Placental features of chorioamnionitis colonized with Ureaplasma species in preterm delivery

Identification of an endonuclease and N6-adenine methyltransferase from Ureaplasma parvum SV3F4 strain

Here, we report a novel endonuclease and N6-adenine DNA methyltransferase (m6A methyltransferase) in the Ureaplasma parvum SV3F4 strain. Our previous study found that the SV3F4 strain carries 17 unique genes, which are not encoded in the two previously reported U. parvum serovar 3 strain, OMC-P162 and ATCC 700970. Of these 17 unique genes, UP3_c0261 and UP3_c0262, were originally annotated as encoding hypothetical proteins. Comparative genomics analyses more recently indicated they encode a Type II restriction endonuclease and an m6A methyltransferase, respectively. The UP3_c0261 and UP3_c0262 genes were individually expressed and purified in Escherichia coli. The UP3_c0261 recombinant protein showed endonuclease activity on the pT7Blue vector, recognizing and cleaving a GTNAC motif, resulting in a 5 base 5' extension. The UP3_c0261 protein digested a polymerase chain reaction (PCR) product harboring the GTNAC motif. The endonuclease UP3_c0261 was designated as UpaF4I. Treatment of the PCR product with the recombinant protein UP3_c0262 completely blocked the restriction enzyme activity of UpaF4I. Analysis of the treated PCR product harboring a modified nucleotide by UP3_c0262 with HPLC-MS/MS and MS/MS showed that UP3_c0262 was an m6A methyltransferase containing a methylated A residue in both DNA strands of the GTNAC motif. Whole genome methylation analysis of SV3F4 showed that 99.9 % of the GTNAC motif was m6A modified. These results suggest the UP3_c0261 and UP3_c0262 genes may act as a novel Type II restriction-modification system in the Ureaplasma SV3F4 strain.

Microbiological investigation of pregnancies following vaginal radical trachelectomy using 16S rRNA sequencing of FFPE placental specimens

This study examined the risk of intrauterine infection associated with radical trachelectomy (RT) in early-stage cervical cancer patients. This procedure preserves fertility but is linked to increased risk of intrauterine infection due to cervical defects during pregnancy. DNA was extracted from the formalin-fixed paraffin-embedded (FFPE) placental specimens of 23 pregnant post-RT patients and 16S rRNA gene sequencing was used for bacterial identification. The prevalence of Lactobacillus crispatus and Burkholderia stabilis was significantly higher in the non-chorioamnionitis group. In contrast, alpha diversity analysis using the PD index showed significantly higher diversity in the chorioamnionitis group (P = 0.04). The demonstrated relationship between chorioamnionitis and microbial diversity affirms the importance of controlling the genital bacterial flora in pregnancies following RT.

Prevalence of genital Mycoplasma in pregnancies with shortened cervix

OBJECTIVE

To determine whether colonisation with genital Mycoplasma species (spp.) in patients presenting with a shortened cervix before 34th week of pregnancy is associated with preterm birth.

METHODS

The collection of this retrospective study consisted of 100 pregnant women who presented to a German Tertiary Perinatal Center between 2017 and 2020 due to a shortened cervix defined as a cervical length of 25 mm or shorter measured by transvaginal ultrasound before 34 weeks of gestation. At the time of admission, gestational age ranged from 18 + 4 to 33 + 3 weeks (+ days) of pregnancy. All patients underwent urine polymerase chain reaction (PCR) for genital Mycoplasma [Ureaplasma (U.) urealyticum, U. parvum, M. hominis or M. genitalium]. Patients who were tested positive underwent a therapy with macrolides (azithromycin or clarithromycin).

RESULTS

37% of the patients were positive for Ureaplasma spp., whereas 5% (5 patients) were Mycoplasma spp.-positive. All the latter were simultaneously colonised with Ureaplasma spp. Ureaplasma-positive patients were significantly younger than those who were tested negative. Median maternal age at examination was 30 years (a) versus 31a (p = 0.04). There was no difference between Ureaplasma-positive and -negative patients regarding median maternal body mass index (BMI) (kg/m2) (23.4 versus 22.3, p = 0.41), cervical length at admission (mm) (15 versus 17, p = 0.17), gestational age at examination (days, d) (198 versus 197, p = 0.97) or gestational age at birth (d) (250 versus 257, p = 0.33), respectively. Comparing U. parvum-positive and U. urealyticum-positive patients, there was some weak indication that U. parvum-positive patients may get a shortening of the cervix earlier in pregnancy, as the median gestational age at examination was 196d versus 215d (p = 0.06). Regarding Mycoplasma-positive and -negative patients, there was no difference in all examined parameters.

CONCLUSIONS

Overall, one-third of all women in our study with a shortened cervix before 34th week of pregnancy were colonised with genital Mycoplasma spp. We were able to show that pregnant women, who were treated with antibiotics when tested positive for genital Mycoplasma, gave birth at the same gestational age as patients with a shortened cervix without detected Mycoplasma. This raises the question of whether routine testing and early antibiotic treatment should be established in prenatal care.

Increase in the solubility of uvsY using a site saturation mutagenesis library for application in a lyophilized reagent for recombinase polymerase amplification

BACKGROUND

Recombinase uvsY from bacteriophage T4, along with uvsX, is a key enzyme for recombinase polymerase amplification (RPA), which is used to amplify a target DNA sequence at a constant temperature. uvsY, though essential, poses solubility challenges, complicating the lyophilization of RPA reagents. This study aimed to enhance uvsY solubility.

METHODS

Our hypothesis centered on the C-terminal region of uvsY influencing solubility. To test this, we generated a site-saturation mutagenesis library for amino acid residues Lys91-Glu134 of the N-terminal (His)6-tagged uvsY.

RESULTS

Screening 480 clones identified A116H as the variant with superior solubility. Lyophilized RPA reagents featuring the uvsY variant A116H demonstrated enhanced performance compared to those with wild-type uvsY.

CONCLUSIONS

The uvsY variant A116H emerges as an appealing choice for RPA applications, offering improved solubility and heightened lyophilization feasibility.

Effects of Ureaplasma parvum infection in the exosome biogenesis-related proteins in ectocervical epithelial cells

Ureaplasma parvum is a mycoplasma commonly associated with female reproductive pathologies, such as preterm birth and infertility. It can survive intracellularly and utilize exosomes to propagate infection and its virulence factors. This study explored the differential protein composition of exosomes derived from normal and U. parvum-infected cells. We also investigated the impact of U. parvum on exosome biogenesis in ectocervical epithelial cells. Ectocervical epithelial (ECTO) cells were infected with U. parvum, and immunocytochemical staining was performed using U. parvum-specific marker multiple banded antigen (mba) and exosome marker CD9. NanoLC-MS/MS analysis was conducted to identify differentially expressed proteins in exosomes. Ingenuity Pathway Analysis (IPA) was performed to identify affected canonical pathways and biological functions associated with the protein cargo of exosomes. Western blot analysis of ECTO cells validated the proteomic findings in ECTO cells. U. parvum exhibited colonization of ECTO cells and colocalization with CD9-positive intraluminal vesicles. Proteomic analysis revealed decreased protein abundance and distinct protein profiles in exosomes derived from U. parvum-infected ECTO cells. Differentially expressed proteins were associated with clathrin-mediated endocytosis and various signaling pathways indicative of infection, inflammation, and cell death processes. Additionally, U. parvum infection altered proteins involved in exosome biogenesis. In ECTO cells, U. parvum infection significantly decreased clathrin, ALIX, CD9, and CD63 and significantly increased TSG101, Rab5, Rab35, and UGCG. These findings contribute to our understanding of the infection mechanism and shed light on the importance of exosome-mediated communication in the pathophysiology of diseases affecting the cervix, such as cervicitis and preterm birth.

Next-generation sequencing-based detection of Ureaplasma in the gastric fluid of neonates with respiratory distress and chorioamnionitis

BACKGROUND

Respiratory distress is common in neonates admitted to neonatal intensive care units. Additionally, infectious diseases such as intrauterine infections or vertical transmission are important underlying causes of respiratory failure. However, pathogens often cannot be identified in neonates, and there are many cases in which antibacterial drugs are empirically administered. Next-generation sequencing (NGS) is advantageous in that it can detect trace amounts of bacteria that cannot be detected by culturing or bacteria that are difficult to cultivate. However, there are few reports on the diagnosis of infectious diseases using NGS in the neonatal field, especially those targeting respiratory distress.

OBJECTIVE

The purpose of our study was to investigate the microorganisms associated with neonatal respiratory distress and to determine whether less invasive collection specimens such as plasma and gastric fluid are useful.

METHODS

Neonates were prospectively recruited between January and August 2020 from Nagoya University Hospital. The inclusion criteria were as follows: 1) admission to the neonatal intensive care unit; 2) respiratory distress presentation within 48 h of birth; and 3) suspected infection, collection of blood culture, and administration of antibiotics. Plasma samples and blood cultures were simultaneously collected. Gastric fluid samples were also collected if the patient was not started on enteral nutrition. Information on the patients and their mothers were collected from the medical records. DNA was extracted from 140 µL of plasma and gastric fluid samples. DNA sequencing libraries were prepared, and their quality was analyzed. DNA libraries were sequenced using high-throughput NGS. The NGS data of plasma and gastric fluid samples were analyzed using the metagenomic pipeline PATHDET, which calculated the number of reads assigned to microorganisms and their relative abundance. Putative pathogens were listed.

RESULTS

Overall, 30 plasma samples and 25 gastric fluid samples from 30 neonates were analyzed. Microorganism-derived reads of gastric fluid samples were significantly higher than those of plasma samples. Transient tachypnea of the newborn was the most common cause of respiratory distress with 13 cases (43%), followed by respiratory distress syndrome with 7 cases (23%). There were 8 cases (29%) of chorioamnionitis and 7 cases (25%) of funisitis pathologically diagnosed. All blood cultures were negative, and only two gastric fluid cultures were positive for group B Streptococcus (Patient 15) and Candida albicans (Patient 24). Putative pathogens that met the positive criteria for PATHET were detected in four gastric fluid samples, one of which was group B Streptococcus from Patient 15. In the gastric fluid sample of Patient 24, Candida albicans were detected by NGS but did not meet the positive criteria for PATHDET. Cluster analysis of the plasma samples divided them into two study groups, and the indicator genera of each cluster (Phormidium or Toxoplasma) are shown in Figure 1. Clinical findings did not show any significant differences between the two groups. Cluster analysis of the gastric fluid samples divided them into three study groups, and the indicator genera of each cluster (Ureaplasma, Nostoc, and Streptococcus) are shown in Figure 2. The incidence rate of chorioamnionitis was significantly higher in Ureaplasma group than in the other two groups.

CONCLUSION

Gastric fluid may be useful for assessing neonatal patients with respiratory distress. To the best of our knowledge, this was the first study to reveal that the presence of Ureaplasma in the gastric fluid of neonates with respiratory distress was associated with chorioamnionitis. The early diagnosis of intra-amniotic infections using gastric fluid and its treatment may change the treatment strategy for neonatal respiratory distress. Screening for Ureaplasma in neonates with respiratory distress may reduce the need for empirical antibiotic administration. Further research is required to confirm these findings.

Antibiotic administration reduced intra-amniotic inflammation 7 days after preterm premature rupture of the membranes with intra-amniotic infection

OBJECTIVE

Intra-amniotic infections increase the risk of preterm delivery and short- and long-term fetal morbidity; however, no consensus exists on the choice of antimicrobial agents as treatment for these infections. We aimed to examine the efficacy of intravenous administration of sulbactam/ampicillin (SBT/ABPC) and azithromycin (AZM) for intra-amniotic infection in patients with preterm premature rupture of membranes (PPROM).

METHODS

This study followed a single-centered retrospective cohort design. We compared changes in interleukin 6 (IL-6) levels and the load of Ureaplasma species DNA in the amniotic fluid between singleton pregnancy patients with intra-amniotic infection (Group A) and without either intra-amniotic inflammation (IAI) or microbial invasion of the amniotic cavity (MIAC) (Group B) who developed PPROM between week 22, day 0 and week 33, day 6 of gestation and maintained pregnancy for ≥7 d after diagnosis (August 2014 to April 2020). Patients in Group A were treated with SBT/ABPC and AZM, whereas those in Group B were treated with ABPC and AZM or clarithromycin.

RESULTS

Thirty-one patients with IAI and 48 patients without either IAI or MIAC at diagnosis of PPROM underwent pregnancy/delivery management at our hospital. Following the study population selection, we evaluated six patients in Group A and 13 patients in Group B. Amniotic fluid IL-6 concentrations at the initial amniocentesis were high, ranging from 11.7 ng/mL to 139.2 ng/mL, indicating a state of severe IAI in all six patients in Group A. In five of the six patients in Group A, the amniotic fluid cultures during the first amniocentesis included Ureaplasma species only. In both groups, the amniotic fluid IL-6 concentration at the follow-up amniocentesis was lower than that at the initial amniocentesis (Group A: follow-up median 3.06 ng/mL [quartiles, 1.75-6.74], initial median 30.53 ng/mL [quartiles, 15.60-67.07], p＝.03; Group B: follow-up median 0.40 ng/mL [quartiles, 0.18-0.69], initial median 0.96 ng/mL [quartiles, 0.65-1.42], p＝.005); Group A showed a greater decrease than Group B (p < .001). No difference was found between the microbial loads of Ureaplasma species DNA in the initial and follow-up amniocentesis (p = .13).

CONCLUSIONS

In patients with PPROM and intra-amniotic infection, IL-6 levels in the amniotic fluid decreased significantly from before antimicrobial administration to day 7. This decrease is thought to be mainly due to the effects of intravenous AZM. The efficacy of AZM in patients with PPROM needs to be further confirmed via randomized controlled studies in the future.

Modeling an ascending infection by Ureaplasma parvum and its cell signaling and inflammatory response at the feto-maternal interface

PROBLEM

Ascending bacterial infection is associated with ∼ 40% of spontaneous preterm birth (PTB), and Ureaplasma spp. is one of the most common bacteria isolated from the amniotic fluid. Developing novel in vitro models that mimic in vivo uterine physiology is essential to study microbial pathogenesis. We utilized the feto-maternal interface organ-on-chip (FMi-OOC) device and determined the propagation of Ureaplasma parvum, and its impact on cell signaling and inflammation.

METHOD OF STUDY

FMi-OOC is a microphysiologic device mimicking fetal membrane/decidua interconnected through microchannels. The impact of resident decidual CD45+ leukocytes was also determined by incorporating them into the decidual chamber in different combinations with U. parvum. We tested the propagation of live U. parvum from the decidual to the amniochorion membranes (immunocytochemistry and quantitative PCR), determined its impact on cytotoxicity (LDH assay), cell signaling (JESSTM Western Blot), cellular transition (immunostaining for vimentin and cytokeratin), and inflammation (cytokine bead array).

RESULTS

U. parvum transversed the chorion and reached the amnion epithelium after 72 hours but did not induce cell signaling kinases (p38MAPK and JNK) activation, or cellular transition (epithelial-mesenchymal), regardless of the presence of immune cells. The inflammatory response was limited to the choriodecidual interface and did not promote inflammation in the amnion layer.

CONCLUSIONS

Our data suggest that U. parvum is poorly immunogenic and does not produce massive inflammatory changes at the feto-maternal interface. We speculate that the presence of U. parvum may still compromise the feto-maternal interface making it susceptible to other pathogenic infection.

Placental histopathology, maternal characteristics and neonatal outcome in cases of preterm birth in a high-risk population in South Africa

Background. Preterm birth remains a global health concern and is one of the most common pregnancy complications associated with perinatal morbidity and mortality.Objective. To investigate placental pathology and its associations with obstetric, maternal and neonatal outcomes in the Eastern Cape region of South Africa (SA) in order to help understand its associations with preterm birth in that region. Methods. In this prospective study, placentas were collected consecutively from patients attending a public tertiary referral hospital in SA, delivering preterm (n=100; 28 - 34 weeks gestational age) and term (n=20; >36 weeks gestational age). Placentas were submitted for histopathology, and comparisons with maternal characteristics and neonatal outcomes in preterm birth were undertaken.Results. Histological analysis revealed pathology in all preterm placentas (100%), with maternal vascular malperfusion (47%) and abruptio placentae (41%) most commonly identified. Acute chorioamnionitis (21%) was associated with term births (p=0.002). Maternal characteristics and neonatal outcomes significantly associated with preterm birth included pre-eclampsia (p=0.006), neonatal respiratory distress syndrome (p=0.004) and neonatal jaundice (p=0.003). Intrauterine demise (p=0.004) and alcohol abuse (p≤0.005) were significantly associated with term delivery. The number of mothers delivering preterm who were HIV-positive was high (41%). Conclusion. The pathology identified in all preterm placentas supports the need to update institutional policies for submission of placentas from all preterm births for histopathology, particularly in countries with a high burden of preterm birth.

Relationship of maternal inflammatory response and fetal inflammatory response to duration and intensity of intra-amniotic infection and inflammation

INTRODUCTION

We aimed to use two indices, amniotic fluid interleukin-6 (IL-6) concentration at diagnosis and diagnosis-to-delivery interval, to clarify the frequencies of maternal inflammatory response (MIR) and fetal inflammatory response (FIR) in the placenta of patients with intra-amniotic infection and intra-amniotic inflammation (IAI).

METHODS

This is a single-center retrospective cohort study. From August 2014 to April 2020, participants were diagnosed with IAI with or without microbial invasion of the amniotic cavity (MIAC) using amniocentesis. IAI was defined as concentrations of amniotic IL-6 ≥ 2.6 ng/mL. MIAC was defined as a positive amniotic fluid culture. IAI with MIAC was defined as an intra-amniotic infection. We calculated the cut-off values for IL-6 concentration in the amniotic fluid at diagnosis and the diagnosis-to-delivery interval for MIR-positive cases among those with intra-amniotic infection.

RESULTS

The amniotic fluid IL-6 concentration at diagnosis and diagnosis-to-delivery interval were 15.8 ng/mL and 12 h, respectively. Among cases with intra-amniotic infection, MIR was 98% (52/53) positive, i.e., when either of the two cut-off values was exceeded. There were no significant differences between the frequencies of MIR and FIR. In cases with IAI but no MIAC, the frequencies of MIR and FIR were significantly lower than those with intra-amniotic infection, except when neither of the two cut-off values was exceeded.

DISCUSSION

We clarified the MIR- and FIR-positive cases in intra-amniotic infection and cases with IAI but no MIAC according to condition, including the diagnosis-to-delivery interval.

Diagnostic accuracy of amniotic fluid interleukin-6 for fetal inflammatory response syndrome

AIM

This study aimed to clarify the diagnostic accuracy of amniotic fluid interleukin-6 for fetal inflammatory response syndrome (FIRS).

METHODS

This retrospective cohort study was conducted in a single institution and targeted cases of preterm birth within 24 h after amniocentesis among singleton cases that underwent amniocentesis at our hospital for suspected intraamniotic inflammation (IAI) from gestational ages of 22-36 weeks between August 2014 and March 2020. FIRS was defined as >11.0 pg/mL of umbilical cord blood interleukin-6.

RESULTS

The analysis included 158 pregnant women. There was a strong correlation between amniotic fluid interleukin-6 and umbilical cord blood interleukin-6 (r = 0.70, p < 0.001). The area under the receiver operating characteristic curve of amniotic fluid interleukin-6 for FIRS was 0.93, with a cutoff value of 15.5 ng/mL, and showed high sensitivity and specificity (0.91 and 0.88, respectively). An amniotic fluid interleukin-6 cutoff value of ≥15.5 ng/mL was associated with a significant risk of FIRS (adjusted odds ratio: 27.9; 95% confidence interval: 6.3-123.0; p < 0.001).

CONCLUSIONS

The results of this study show that amniotic interleukin 6 alone can be used to diagnose FIRS prenatally. While there is a need for validation, it may be possible to treat IAI while preventing damage to the central nervous and respiratory systems in the uterus by keeping the amniotic fluid interleukin-6 below the cutoff value.

Recombinase polymerase amplification using novel thermostable strand-displacing DNA polymerases from Aeribacillus pallidus and Geobacillus zalihae

Recombinase polymerase amplification (RPA) is an isothermal DNA amplification reaction at around 41 °C using recombinase (Rec), single-stranded DNA-binding protein (SSB), and strand-displacing DNA polymerase (Pol). Component instability and the need to store commercial kits in a deep freezer until use are some limitations of RPA. In a previous study, Bacillus stearothermophilus Pol (Bst-Pol) was used as a thermostable strand-displacing DNA polymerase in RPA. Here, we attempted to optimize the lyophilization conditions for RPA with newly isolated thermostable DNA polymerases for storage at room temperature. We isolated novel two thermostable strand-displacing DNA polymerases, one from a thermophilic bacterium Aeribacillus pallidus (H1) and the other from Geobacillus zalihae (C1), and evaluated their performances in RPA reaction. Urease subunit β (UreB) DNA from Ureaplasma parvum serovar 3 was used as a model target for evaluation. The RPA reaction with H1-Pol or C1-Pol was performed at 41 °C with the in vitro synthesized standard UreB DNA. The minimal initial copy numbers of standard DNA from which the amplified products were observed were 600, 600, and 6000 copies for RPA with H1-Pol, C1-Pol, and Bst-Pol, respectively. Optimization was carried out using RPA components, showing that the lyophilized RPA reagents containing H1-Pol exhibited the same performance as the corresponding liquid RPA reagents. In addition, lyophilized RPA reagents with H1-Pol showed almost the same activity after two weeks of storage at room temperature as the freshly prepared liquid RPA reagents. These results suggest that lyophilized RPA reagents with H1-Pol are preferable to liquid RPA reagents for onsite use.

Ureaplasma parvum infection induces inflammatory changes in vaginal epithelial cells independent of sialidase

BACKGROUND

Ureaplasma, a genus of the order Mycoplasmatales and commonly grouped with Mycoplasma as genital mycoplasma is one of the most common microbes isolated from women with infection/inflammation-associated preterm labor (PTL). Mycoplasma spp. produce sialidase that cleaves sialic acid from glycans of vaginal mucous membranes and facilitates adherence and invasion of the epithelium by pathobionts, and dysregulated immune response. However, whether Ureaplasma species can induce the production of sialidase is yet to be demonstrated. We examined U. parvum-infected vaginal epithelial cells (VECs) for the production of sialidase and pro-inflammatory cytokines.

METHODS

Immortalized VECs were cultured in appropriate media and treated with U. parvum in a concentration of 1 × 10⁵ DNA copies/ml. After 24 h of treatment, cells and media were harvested. To confirm infection and cell uptake, immunocytochemistry for multi-banded antigen (MBA) was performed. Pro-inflammatory cytokine production and protein analysis for sialidase confirmed pro-labor pathways.

RESULTS

Infection of VECs was confirmed by the presence of intracellular MBA. Western blot analysis showed no significant increase in sialidase expression from U. parvum-treated VECs compared to uninfected cells. However, U. parvum infection induced 2-3-fold increased production of GM-CSF (p = 0.03), IL-6 (p = 0.01), and IL-8 (p = 0.01) in VECs compared to controls.

CONCLUSION

U. parvum infection of VECs induced inflammatory imbalance associated with vaginal dysbiosis but did not alter sialidase expression at the cellular level. These data suggest that U. parvum's pathogenic effect could be propagated by locally produced pro-inflammatory cytokines and, unlike other genital mycoplasmas, may be independent of sialidase.

Maternal Baseline Risk Factors for Abnormal Vaginal Colonisation among High-Risk Pregnant Women and the Association with Adverse Pregnancy Outcomes: A Retrospective Cohort Study

Abnormal vaginal colonisation can lead to adverse pregnancy outcomes such as preterm birth through intra-amniotic inflammation. Despite the concern, little is known about its risk factors and impact in pregnant women at high-risk for spontaneous preterm birth. Thus, we conducted this single-centre retrospective cohort study including 1381 consecutive women who were admitted to the high-risk pregnancy unit. The results of vaginal culture at admission were categorised according to the colonising organism: bacteria (Gram-negative or -positive) and genital mycoplasmas. Maternal baseline socioeconomic, and clinical characteristics, as well as pregnancy, delivery, and neonatal outcomes were compared according to the category. Maternal risk factors for Gram-negative colonisation included advanced maternal age, increased pre-pregnancy BMI, a greater number of past spontaneous abortions, earlier gestational age at admission, and IVF. Gram-positive colonisation was likewise associated with earlier gestational age at admission. Genital mycoplasmal colonisation was associated with a greater number of past induced abortions, a lower level of education completed, and a lower rate of multifetal pregnancy and IVF. The neonates from mothers with Gram-negative colonisation had a greater risk of NICU admission, proven early onset neonatal sepsis, and mortality. However, not Gram-positive bacteria or genital mycoplasma was directly associated with adverse pregnancy outcomes.

Intrauterine Ureaplasma is associated with small airway obstruction in extremely preterm infants

BACKGROUND

The long-term follow-up of lung function (LF) in extremely preterm (EP) infants with bronchopulmonary dysplasia (BPD) has shown a worldwide increase in small airway obstructions (SAO).

OBJECTIVES

We investigated the relationships between intrauterine Ureplasma infection in EP infants and bubbly/cystic lung, BPD, and SAO at school age.

METHODS

Placental pathology, placental Ureaplasma DNA (pU-DNA), and cord blood immunoglobulin M (IgM) (C-IgM) were investigated in 360 EP infants born from 1981 to 2004. Maternal amniotic inflammatory response (M-AIR) scores and hemosiderin deposition (HD) were estimated in the chorioamnion. The study subjects were divided into groups based on their M-AIR scores. Their LF at school age was compared with those of 33 healthy siblings.

FINDINGS

pU-DNA and C-IgM were significantly related to SAO at school age (p < 0.012). M-AIR score 3 and pU-DNA >1000 units had an odds ratio (OR) of 35 (95% confidence interval: 10-172) and 18 (5.6-67) for bubbly/cystic lung, and 11 (3.1 - 43) and 31 (4.5-349) for severe BPD, and 5.3 (2.1-11) and 12 (2.4-74) for SAO, respectively. The ORs of surfactant treatment, BPD grade III, O₂ at 40 weeks, HD, and C-IgM >30 mg/dl for SAO were 0.21 (0.075-0.58), 5.3 (2.1-15), 2.5 (1.4-4.6), 3.6 (1.5-9.1) and 2.5 (1.0-5.2). 84% (90/107) SAO infants showed no or mild BPD in infancy, and 61% of infants had no severe CAM.

CONCLUSION

Our long-term cohort study of LF in EP infants revealed that intrauterine Ureaplasma was associated with bubbly/cystic lung, severe BPD, and SAO at school age.

Modeling ascending Ureaplasma parvum infection through the female reproductive tract using vagina-cervix-decidua-organ-on-a-chip and feto-maternal interface-organ-on-a-chip

Genital mycoplasmas can break the cervical barrier and cause intraamniotic infection and preterm birth. This study developed a six-chamber vagina-cervix-decidua-organ-on-a-chip (VCD-OOC) that recapitulates the female reproductive tract during pregnancy with culture chambers populated by vaginal epithelial cells, cervical epithelial and stromal cells, and decidual cells. Cells cultured in VCD-OOC were characterized by morphology and immunostaining for cell-specific markers. We transferred the media from the decidual cell chamber of the VCD-OOC to decidual cell chamber in feto-maternal interface organ-on-a-chip (FMi-OOC), which contains the fetal membrane layers. An ascending Ureaplasma parvum infection was created in VCD-OOC. U. parvum was monitored for 48 h post-infection with their cytotoxicity (LDH assay) and inflammatory effects (multiplex cytokine assay) in the cells tested. An ascending U. parvum infection model of PTB was developed using CD-1 mice. The cell morphology and expression of cell-specific markers in the VCD-OOC mimicked those seen in lower genital tract tissues. U. parvum reached the cervical epithelial cells and decidua within 48 h and did not cause cell death in VCD-OOC or FMi-OOC cells. U. parvum infection promoted minimal inflammation, while the combination of U. parvum and LPS promoted massive inflammation in the VCD-OOC and FMi-OOC cells. In the animal model, U. parvum vaginal inoculation of low-dose U. parvum did not result in PTB, and even a high dose had only some effects on PTB (20%). However, intra-amniotic injection of U. parvum resulted in 67% PTB. We report the colonization of U. parvum in various cell types; however, inconsistent, and low-grade inflammation across multiple cell types suggests poor immunogenicity induced by U. parvum.

Exosomes from Ureaplasma parvum-infected ectocervical epithelial cells promote feto-maternal interface inflammation but are insufficient to cause preterm delivery

This study determined if exosomes from ectocervical epithelial (ECTO) cells infected with Ureaplasma parvum (U. parvum) can carry bacterial antigens and cause inflammation at the feto-maternal interface using two organ-on-chip devices, one representing the vagina-cervix-decidua and another one mimicking the feto-maternal interface, and whether such inflammation can lead to preterm birth (PTB). Exosomes from U. parvum-infected ECTO cells were characterized using cryo-electron microscopy, nanoparticle tracking analysis, Western blot, and Exoview analysis. The antigenicity of the exosomes from U. parvum-infected ECTO cells was also tested using THP-1 cells and our newly developed vagina-cervix-decidua organ-on-a-chip (VCD-OOC) having six microchannel-interconnected cell culture chambers containing cells from the vagina, ectocervical, endocervical, transformation zone epithelia, cervical stroma, and decidua. The VCD-OOC was linked to the maternal side of our previously developed feto-maternal interface organ-on-a-chip (FMi-OOC). Cell culture media were collected after 48 h to determine the cytokine levels from each cell line via ELISA. For physiological validation of our in vitro data, high-dose exosomes from U. parvum-infected ECTO cells were delivered to the vagina of pregnant CD-1 mice on E15. Mice were monitored for preterm birth (PTB, < E18.5 days). Exosomes from ECTO cells infected with U. parvum (UP ECTO) showed significant downregulation of exosome markers CD9, CD63, and CD81, but contained multiple banded antigen (MBA), a U. parvum virulence factor. Monoculture experiments showed that exosomes from UP ECTO cells delivered MBA from the host cell to uninfected endocervical epithelial cells (ENDO). Moreover, exposure of THP-1 cells to exosomes from UP ECTO cells resulted in increased IL-8 and TNFα and reduced IL-10. The OOC experiments showed that low and high doses of exosomes from UP ECTO cells produced a cell type-specific inflammatory response in the VCD-OOC and FMi-OOC. Specifically, exosomes from UP ECTO cells increased pro-inflammatory cytokines such as GM-CSF, IL-6, and IL-8 in cervical, decidual, chorion trophoblast, and amnion mesenchymal cells. The results from our OOC models were validated in our in vivo mice model. The inflammatory response was insufficient to promote PTB. These results showed the potential use of the VCD-OOC and FMi-OOC in simulating the pathophysiological processes in vivo.

Estimated time to emergence of secondary intra-amniotic infection or inflammation since the onset of the preterm premature rupture of membranes

OBJECTIVE

Prematurity is the most important prognostic factor for infants born following preterm premature rupture of membranes (PPROM). Therefore, when PPROM occurs between 22 and 33 weeks of gestation, prolonging pregnancy is recommended. Determination of management strategies requires screening for the presence of intra-amniotic infection or inflammation at the time of PPROM diagnosis. If intra-amniotic infection/inflammation is not detected, it is important to monitor the patient to diagnose any new infection/inflammation. We examined the period from PPROM to secondary intra-amniotic infection/inflammation and associated factors.

MATERIALS AND METHODS

This retrospective study was conducted at a single facility. We examined 26 patients who experienced PPROM between 26 and 33 weeks of gestation and were negative for intra-amniotic infection/inflammation at the time of diagnosis and underwent serial amniocentesis. Antibiotic therapy comprising ampicillin, amoxicillin, and clarithromycin for 7 days was started after the first amniocentesis. The period from PPROM to secondary intra-amniotic infection/inflammation was analyzed using a Kaplan-Meier survival curve. The onset of intra-amniotic infection/inflammation was considered as the time at which amniotic fluid bacterial culture results became positive, the time when amniotic fluid Interleukin (IL)-6 increased beyond 2.6 ng/mL, or the day of delivery if histological chorioamnionitis was observed in the delivered placenta. Patients were treated as censored if no intra-amniotic infection/inflammation could be confirmed in the amniotic fluid and delivered placenta.

RESULTS

The median time from PPROM to secondary intra-amniotic infection/inflammation was 18 days. Six patients developed intra-amniotic infection/inflammation, while 13 patients without intra-amniotic infections/inflammation delivered fewer than 7 days after PPROM. No confounding factors at the time of PPROM diagnosis were associated with the time from PPROM until secondary intra-amniotic infection/inflammation.

CONCLUSIONS

The time between PPROM and onset of secondary intra-amniotic infection/inflammation appears prolonged. Treatments other than antimicrobial agents may need to be added to prolong pregnancy.

Genital infection with Ureaplasma urealyticum and its effect on pregnancy

Chorioamnionitis or intra-amniotic infection is an infection that affects the intrauterine content during pregnancy. Numerous studies have reported vaginal colonization with various types of infectious agents as a risk factor for chorioamnionitis. Although this complication occurs due to the ascending polymicrobial bacterial infection at the time of membrane breakage, it may also occur in pregnant women with intact membranes, mainly due to Ureaplasma urealyticum (U. urealyticum) and Mycoplasma hominis (M. hominis). The main aim of the present study was to identify a region-specific panel of infectious agents that can be used more accurately determine premature birth, as well as the premature rupture of membranes (PROM). Thus, a 10-year retrospective study was conducted. A total of 1,301 pregnant women with PROM and premature birth or spontaneous abortion were included in the study. It was observed that the main infectious agent varied in the five groups analyzed in total. The infectious agent distribution also varied depending on environmental parameters. Ureaplasma was found to be the most frequently detected germ amongst the infectious agents of the vaginal cultures from pregnant women enrolled in the present study, regardless of gestational age. On the whole, the findings of the present study suggest that additional studies are required, in order to confirm that diagnosis and treatment according to laboratory results of vaginal infections with U. urealyticum/M. hominis during the first trimester of pregnancy could prevent premature birth, abortion or chorioamnionitis.

SARS-CoV-2, Zika viruses and mycoplasma: Structure, pathogenesis and some treatment options in these emerging viral and bacterial infectious diseases

The molecular evolution of life on earth along with changing environmental, conditions has rendered mankind susceptible to endemic and pandemic emerging infectious diseases. The effects of certain systemic viral and bacterial infections on morbidity and mortality are considered as examples of recent emerging infections. Here we will focus on three examples of infections that are important in pregnancy and early childhood: SARS-CoV-2 virus, Zika virus, and Mycoplasma species. The basic structural characteristics of these infectious agents will be examined, along with their general pathogenic mechanisms. Coronavirus infections, such as caused by the SARS-CoV-2 virus, likely evolved from zoonotic bat viruses to infect humans and cause a pandemic that has been the biggest challenge for humanity since the Spanish Flu pandemic of the early 20th century. In contrast, Zika Virus infections represent an expanding infectious threat in the context of global climate change. The relationship of these infections to pregnancy, the vertical transmission and neurological sequels make these viruses highly relevant to the topics of this special issue. Finally, mycoplasmal infections have been present before mankind evolved, but they were rarely identified as human pathogens until recently, and they are now recognized as important coinfections that are able to modify the course and prognosis of various infectious diseases and other chronic illnesses. The infectious processes caused by these intracellular microorganisms are examined as well as some general aspects of their pathogeneses, clinical presentations, and diagnoses. We will finally consider examples of treatments that have been used to reduce morbidity and mortality of these infections and discuss briefly the current status of vaccines, in particular, against the SARS-CoV-2 virus. It is important to understand some of the basic features of these emerging infectious diseases and the pathogens involved in order to better appreciate the contributions of this special issue on how infectious diseases can affect human pregnancy, fetuses and neonates.

Blockade of endoplasmic reticulum stress-induced cell death by Ureaplasma parvum vacuolating factor

Previously, we found that Ureaplasma parvum internalised into HeLa cells and cytosolic accumulation of galectin-3. U. parvum induced the host cellular membrane damage and survived there. Here, we conducted vesicular trafficking inhibitory screening in yeast to identify U. parvum vacuolating factor (UpVF). U. parvum triggered endoplasmic reticulum (ER) stress and upregulated the unfolded protein response-related factors, including BiP, P-eIF2 and IRE1 in the host cells, but it blocked the induction of the downstream apoptotic factors. MicroRNA library screening of U. parvum-infected cells and UpVF-transfected cells identified miR-211 and miR-214 as the negative regulators of the apoptotic cascade under ER stress. Transient expression of UpVF induced HeLa cell death with intracellular vacuolization; however, some stable UpVF transformant survived. U. parvum-infected cervical cell lines showed resistance to actinomycin D, and UpVF stable transformant cell lines exhibited resistance to X-ray irradiation, as well as cisplatin and paclitaxel. UpVF expressing cervical cancer xenografts in nude mice also acquired resistance to cisplatin and paclitaxel. A mycoplasma expression vector based on Mycoplasma mycoides, Syn-MBA (multiple banded antigen)-UpVF, reduced HeLa cell survival compared with that of Syn-MBA after 72 hr of infection. These findings together suggest novel mechanisms for Ureaplasma infection and the possible implications for cervical cancer malignancy. TAKE AWAYS: • Ureaplasmal novel virulence factor, UpVF, was identified. • UpVF triggered ER stress but suppressed apoptotic cascade via miR-211 and -214. • UpVF conferred resistance to anticancer treatments both in vivo and in vitro. • Dual expression of MBA and UpVF in JCVI-syn3B showed host cell damage.

Placental histopathology in preterm birth with confirmed maternal infection: A systematic literature review

Four in five neonatal deaths of preterm births occur in low and middle income countries and placental histopathology examination can help clarify the pathogenesis. Infection is known to play a significant role in preterm birth. The aim of this systematic review is to explore the association between placental histopathological abnormality and preterm birth in the presence of confirmed infection. PubMed/Medline, Scopus, Web of Science and Embase were searched using the keywords related to preterm birth, placental histopathology and infection. Titles and abstracts were screened and the full texts of eligible articles were reviewed to extract and summarise data. Of 1529 articles, only 23 studies (13 bacterial, 6 viral and 4 parasitic) were included, and they used 7 different gestational age windows, and 20 different histopathological classification systems, precluding data pooling. Despite this, histopathological chorioamnionitis, and funisitis (when examined) were commonly observed in preterm birth complicated by confirmed bacterial or viral, but not parasitic, infection. The presence of malaria parasites but not pigment in placenta was reported to increase the risk of PTB, but this finding was inconclusive. One in three studies were conducted in low and middle income countries. An array of: definitions of preterm birth subgroups, histological classification systems, histopathologic abnormalities and diagnostic methods to identify infections were reported in this systematic review. Commitment to using standardised terminology and classification of histopathological abnormalities associated with infections is needed to identify causality and potential treatment of preterm birth. Studies on preterm birth needs to occur in high burden countries and control for clinical characteristics (maternal, fetal, labor, and placental) that may have an impact on placental histopathological abnormalities.

Effect of probiotics on vaginal Ureaplasma parvum in women suffering from unexplained infertility

RESEARCH QUESTION

Does oral probiotic supplementation influence the relative abundance of different vaginal microbiota in women experiencing infertility?

DESIGN

A prospective, monocentric randomized controlled trial. To study the influence of probiotics on infertility, 80 patients with primary or secondary infertility were included. Patients were assigned to either a probiotic treatment or a control group. Participants in the treatment group (n = 40) took one sachet (2 g) a day of a defined probiotic supplement limiting Lactobacillus strains. Patients in the control group did not receive any additional probiotic supplements. Vaginal samples were taken on day 20 of the menstrual cycle and 4 weeks later, on day 20, of the consecutive cycle. Subsequently, 16s rRNA gene analysis of the vaginal samples was conducted.

RESULTS

After the intervention phase, no effects on alpha diversity resulting from treatment could be observed. The between sample diversity of different women (beta diversity) at baseline had no effects of age, treatment group or body mass index. Primary or secondary sterility, however, had a significant effect on community. Three clusters (Lactobacillus crispatus, Lactobacillus iners and Lactobacillus gasseri) were identified as the leading representatives. Furthermore, patients treated with probiotics showed limited growth of Ureaplasma parvum compared with the control group (P = 0.021).

CONCLUSIONS

This study points to a possible protective effect of probiotic supplements on the vaginal microbiota. It is tempting to speculate that this effect assists in containing the growth of non-beneficial bacteria and helps to prevent or cure a dysbiotic vaginal flora.

Perinatal Infections With Ureaplasma

Ureaplasma species are increasingly recognized as relevant pathogens in prenatal, perinatal and postnatal morbidity. They are commonly found as commensals on the mucous membranes of the lower urogenital tract of pregnant women, but when ascending, they can cause bacterial vaginosis, chorioamnionitis, premature birth and postnatal morbidities such as bronchopulmonary dysplasia, and early-onset neonatal sepsis and meningitis. The detection of Ureaplasma species is challenging and is not covered by routine diagnostics, and current empiric antibiotic treatment in neonates suspected of infection is not directed against Ureaplasma species. The aim of this review is to discuss the pathophysiology of Ureaplasma infections, the clinical consequences and the current difficulties in diagnosis and treatment by providing an overview of the current literature.

An experimental animal model of bronchopulmonary dysplasia: Secondary publication

Bronchopulmonary dysplasia (BPD) is a serious complication of preterm delivery and low birthweight infants. The incidence of BPD has not decreased, and there is no effective treatment for the disease. Since the survival rate of premature infants has increased, it has become difficult to obtain pathological tissue samples from BPD death cases. There is also no in vitro experimental system for complex three-dimensional structures, such as alveolarization and pulmonary angiogenesis; thus, the use of animal models is necessary to elucidate the pathology of BPD and develop new treatments. To date, BPD animal models were being developed by exposing immature animal lungs to various stimuli. In the present review, I summarize BPD animal models that use (i) highly concentrated oxygen, (ii) mechanical ventilation, and (iii) infection/inflammation. In addition, with mesenchymal stromal cell (MSC) therapy for BPD as an example, I will discuss the expectations for new treatments that would be applied from animal models to humans.

Validation of the loop-mediated isothermal amplification method for rapid and sensitive detection of Ureaplasma species in respiratory tracts of preterm infants

Introduction

A simple and rapid diagnosis of Ureaplasma spp. is required for the choice of the appropriate antibiotic. However, an ideal detection method has not been available. This study examines the efficacy of the loop-mediated isothermal amplification (LAMP) assay, which provides rapid and sensitive results, to detect Ureaplasma spp. in respiratory tract samples of preterm infants.

Methods

The study included preterm infants born before 32 weeks of gestation admitted Kagoshima City Hospital from June 2018 to March 2020. Nasopharyngeal swabs and/or tracheal aspirates were obtained in the first seven postnatal days. One hundred sixty-seven nasopharyngeal swabs and 101 tracheal aspirates were analyzed by LAMP, culture, and quantitative real-time polymerase chain reaction.

Results

All 167 infants had a median (range) gestational age of 28.7 weeks (22.3–30.9) and birthweight 1030g (322–1828). One hundred sixty-seven nasopharyngeal swabs and 101 tracheal aspirates were obtained. In the results of nasopharyngeal swabs, the sensitivity and specificity of LAMP were 73.9% (17/23) and 97.2% (140/144), whereas those of quantitative real-time polymerase chain reaction were 73.9% (17/23) and 95.8% (138/144), compared to culture. In the results of tracheal aspirates, the sensitivity and specificity of LAMP were 89.5% (17/19) and 92.7% (76/82), whereas those of quantitative real-time polymerase chain reaction were 89.5% (17/19) and 93.9% (77/82), compared to culture.

Conclusions

The LAMP assay showed similar sensitivity and specificity with quantitative real-time polymerase chain reaction in the respiratory tracts of preterm infants including extremely preterm infants during the immediate postnatal period. Therefore, the LAMP is a practical alternative for the early detection so that appropriate antibiotics can be administered for preventing BPD.

MicroRNAs miR-4535 and miR-1915-5p in amniotic fluid as predictive biomarkers for chorioamnionitis

Background:

This study was performed to investigate the clinical significance of miR-4535 and miR-1915-5p in severe chorioamnionitis.

Materials & methods:

Amniotic fluid samples from 37 patients with severe chorioamnionitis were subjected to miRNA array analysis and ddPCR™. Diagnostic values were assessed using the receiver operating characteristic curve. The patients were separated into three groups according to Blanc’s criteria.

Results:

The expression of miR-4535 and miR-1915-5p was significantly correlated with the copy number of 16S rDNA, had extremely high diagnostic accuracy for severe chorioamnionitis, and was linked to maternal and fetal inflammation.

Conclusion:

miR-4535 and miR-1915-5p serve as promising biomarkers for the diagnosis of severe chorioamnionitis.

Chorioamnionitis and fetal inflammatory response syndrome, which is linked to chorioamnionitis, are considered serious diseases in perinatal care. In this study, miR-4535 and miR-1915-5p are recognized as promising biomarkers for the diagnosis of chorioamnionitis before delivery. In particular, the increased expression of miR-4535 in amniotic fluid is expected to be regarded as a positive indicator for fetal inflammatory response syndrome, and the elevated expression of miR-4535 in serum is also considered to predictively diagnose intrauterine infection in pregnancy. Our results highlight that further studies should explore the underlying clinical significance of miR-4535 and miR-1915-5p.

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

OBJECTIVE

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

DESIGN

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

SETTING

Basic research laboratory.

INTERVENTION(S)

None.

ANIMALS

Mice.

MAIN OUTCOME MEASURE(S)

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

RESULT(S)

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

CONCLUSION(S)

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

Vaginal microbiota associated with preterm delivery

OBJECTIVES

The aim of this study was to evaluate whether vaginal microbiota is associated with threatened premature labor and preterm delivery.

METHODS

This prospective study enrolled 64 pregnant women who underwent vaginal microbiome analyses using 16S ribosomal RNA sequence method with informed consent. The 64 pregnant women consisted of 47 women with threatened premature labor and 17 women with other diseases (non-threatened premature labor) in a case-control study. In a cohort study of threatened premature labor group, 23 pregnancies ended in preterm delivery, and the remaining 24 ended in full-term deliveries. The differences in vaginal microbiota between threatened and non-threatened premature labor groups, and between preterm and full-term delivery groups were evaluated.

RESULTS

There were no differences in vaginal microbiota between threatened and non-threatened premature labor groups. There were significant differences between preterm and full-term delivery groups in Nugent score [median 3 (range 0-7) vs. 0 (0-4), p < 0.05], percentage of Lactobacillus species [88% (0-100) vs. 99.8% (55.4-100), p < 0.01], the number of bacterial species [3 (1-13) vs. 2 (1-5), p < 0.05], and positivity of Ureaplasma species (61% vs. 17%, p < 0.01). Univariate and multivariable analyses revealed that positivity of Ureaplasma species was a predictive factor of preterm delivery in women with threatened premature labor (OR, 6.5; 95% CI, 1.3-33.0; p < 0.05).

CONCLUSION

Increased positivity of Ureaplasma species in vaginal microbiota was a risk factor for preterm delivery among women with threatened premature labor. Vaginal microbiome analysis may identify high risk pregnancies for preterm delivery.

Neonatal Mycoplasma and Ureaplasma Infections

Mycoplasma species (spp.) can be commensals or opportunistic pathogens of the urogenital tract, and they can be commonly isolated from amniotic fluid, placenta, and fetal/neonatal tissue or blood in mothers delivering prematurely or their preterm infants. Although the presence of Mycoplasma spp. has been associated with adverse maternal-fetal outcomes such as preterm birth and maternal chorioamnionitis, it is less clear whether vertical transmission to the neonate results in colonization or active infection/inflammation. Moreover, the presence of Mycoplasma spp. in neonatal blood, cerebrospinal fluid, or tissue has been variably associated with increased risk of neonatal comorbidities, especially bronchopulmonary dysplasia (BPD). Although the treatment of the mother or neonate with antibiotics is effective in eradicating ureaplasma, it is not clear that the treatment is effective in reducing the incidence of major morbidities of the preterm neonate (eg, BPD). In this article, we review the animal and clinical data for ureaplasma-related complications and treatment strategies. [Pediatr Ann. 2020;49(7):e305-e312.].

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.

Current understanding and treatment of intra-amniotic infection with Ureaplasma spp

Considerable evidence has shown that intra-amniotic infection with Ureaplasma spp. increases the risk of chorioamnionitis and preterm labor. Ureaplasma spp. are among the smallest organisms, and their isolation is uncommon in routine clinical practice because of their size and high auxotrophy. Although Ureaplasma spp. have been reported as causative agents of preterm birth, they also have a high incidence in vaginal swabs collected from healthy reproductive-age women; this has led to questions on the virulence of Ureaplasma spp. and to them being considered as harmless commensal bacteria. Therefore, many efforts have been made to clarify the pathogenicity of Ureaplasma spp. at the molecular level. Ureaplasma spp. are surrounded by lipoproteins, including multiple-banded antigen. Both multiple-banded antigen and its derivative, that is, the synthetic lipopeptide, UPM-1, induce an inflammatory response in a preterm mice model, which was adequate to cause preterm birth or stillbirth. In this review, we present an overview of the virulence mechanisms of Ureaplasma spp. and treatment of ureaplasma infection during pregnancy to prevent possible serious sequelae in infants. In addition, relevant mechanisms underlying antibiotic resistance in Ureaplasma spp. are discussed. Ureaplasma spp. are naturally resistant against β-lactam antibiotics because of the lack of a cell wall. Azithromycin is one of the effective agents that can control intrauterine ureaplasma infection. In fact, macrolide- and fluoroquinolone-resistant isolates of Ureaplasma spp. have already been observed in perinatal practice in Japan.

Expression, Regulation, and Function of the Calmodulin Accessory Protein PCP4/PEP-19 in Myometrium

OBJECTIVE

Calmodulin (CaM) plays a key role in the orchestration of Ca²⁺ signaling events, and its regulation is considered an important component of cellular homeostasis. The control of uterine smooth muscle function is largely dependent on the regulation of Ca²⁺ and CaM signaling. The objective of this study was to investigate the expression, function, and regulation of CaM regulatory proteins in myometrium during pregnancy.

STUDY DESIGN

Myometrium was obtained from nonpregnant women and 4 groups of pregnant women at the time their primary cesarean delivery: (i) preterm not in labor, (ii) preterm in labor with clinical and/or histological diagnosis of chorioamnionitis, (3) term not in labor; and (4) term in labor. The effect of perinatal inflammation on pcp4/pep-19 expression was evaluated in a mouse model of Ureaplasma parvum-induced chorioamnionitis. Human myometrial cells stably expressing wild-type and mutant forms of PCP4/PEP-19 were used in the evaluation of agonist-induced intracellular Ca²⁺ mobilization.

RESULTS

Compared to other CaM regulatory proteins, PCP4/PEP-19 transcripts were more abundant in human myometrium. The expression of PCP4/PEP-19 was lowest in myometrium of women with preterm pregnancy and chorioamnionitis. In the mouse uterus, pcp4/pep-19 expression was lower in late compared to mid-gestation and decreased in mice injected intra-amniotic with Ureaplasma parvum. In myometrial smooth muscle cells, tumor necrosis factor alpha and progesterone decreased and PCP4/PEP-19 promoter activity increased. Finally, the overexpression of PCP4/PEP-19 reduced agonist-induced intracellular Ca²⁺ levels in myometrial cells.

CONCLUSION

The decreased expression of PCP4/PEP-19 in myometrium contributes to a loss of quiescence in response to infection-induced inflammation at preterm pregnancy.

New antibiotic regimen for preterm premature rupture of membrane reduces the incidence of bronchopulmonary dysplasia

AIM

The optimal antibiotic regimen for preterm premature rupture of membrane (pPROM) is still unclear. This study aimed to determine the effects of ampicillin-sulbactam (SBT/ABPC) and azithromycin (AZM) on the incidence of bronchopulmonary dysplasia (BPD).

METHODS

This retrospective study included women with singleton gestations and a diagnosis of pPROM between 22 and 27 weeks of gestation. In patients presenting with a high risk of intra-amniotic infection between January 2011 and May 2013, piperacillin or cefmetazole + clindamycin (regimen 1 group; n = 11) was administered, whereas SBT/ABPC and AZM (regimen 2 group; n = 11) were administered in patients presenting a similar risk between June 2013 and May 2016.

RESULTS

The incidence of moderate or severe infant BPD in the regimen 2 group was significantly lower than that in the regimen 1 group, even when adjusted for gestational age at the time of rupture of membrane, with an odds ratio (95% confidence interval) of 0.02 (1.8 × 10^-5 -0.33). The incidence of BPD and total days on mechanical ventilation were significantly lower in the regimen 2 group than in the regimen 1 group. No significant differences were seen in other morbidities.

CONCLUSION

In patients with pPROM between 22 and 27 weeks of gestation, the administration of SBT/ABPC and AZM may improve the perinatal outcomes.

Type II restriction modification system in Ureaplasma parvum OMC-P162 strain

Ureaplasma parvum serovar 3 strain, OMC-P162, was isolated from the human placenta of a preterm delivery at 26 weeks’ gestation. In this study, we sequenced the complete genome of OMC-P162 and compared it with other serovar 3 strains isolated from patients with different clinical conditions. Ten unique genes in OMC-P162, five of which encoded for hypothetical proteins, were identified. Of these, genes UPV_229 and UPV_230 formed an operon whose open reading frames were predicted to code for a DNA methyltransferase and a hypothetical protein, respectively. DNA modification analysis of the OMC-P162 genome identified N4-methylcytosine (m4C) and N6-methyladenine (m6A), but not 5-methylocytosine (m5C). UPV230 recombinant protein displayed endonuclease activity and recognized the CATG sequence, resulting in a blunt cut between A and T. This restriction enzyme activity was identical to that of the cultivated OMC-P162 strain, suggesting that this restriction enzyme was naturally expressed in OMC-P162. We designated this enzyme as UpaP162. Treatment of pT7Blue plasmid with recombinant protein UPV229 completely blocked UpaP162 restriction enzyme activity. These results suggest that the UPV_229 and UPV_230 genes act as a type II restriction-modification system in Ureaplasma OMC-P162.

Vaginal Ureaplasma species increase chorioamnionitis in very preterm infants with preterm premature rupture of the membranes at < 28 weeks of gestation

Our aim was to investigate the association between vaginal Ureaplasma species (spp.) and the subsequent occurrence of chorioamnionitis (CAM), perinatal death, neonatal morbidity, and long-term neurodevelopmental impairments (NDIs) at 3 years of age. We analyzed 55 pregnant women with singleton pregnancy who had preterm premature rupture of the membranes (pPROM) at < 28⁺⁰ weeks of gestation, and delivered between 22⁺⁰ and 31⁺⁶ weeks at our tertiary hospital in 2007-2016. NDIs were defined as either cerebral palsy or developmental delay evaluated at 1.5 and/or 3 years old. The presence of Ureaplasma spp. and Mycoplasma hominis were evaluated using urea-arginine broth and Mycoplasma PPLO Agar. The presence of Ureaplasma spp. in the vagina was positive in 41%. Vaginal Ureaplasma spp. was a significant risk factor for CAM; however, it was not significantly associated with the occurrence of perinatal death, pulmonary hypoplasia, respiratory distress syndrome, transient tachypnea of the newborn, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia defined as oxygen required and occasional ventilatory assistance required at week 36 as modified (BPD₃₆), or NDIs. The crude odds ratio (95% confidence interval) of Ureaplasma spp. for the occurrence of CAM was 9.5 (1.10-82) (p = 0.041). In very preterm birth infants with pPROM, CAM, BPD₃₆, and NDIs occurred in 78, 60, and 36%, respectively. Vaginal Ureaplasma spp. was a significant risk factor for CAM in very preterm birth infants with pPROM. The incidences of BPD₃₆ and NDIs in such infants were very high, nearing 3/5 and 1/3, respectively.

Infection-induced thrombin production: a potential novel mechanism for preterm premature rupture of membranes (PPROM)

BACKGROUND

Preterm premature rupture of membranes is a leading contributor to maternal and neonatal morbidity and death. Epidemiologic and experimental studies have demonstrated that thrombin causes fetal membrane weakening and subsequently preterm premature rupture of membranes. Although blood is suspected to be the likely source of thrombin in fetal membranes and amniotic fluid of patients with preterm premature rupture of membranes, this has not been proved. Ureaplasma parvum is emerging as a pathogen involved in prematurity, which includes preterm premature rupture of membranes; however, until now, prothrombin production that has been induced directly by bacteria in fetal membranes has not been described.

OBJECTIVE

This study was designed to investigate whether Ureaplasma parvum exposure can induce prothrombin production in fetal membranes cells.

STUDY DESIGN

Primary fetal membrane cells (amnion epithelial, chorion trophoblast, and decidua stromal) or full-thickness fetal membrane tissue explants from elective, term, uncomplicated cesarean deliveries were harvested. Cells or tissue explants were infected with live Ureaplasma parvum (1×10⁵, 1×10⁶ or 1×10⁷ colony-forming units per milliliter) or lipopolysaccharide (Escherichia coli J5, L-5014; Sigma Chemical Company, St. Louis, MO; 100 ng/mL or 1000 ng/mL) for 24 hours. Tissue explants were fixed for immunohistochemistry staining of thrombin/prothrombin. Fetal membrane cells were fixed for confocal immunofluorescent staining of the biomarkers of fetal membrane cell types and thrombin/prothrombin. Protein and messenger RNA were harvested from the cells and tissue explants for Western blot or quantitative reverse transcription polymerase chain reaction to quantify thrombin/prothrombin protein or messenger RNA production, respectively. Data are presented as mean values ± standard errors of mean. Data were analyzed using 1-way analysis of variance with post hoc Dunnett's test.

RESULTS

Prothrombin production and localization were confirmed by Western blot and immunostainings in all primary fetal membrane cells and tissue explants. Immunofluorescence observations revealed a perinuclear localization of prothrombin in amnion epithelial cells. Localization of prothrombin in chorion and decidua cells was perinuclear and cytoplasmic. Prothrombin messenger RNA and protein expression in fetal membranes were increased significantly by Ureaplasma parvum, but not lipopolysaccharide, treatments in a dose-dependent manner. Specifically, Ureaplasma parvum at a dose of 1×10⁷ colony-forming units/mL significantly increased both prothrombin messenger RNA (fold changes in amnion: 4.1±1.9; chorion: 5.7±4.2; decidua: 10.0±5.4; fetal membrane: 9.2±3.0) and protein expression (fold changes in amnion: 138.0±44.0; chorion: 139.6±15.1; decidua: 56.9±29.1; fetal membrane: 133.1±40.0) compared with untreated control subjects. Ureaplasma parvum at a dose of 1×10⁶ colony-forming units/mL significantly up-regulated prothrombin protein expression in chorion cells (fold change: 54.9±5.3) and prothrombin messenger RNA expression in decidua cells (fold change: 4.4±1.9).

CONCLUSION

Our results demonstrate that prothrombin can be produced directly by fetal membrane amnion, chorion, and decidua cells. Further, prothrombin production can be stimulated by Ureaplasma parvum exposure in fetal membranes. These findings represent a potential novel underlying mechanism of Ureaplasma parvum-induced rupture of fetal membranes.

Ureaplasma isolates stimulate pro-inflammatory CC chemokines and matrix metalloproteinase-9 in neonatal and adult monocytes

Being generally regarded as commensal bacteria, the pro-inflammatory capacity of Ureaplasma species has long been debated. Recently, we confirmed Ureaplasma–driven pro-inflammatory cytokine responses and a disturbance of cytokine equilibrium in primary human monocytes in vitro. The present study addressed the expression of CC chemokines and matrix metalloproteinase-9 (MMP-9) in purified term neonatal and adult monocytes stimulated with serovar 8 of Ureaplasma urealyticum (Uu) and serovar 3 of U. parvum (Up). Using qRT-PCR and multi-analyte immunoassay, we assessed mRNA and protein expression of the monocyte chemotactic proteins 1 and 3 (MCP-1/3), the macrophage inflammatory proteins 1α and 1β (MIP-1α/β) as well as MMP-9. For the most part, both isolates stimulated mRNA expression of all given chemokines and MMP-9 in cord blood and adult monocytes (p<0.05 and p<0.01). These results were paralleled by Uu and Up-induced secretion of MCP-1 protein in both cells (neonatal: p<0.01, adult: p<0.05 and p<0.01). Release of MCP-3, MIP-1α, MIP-1β and MMP-9 was enhanced upon exposure to Up (neonatal: p<0.05, p<0.01 and p<0.001, respectively; adult: p<0.05). Co-stimulation of LPS-primed monocytes with Up increased LPS-induced MCP-1 release in neonatal cells (p<0.05) and aggravated LPS-induced MMP-9 mRNA in both cell subsets (neonatal: p<0.05, adult: p<0.01). Our results document considerable expression of pro-inflammatory CC chemokines and MMP-9 in human monocytes in response to Ureaplasma isolates in vitro, adding to our previous data. Findings from co-stimulated cells indicate that Ureaplasma may modulate monocyte immune responses to a second stimulus.

Ureaplasma Species Differentially Modulate Pro- and Anti-Inflammatory Cytokine Responses in Newborn and Adult Human Monocytes Pushing the State Toward Pro-Inflammation

Background:Ureaplasma species have been associated with chorioamnionitis and preterm birth and have been implicated in the pathogenesis of neonatal short and long-term morbidity. However, being mostly commensal bacteria, controversy remains on the pro-inflammatory capacity of Ureaplasma. Discussions are ongoing on the incidence and impact of prenatal, perinatal, and postnatal infection. The present study addressed the impact of Ureaplasma isolates on monocyte-driven inflammation. Methods: Cord blood monocytes of term neonates and adult monocytes, either native or LPS-primed, were cultured with Ureaplasma urealyticum (U. urealyticum) serovar 8 (Uu8) and Ureaplasma parvum serovar 3 (Up3). Using qRT-PCR, cytokine flow cytometry, and multi-analyte immunoassay, we assessed mRNA and protein expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-8, IL-12p40, IL-10, and IL-1 receptor antagonist (IL-1ra) as well as Toll-like receptor (TLR) 2 and TLR4. Results: Uu8 and Up3 induced mRNA expression and protein release of TNF-α, IL-1β and IL-8 in term neonatal and adult monocytes (p < 0.01 and p < 0.05). Intracellular protein expression of TNF-α, IL-1β and IL-8 in Ureaplasma-stimulated cells paralleled those results. Ureaplasma-induced cytokine levels did not significantly differ from LPS-mediated levels except for lower intracellular IL-1β in adult monocytes (Uu8: p < 0.05). Remarkably, ureaplasmas did not induce IL-12p40 response and promoted lower amounts of anti-inflammatory IL-10 and IL-1ra than LPS, provoking a cytokine imbalance more in favor of pro-inflammation (IL-1β/IL-10, IL-8/IL-10 and IL-8/IL-1ra: p < 0.01, vs. LPS). In contrast to LPS, both isolates induced TLR2 mRNA in neonatal and adult cells (p < 0.001 and p < 0.05) and suppressed TLR4 mRNA in adult monocytes (p < 0.05). Upon co-stimulation, Uu8 and Up3 inhibited LPS-induced intracellular IL-1β (p < 0.001 and p < 0.05) and IL-8 in adult monocytes (p < 0.01), while LPS-induced neonatal cytokines were maintained or aggravated (p < 0.05). Conclusion: Our data demonstrate a considerable pro-inflammatory capacity of Ureaplasma isolates in human monocytes. Stimulating pro-inflammatory cytokine responses while hardly inducing immunomodulatory and anti-inflammatory cytokines, ureaplasmas might push monocyte immune responses toward pro-inflammation. Inhibition of LPS-induced cytokines in adult monocytes in contrast to sustained inflammation in term neonatal monocytes indicates a differential modulation of host immune responses to a second stimulus. Modification of TLR2 and TLR4 expression may shape host susceptibility to inflammation.

Rapid and simple detection of Ureaplasma species from vaginal swab samples using a loop-mediated isothermal amplification method

PROBLEM

Ureaplasma species occasionally cause chorioamnionitis and premature labor. We developed a novel assay employing a loop-mediated isothermal amplification (LAMP) method to detect Ureaplasma parvum and Ureaplasma urealyticum.

METHOD OF STUDY

Loop-mediated isothermal amplification primers were designed to amplify Ureaplasma-specific ureaseB genes. Four U. parvum strains, 5 U. urealyticum strains and 14 reference bacterial species were evaluated. Forty-six vaginal swab samples were analyzed by LAMP, culture, and PCR.

RESULTS

Our LAMP primers were specific to each species and had no cross-reaction. Of 46 clinical specimens, the sensitivity, specificity, and positive and negative predictive values of the LAMP method were 100% (12/12), 100% (34/34), 100% (12/12), and 100% (34/34), respectively, whereas those of PCR were 66.7% (8/12), 100% (34/34), 100% (8/8), and 89.5% (34/38), respectively, compared to culture-based detection.

CONCLUSION

The LAMP detection method outperformed the culture and PCR methods. Early detection enables appropriate antibiotic selection for improved prenatal outcomes.

Chorioamnionitis: Is a major player in the development of bronchopulmonary dysplasia?

Chorioamnionitis is an inflammation in the fetal membranes or placenta. When chorioamnionitis develops, fetal lungs are exposed to inflammatory cytokines and mediators via amniotic fluid. Because inflammation plays a pivotal role in the development of bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, fetal lung inflammation induced by chorioamnionitis has been considered to be one of the major pathogenetic factors for BPD. Although there have been a number of studies that demonstrated the relationship between chorioamnionitis and BPD, there are still controversies on this issue. The controversies on the relationship between chorioamnionitis and BPD arise from not-unified definitions of chorioamnionitis and BPD, different study populations, and the proportion of contribution between inflammation and infectious microorganisms. The publication bias also contributes to the controversies. Clinical trials targeting chorioamnionitis or microorganisms that cause chorioamnionitis will answer on the actual relationship between chorioamnionitis and BPD and provide a novel prophylactic strategy against BPD based on that relationship.

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

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

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

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

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

Mollicutes in vaginal microbiology: Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Mycoplasma genitalium

Mycoplasma hominis was isolated in 1937 from the human genital tract, followed 17 years later by Ureaplasma urealyticum and 27 years after that by Mycoplasma genitalium. The first two proved relatively easy to culture but the latter required a polymerase chain reaction assay for further studies. In sexually mature women, M. hominis may be found in the vagina/cervix of about 20-50%, ureaplasmas in 40-80% and M. genitalium in 0-5%. Some heterogeneity has been found among strains of all these species, sufficient to divide ureaplasmas into two species, namely U. urealyticum and Ureaplasma parvum. Studies in female mice show that sex hormones have a profound influence on colonization, multiplication and persistence of mycoplasmas/ureaplasmas in the genital tract and provoke the question, unanswered, of whether there is such an effect in the human tract. In women, there is no evidence that any of the mycoplasmal species stimulate an inflammatory vaginitis. M. hominis organisms increase hugely in number in the case of bacterial vaginosis (BV), and to a lesser extent so do ureaplasmas. Despite this, they have not been incriminated as a sole cause of BV. Evidence for the involvement of M. genitalium remains controversial. The strong association of BV with preterm birth raises the possibility that the genital mycoplasmas might play a part, but assurance that any do will be difficult to obtain. Detailed examination of the vaginal microbiome has not yet provided an answer.

Intracellular fate of Ureaplasma parvum entrapped by host cellular autophagy

Genital mycoplasmas, including Ureaplasma spp., are among the smallest human pathogenic bacteria and are associated with preterm birth. Electron microscopic observation of U. parvum showed that these prokaryotes have a regular, spherical shape with a mean diameter of 146 nm. U. parvum was internalized into HeLa cells by clathrin‐mediated endocytosis and survived for at least 14 days around the perinuclear region. Intracellular U. parvum reached endosomes in HeLa cells labeled with EEA1, Rab7, and LAMP‐1 within 1 to 3 hr. After 3 hr of infection, U. parvum induced the cytosolic accumulation of galectin‐3 and was subsequently entrapped by the autophagy marker LC3. However, when using atg7^−/−MEF cells, autophagy was inadequate for the complete elimination of U. parvum in HeLa cells. U. parvum also colocalized with the recycling endosome marker Rab11. Furthermore, the exosomes purified from infected HeLa cell culture medium included U. parvum. In these purified exosomes ureaplasma lipoprotein multiple banded antigen, host cellular annexin A2, CD9, and CD63 were detected. This research has successfully shown that Ureaplasma spp. utilize the host cellular membrane compartments possibly to evade the host immune system.

The Human Ureaplasma Species as Causative Agents of Chorioamnionitis

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

Coexistence of Ureaplasma and chorioamnionitis is associated with prolonged mechanical ventilation

BACKGROUND

Both histologic chorioamnionitis (HCAM) and Ureaplasma infection are considered important contributors to perinatal lung injury. We tested the hypothesis that coexistence of maternal HCAM and perinatal Ureaplasma exposure increases the risk of prolonged mechanical ventilation in extremely low-birthweight (ELBW) infants.

METHODS

A retrospective cohort study was carried out of all ELBW infants born between January 2008 and December 2013 at a single academic center. Placental pathology and gastric fluid Ureaplasma data were available for all infants. Culture and polymerase chain reaction were used to detect Ureaplasma in gastric fluid. Prolonged mechanical ventilation was defined as mechanical ventilation that began within 28 days after birth and continued.

RESULTS

Of 111 ELBW infants enrolled, 84 survived beyond 36 weeks of postmenstrual age (PMA) and were included in the analysis. Eighteen infants (21.4%) had both HCAM and Ureaplasma exposure. Seven infants (8.3%) required mechanical ventilation beyond 36 weeks of PMA. Coexistence of HCAM and Ureaplasma in gastric fluid was significantly associated with prolonged mechanical ventilation after adjustment for gestational age, sex, mode of delivery, and use of macrolide antibiotics (OR, 8.7; 95%CI: 1.1-67.2).

CONCLUSIONS

Coexistence of maternal HCAM and perinatal Ureaplasma exposure significantly increases the risk of prolonged mechanical ventilation in ELBW infants.