prevalence of microbial invasion of the amniotic cavity at the time of preterm cesarean delivery for therapy-resistant preterm labor or preterm premature rupture of membranes, which are events that commonly are induced by infection, and to compare this group of patients with a group of patients who underwent preterm cesarean delivery for indications other than preterm labor or preterm premature rupture of membranes.

STUDY DESIGN

We studied 207 consecutive women between 23 and 34 weeks of gestation who underwent cesarean delivery. These patients were divided into 3 groups according to the indication for cesarean delivery: patients with preterm labor (group 1), patients with preterm premature rupture of membranes (group 2), and patients with other indications (group 3). In the course of the surgical procedure, amniotic fluid, amniotic membrane, and placental tissue specimens were collected for the detection of pathogens.

RESULTS

Ureaplasma urealyticum was detected in 43.9% (58/132) of the patients of groups 1 and 2, with no significant difference between these 2 subgroups. In group 3, which served as the comparison group, Ureaplasma urealyticum was isolated in only 2.7% (2/75) of the patients. Ureaplasma urealyticum as a single pathogen was more frequent than all obligate pathogens together (43.9% vs 39.3%).

CONCLUSION

Our results provide evidence for an association between intrauterine colonization with Ureaplasma urealyticum and both therapy-resistant preterm labor and preterm premature rupture of membranes.

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 genital mycoplasmosis causes increased levels of mRNA for IL-6 and TNF-alpha in the placenta

PROBLEM

Previous studies with animal models have shown that injection of lipopolysaccharide (LPS) results in fetal loss and increases production of proinflammatory cytokines at the maternal-fetal interface. Most intrauterine infections, however, are associated with Ureaplasma urealyticum, a microorganism that lacks a cell wall and therefore does not contain LPS. Previous work in our laboratory with an animal model for genital infection with a similar organism, Mycoplasma pulmonis, revealed that widespread infection in maternal and fetal tissues can be experimentally induced with minimal manipulation of the animal. For this project, we tested the hypothesis that administration of the organism by a hematogenous route at gestational day (gd) 14 would result in increased tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 production by the placenta.

STUDY DESIGN

Timed-pregnant, Sprague-Dawley rats were anesthetized on gd 14 and 10(7) CFU of M. pulmonis strain X1048 or an equivalent volume of sterile medium was injected into the heart. Rats were necropsied on gd 18 or 21, and ex vivo production of TNF-alpha and IL-6 was evaluated from six randomly selected placentas from each litter. The remaining placentas were harvested and either snap-frozen or placed in formalin. Frozen placentas were processed for real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of TNF-alpha and IL-6 mRNA. Formalin-fixed placentas were sectioned and stained with hematoxylin and eosin for lesion analysis.

RESULTS

Concentrations of TNF-alpha but not IL-6 were significantly higher in conditioned medium from placentas harvested from infected dams at gd 21. Levels of mRNA for IL-6 and TNF-alpha, however, were increased by M. pulmonis at gd 18 and 21. Analysis of gd 21 placentas by light microscopy revealed that significant histological chorioamnionitis was present in infected animals with accumulations of neutrophils in the capsular decidua.

CONCLUSION

These data indicate that experimental infection with M. pulmonis causes histological chorioamnionitis, elevated mRNA levels of TNF-alpha and IL-6 in placental tissues, and the secretion of TNF-alpha by the placenta during late gestation.

Ureaplasma urealyticum, Mycoplasma hominis et pathologiesnéonatales : Données personnelles et revue de la littérature

Ureaplasma urealyticum and Mycoplasma hominis colonized 20-40% of newborns and are more frequent in premature. They are responsible for localized infections such as pleural effusion, pneumopathy, adenopathy, abscess or systemic sepsis. An important hyperleukocytosis is often associated with pulmonary infections. Their responsibility, as pathogen agents, is questionable in some non bacterial meningitis. There is large controversy for their role as cofactor, in chronic lung disease (bronchopulmonary dysplasia) and periventricular leukomalacia, because of a too low number of newborns in prospective trials. Genital mycoplamas are resistant to beta lactamines. Macrolides have a good sensitivity, particularly josamycine, but Mycoplasma hominis is resistant to erythromycin. For systemic sepsis, fluoroquinolones such as ciprofloxacine have less deleterious effects than IV erythromycin.

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.

Comparison of the Mycoplasma Duo test with PCR for detection of ureaplasma species in endotracheal aspirates from premature infants

We compared the Mycoplasma Duo kit (Sanofi Diagnostics Pasteur) with PCR for detection of Ureaplasma spp. in endotracheal aspirates from 60 premature neonates. The overall agreement between the two tests was 96%. The Mycoplasma Duo assay is a useful alternative to culture and PCR for detection of neonatal Ureaplasma infection.

Ureaplasma urealyticum binds mannose-binding lectin

Mannose-binding C-type lectin (MBL) is an important component of innate immunity in mammals. Mannose-binding lectin (MBL), an acute phase protein, acts as an opsonin for phagocytosis and also activates the mannan-binding lectin complement pathway. It may play a particularly significant role during infancy before adequate specific protection can be provided by the adaptive immune system. Ureaplasma urealyticum has been linked to several diseases including pneumonia and chronic lung disease (CLD) in premature infants. We therefore investigated the ability of U. urealyticum to bind MBL. A guinea pig IgG anti-rabbit-MBL antiserum was produced. An immunoblot (dot-blot) assay done on nitrocellulose membrane determined that the anti-MBL antibody had specificity against both rabbit and human MBL. Pure cultures of U. urealyticum, serotype 3, were used to make slide preparations. The slides containing the organisms were then incubated with nonimmune rabbit serum containing MBL. Ureaplasma was shown to bind rabbit MBL with an immunocytochemical assay using the guinea pig IgG anti-rabbit MBL antiserum. Horseradish peroxidase (HRP)-labeled anti-guinea pig IgG was used to localize the reaction. The anti-MBL antiserum was also used in an immunocytochemical assay to localize U. urealyticum in histological sections of lungs from mice specifically infected with this organism. The same method also indicated binding of MBL by ureaplasma in human lung tissue obtained at autopsy from culture positive infants. Our results demonstrate that ureaplasma has the capacity to bind MBL. The absence of MBL may play a role in the predisposition of diseases related to this organism.

Rat strains differ in susceptibility to maternal and fetal infection with Mycoplasma pulmonis

PROBLEM

Vaginally infected Sprague-Dawley (SD) rats are more susceptible to adverse pregnancy outcomes than Wistar (WIS) rats. We postulated that SD rats have enhanced hematogenous spread of Mycoplasma pulmonis to fetal tissues.

METHOD OF STUDY

WIS and SD dams were infected intravenously with 10(7), 10(6), and 10(5) colony-forming units of M. pulmonis at gestation day 14. Dams and six randomly selected fetuses were cultured at days 15, 16, 17, and 18 of gestation.

RESULTS

In the high-dose group, 100% of fetuses were colonized regardless of rat strain. Significantly higher numbers of M. pulmonis were isolated from placenta (low dose, P < 0.0001; medium dose, P < 0.024; high dose, P < 0.0001), amniotic fluid (low dose, P < 0.003; medium dose, P < 0.017), and fetuses (low dose, P < 0.0011) of SD rats. Spread of M. pulmonis to the amniotic fluid and fetus occurred 1 day earlier in SD rats.

CONCLUSIONS

The difference in susceptibility between the two rat strains cannot be explained by hematogenous spread alone. The relative resistance to adverse pregnancy outcomes in WIS rats may be a function of a more robust innate immune system. These rat strains may represent an animal model to address host resistance factors to intrauterine infection.

Maternal genital colonization with Ureaplasma urealyticum promotes preterm delivery: association of the respiratory colonization of premature infants with chronic lung disease and increased mortality

BACKGROUND

Infection of the chorioamnion with Ureaplasma urealyticum has been associated with low birth weight. Respiratory tract colonization in preterm infants has been associated with the development of chronic lung disease (CLD). The purpose of the present study was to determine the frequency of colonization of the mother's vagina and the preterm infant's respiratory tract and to associate U. urealyticum with premature birth and with development of CLD in the newborn.

METHODS

The present prospective study involved 126 mothers with preterm delivery and 125 mothers with full-term delivery, as well as their offspring. Vaginal secretion specimens were obtained from each mother before delivery. Rhinopharyngeal secretion or tracheal lavage specimens were collected after the birth of each premature and full-term infant and then periodically during hospitalization.

RESULTS

Vaginal Ureaplasma colonization occurred among 36.5% of mothers with preterm delivery and among 38% of mothers with full-term delivery. The rate of vertical transmission was 33% and 17% for mothers with preterm delivery and mothers with full-term delivery, respectively. The transmission rate for infants, according to birth weight, was as follows: 60%, for infants with a birth weight of <1000 g; 50%, for infants with a birth weight of 1000-1500 g; and 15.3%, for infants with a birth weight of > or =1500 g (P=.001). The median gestational age of preterm infants born to colonized mothers was 28.5 weeks, and that of preterm infants born to noncolonized mothers was 32 weeks (P<.0001). The median birth weight of colonized preterm infants was 1135 g, and that of noncolonized infants was 1670 g (P<.0001). Twenty-four percent of preterm infants and 10% of full-term infants were colonized with U. urealyticum. Of colonized preterm infants, 27% developed CLD, compared with 9% of noncolonized infants (P=.03). Mortality was significantly higher among colonized preterm infants (P=.003).

CONCLUSIONS

The rate of vertical transmission is highest among preterm infants with a birth weight of <1500 g. Vaginal colonization with Ureaplasma organisms is associated with premature delivery. Colonization of the respiratory tract of infants is associated with the development of CLD and with increased mortality.

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.

Infection with Ureaplasma urealyticum: is there a specific clinical and radiological course in the preterm infant?

BACKGROUND

Despite having mild early respiratory disease, many preterm babies develop chronic lung disease (CLD). Intrauterine infection with Ureaplasma urealyticum has been associated with preterm labour and CLD.

OBJECTIVE

To test the hypothesis that infection with U urealyticum results in a specific clinical and radiological picture in the first 10 days of life.

METHODS

Retrospective study of 60 ventilated babies < 30 weeks gestation, who had tracheal secretions tested for U urealyticum. Placental histology was reviewed by a paediatric pathologist for signs of chorioamnionitis. Chest radiographs were independently reviewed by two paediatric radiologists according to previously agreed criteria. All reviewers were blinded to the infection status of the babies.

RESULTS

Twenty five babies were U urealyticum positive. These were more likely to experience chorioamnionitis (p = 0.004), premature rupture of membranes (p = 0.01), and spontaneous vaginal delivery (p = 0.09). U urealyticum positive babies had fewer signs of respiratory distress syndrome on early chest radiographs (p = 0.038), and they could be weaned from their ventilation settings (fraction of inspired oxygen (FIO(2)) and mean airway pressure) more quickly in the first few days. Subsequently U urealyticum positive babies deteriorated clinically and radiologically. More often they required ventilation to be restarted (p = 0.051), a higher proportion being ventilated on day 10 (p = 0.027) with higher FIO(2) (p = 0.001) and mean airway pressure (p = 0.002). Their chest radiographs showed more emphysematous changes as early as day 5 (p = 0.045), with a pronounced difference by day 10 (p = 0.009).

CONCLUSIONS

Preterm ventilated babies with U urealyticum in their tracheal secretions have a different clinical and radiological course, with less acute lung disease but early onset of CLD, compared with those with negative cultures.

[Genital mycoplasmas]

The mycoplasmas frequently isolated in genital tract, and potentially pathogenic, are M. hominis, U. urealyticum and M. genitalium. M. hominis and U. urealyticum are very frequent in the vaginal tract and they can be, according to circumstances, either commensal or pathogenic. M. hominis and/or U. urealyticum, have been considered as responsible for many types of genital infectious diseases (such as cervicitis, pelvis inflammatory disease), for infertility, obstetrical pathologies (premature delivery, premature rupture of membranes, chorio-amniotitis) and neonatal infections. Yet, most of the time, their actual responsibility has not been conclusively proven. Published data lack indisputable conclusions and in many fields, doubts still exist whether these mycoplasmas are pathogens or mere co-factors associated with genital infections. On the other hand, M. genitalium has been much less studied but it seems to be an unquestionable pathogen of genital tract; new studies will be necessary so that one has a better understanding of the pathologies it can induce.

Molecular characterization of thymidine kinase from Ureaplasma urealyticum: nucleoside analogues as potent inhibitors of mycoplasma growth

Ureaplasma urealyticum (U. urealyticum), belonging to the class Mollicutes, is a human pathogen colonizing the urogenital tract and causes among other things respiratory diseases in premature infants. We have studied the salvage of pyrimidine deoxynucleosides in U. urealyticum and cloned a key salvage enzyme, thymidine kinase (TK) from U. urealyticum. Recombinant Uu-TK was expressed in E. coli, purified and characterized with regards to substrate specificity and feedback inhibition. Uu-TK efficiently phosphorylated thymidine (dThd) and deoxyuridine (dUrd) as well as a number of pyrimidine nucleoside analogues. All natural ribonucleoside/deoxyribonucleoside triphosphates, except dTTP, served as phosphate donors, while dTTP was a feedback inhibitor. The level of Uu-TK activity in U. urealyticum extracts increased upon addition of dUrd to the growth medium. Fluoropyrimidine nucleosides inhibited U. urealyticum and M. pneumoniae growth and this inhibitory effect could be reversed by addition of dThd, dUrd or deoxytetrahydrouridine to the growth medium. Thus, the mechanism of inhibition was most likely the depletion of dTTP, either via a blocked thymidine kinase reaction and/or thymidylate synthesis step and these metabolic reactions should be suitable targets for antimycoplasma chemotherapy.

Antibiotics for ureaplasma in the vagina in pregnancy

BACKGROUND

Preterm birth is a significant obstetric problem in high-income countries. Genital infection including ureaplasmas are suspected of playing a role in preterm birth and preterm rupture of the membranes. Antibiotics are used to treat women with preterm prelabour rupture of the membranes and results in prolongation of pregnancy and lowers the risks of maternal and neonatal infection. However, antibiotics may be beneficial earlier in pregnancy to eradicate potentially causative agents.

OBJECTIVES

The objective of this review is to assess whether antibiotic treatment of pregnant women with ureaplasma in the vagina reduces the incidence of preterm birth and other adverse pregnancy outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (April 2003).

SELECTION CRITERIA

All randomised controlled trials that compared any antibiotic regimen with placebo or no treatment in pregnant women with ureaplasma detected in the vagina.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed eligibility and trial quality and extracted data.

MAIN RESULTS

One trial involving 1071 women was included. Of these, 644 randomly received antibiotic treatment (174 erythromycin estolate, 224 erythromycin sterate, and 246 clindamycin hydrochloride) and 427 received placebo. This trial did not report data on preterm birth. Incidence of low birthweight less than 2500 grams was only evaluated for erythromycin (combined) (n = 398 ) compared to placebo (n = 427) and there was no statistically significant difference between those treated and those not treated (relative risk (RR) 0.70, 95% confidence interval (CI) 0.46 to 1.07). In regards to side-effects sufficient to stop treatment, data were available for all women, and there were no statistically significant differences between any antibiotic (combined) and the placebo group (RR 1.25, 95% CI 0.85 to 1.85).

REVIEWER'S CONCLUSIONS

There is insufficient evidence to show whether giving antibiotics to women with ureaplasma in the vagina will prevent preterm birth.

The clinical significance of detecting Ureaplasma urealyticum by the polymerase chain reaction in the amniotic fluid of patients with preterm labor

OBJECTIVE

This study was undertaken to determine the clinical significance of a detection of Ureaplasma urealyticum by using the polymerase chain reaction (PCR) in the amniotic fluid of patients with preterm labor and intact membranes.

STUDY DESIGN

Amniocentesis was performed in 257 patients with preterm labor and intact membranes. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as genital mycoplasmas. U urealyticum was detected by PCR using specific primers. Patients were divided into 3 groups according to the results of amniotic fluid culture and PCR for U urealyticum: those with a negative culture and negative PCR (n=228), those with a negative culture but positive PCR (n=6), and those with a positive culture regardless of the results of PCR (n=23).

RESULTS

The prevalence of positive amniotic fluid culture was 9% (23 of 257). U urealyticum was detected by PCR in 6% (15 of 254) of cases. Of the 15 cases with positive PCR for U urealyticum, amniotic fluid culture was negative in 40% (6 of 15). Patients with a negative culture but positive PCR for U urealyticum had significantly shorter median amniocentesis-to-delivery interval and higher amniotic fluid interleukin-6 and white blood cell count than those with a negative amniotic fluid culture and negative PCR (P<.01 for each). Patients with a positive PCR for U urealyticum but a negative amniotic fluid culture had a higher rate of significant neonatal morbidity than those with a negative culture and negative PCR (P<.05). However, no significant differences in perinatal outcome were observed between patients with a negative culture but positive PCR and those with a positive amniotic fluid culture.

CONCLUSION

Patients with preterm labor and a positive PCR for U urealyticum but negative amniotic fluid culture are at risk for impending preterm delivery and adverse perinatal outcome.

Ureaplasma parvum and Ureaplasma urealyticum are detected in semen after washing before assisted reproductive technology procedures

OBJECTIVE

To investigate the prevalence of ureaplasmas in semen and washed semen and to explore their effect on semen andrology variables.

DESIGN

Prospective study.

SETTING

In vitro fertilization (IVF) unit of a private hospital.

PATIENT(S)

Three hundred forty-three men participating in an assisted reproductive technology (ART) treatment cycle.

MAIN OUTCOME MEASURE(S)

The prevalence of ureaplasmas in semen and washed semen tested by culture, polymerase chain reaction assays, and indirect immunofluorescent antibody assays.

RESULT(S)

Ureaplasmas were detected in 73 of 343 (22%) semen samples and 29 of 343 (8.5%) washed semen samples. Ureaplasmas adherent to the surface of spermatozoa were demonstrated by indirect immunofluorescent antibody testing. Ureplasma parvum serovar 6 (36.6%) and U. urealyticum (30%) were the most prevalent isolates in washed semen. A comparison of the semen andrology variables of washed semen ureaplasma positive and negative groups demonstrated a lower proportion of nonmotile sperm in men ureaplasma positive for washed semen.

CONCLUSION(S)

Ureaplasmas are not always removed from semen by a standard ART washing procedure and can remain adherent to the surface of spermatozoa.

Ureaplasma in lung. 1. Localization by in situ hybridization in a mouse model

Ureaplasma urealyticum is a common inhabitant of mucosal surfaces but is also associated with a higher incidence of pneumonia and bronchopulmonary dysplasia in preterm infants. Culture and polymerase chain reaction demonstrate high isolation rates of ureaplasma in clinical specimens documenting their presence but do not associate the organism directly with the diseased tissue. In this study, lung tissue samples from newborn mice inoculated intranasally with U. urealyticum were used to develop an in situ hybridization (ISH) test for the organism. In situ hybridization allows the localization of gene expression for visualization within the context of tissue morphology. New techniques which use biotinyl-tyramide based signal amplification have been able to greatly enhance the sensitivity of ISH. Using the Dako GenPoint Catalyzed Signal Amplification system to detect a biotinylated DNA probe specific for an internal nucleotide sequence within the urease gene of U. urealyticum, the organism was detected within the infected murine lung tissues. Electron microscopy was used to verify the presence of the organisms in the positive ISH areas. The ISH procedure developed in this study can be used to analyze the presence of ureaplasma in human neonatal lung tissue with the corresponding histopathology.

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.