Association of spontaneous abortion and Ureaplasma parvum detected in placental tissue

Mycoplasma DnaK increases DNA copy number variants in vivo

The human microbiota affects critical cellular functions, although the responsible mechanism(s) is still poorly understood. In this regard, we previously showed that Mycoplasma fermentans DnaK, an HSP70 chaperone protein, hampers the activity of important cellular proteins responsible for DNA integrity. Here, we describe a novel DnaK knock-in mouse model generated in our laboratory to study the effect of M. fermentans DnaK expression in vivo. By using an array-based comparative genomic hybridization assay, we demonstrate that exposure to DnaK was associated with a higher number of DNA copy number variants (CNVs) indicative of unbalanced chromosomal alterations, together with reduced fertility and a high rate of fetal abnormalities. Consistent with their implication in genetic disorders, one of these CNVs caused a homozygous Grid2 deletion, resulting in an aberrant ataxic phenotype that recapitulates the extensive biallelic deletion in the Grid2 gene classified in humans as autosomal recessive spinocerebellar ataxia 18. Our data highlight a connection between components of the human urogenital tract microbiota, namely Mycoplasmas, and genetic abnormalities in the form of DNA CNVs, with obvious relevant medical, diagnostic, and therapeutic implications.

Retrospective Analysis of Azithromycin-Resistant Ureaplasma urealyticum and Mycoplasma hominis Cervical Infection Among Pregnant Women

Purpose

Ureaplasma urealyticum and Mycoplasma hominis began to show resistance to azithromycin, a macrolide antibiotic commonly used in pregnancy. Unfortunately, there are few effective and safe drugs in the clinic for genital mycoplasmas in pregnant women. In the present study, we investigated the prevalence of azithromycin-resistant U. urealyticum and M. hominis infections in pregnant women. The secondary research objects were possible influencing factors and consequences of insensitive Mycoplasma infection.

Patients and methods

A retrospective analysis was carried out in pregnant women who underwent cervical Mycoplasma culture between October 2020 and October 2021 at a large general hospital in eastern China. The sociological characteristics and clinical information of these women were collected and analyzed.

Results

A total of 375 pregnant women were enrolled, and 402 cultured mycoplasma specimens were collected. Overall, 186 (49.60%) patients tested positive cervical Mycoplasma infection, and 37 (9.87%) had infections caused by azithromycin-resistant Mycoplasma. In total, 39 mycoplasma samples were insensitive to azithromycin in vitro, also showing extremely high resistance to erythromycin, roxithromycin, and clarithromycin. Azithromycin was the only antibiotic used in women with Mycoplasma cervical infection, regardless of azithromycin resistance in vitro. Statistical results showed that azithromycin-resistant cervical Mycoplasma infection in pregnant women was unrelated to age, body mass index (BMI), gestational age, number of embryos, and assisted reproductive technology (ART) use, but led to a significantly increased incidence of adverse pregnancy outcomes (spontaneous abortion (SA), preterm birth (PTB), preterm prelabor rupture of membranes (PPROM), and stillbirth).

Conclusion

Azithromycin-resistant U. urealyticum and M. hominis cervical infections are relatively common during pregnancy, and can increase the risk of adverse pregnancy outcomes; however, there is currently a lack of safe and effective drug treatments. Herein, we show that azithromycin-resistant mycoplasma infection requires timely intervention.

Chorioamnionitis secondary to Ureaplasma parvum infection: a case report

Objectives

Ureaplasma species are the most frequently isolated microorganisms in cases of spontaneous preterm labor, premature rupture of the membranes, or chorioamnionitis.

Case presentation

A woman at 28⁺⁶ weeks of gestation with no apparent history of interest presented at the hospital with contractions. Upon suspicion of chorioamnionitis, the patient was admitted for a low segment transverse cesarean section, which was completed without any complications. The patient was discharged at 7 days. The newborn remained stable and showed no clinical signs of infection. However, on suspicion of chorioamnionitis, empirical treatment with intravenous ampicillin (2 g every 6 h) and gentamicin (5 mg/kg once daily) was initiated. Samples of pharyngeal/tonsillar, ear, and anal/rectal exudates were collected. At 24 h, all samples were positive for Ureaplasma parvum. Empirical treatment was suspended, and treatment with intravenous azithromycin was initiated (12 mg once daily). Endocervical and placental exudates were also positive for U. parvum. Fifty-two days after birth, the newborn was discharged.

Conclusions

The relationship between Ureaplasma spp. colonization and perinatal disease seem to be clear. However, the high frequency of vaginal Ureaplasma spp. colonization and high rates of term labor among pregnant women with this colonization make further studies necessary.

The association between genital mycoplasma infection and spontaneous abortion: A systematic review and meta-analysis

Epidemiological findings on the association between genital mycoplasma infection (GMI) and spontaneous abortion are inconsistent. Therefore, this meta-analysis aims to determine whether mycoplasma infection during pregnancy increases the risk of spontaneous abortion. An electronic database search was conducted using China National Knowledge Infrastructure, Elsevier, PubMed, SinoMed, The Cochrane Library, and Wanfang Database from database establishment to October 2021. Sixteen case-controls and 3 prospective cohorts were included. The meta-analysis showed that GMI was positively associated with spontaneous abortion (odds ratio (OR) 2.35, 95% confidence interval (CI) 1.50, 3.67). Of them, case-control studies showed that the GMI proportion in the spontaneous abortion group was higher than that in the normal group (OR 2.13, 95% CI 1.33, 3.43); the cohort study showed that the spontaneous abortion rate in the GMI group was higher than those in non-infected groups (relative risk 5.17, 95% CI 2.07, 12.95; risk difference 0.18, 95% CI 0.09, 0.27). Each outcome indicator was relatively robust in the sensitivity analysis, and no significant publication bias was found in the funnel plots. Our data support that GMI during pregnancy increases the risk of spontaneous abortion. Thus, the monitoring and timely treatment of GMI before pregnancy of GMI are essential to decrease the risk of spontaneous abortion.

Adverse pregnancy and birth outcomes associated with Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum: a systematic review and meta-analysis

OBJECTIVES

Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum (genital mycoplasmas) commonly colonise the urogenital tract in pregnant women. This systematic review aims to investigate their role in adverse pregnancy and birth outcomes, alone or in combination with bacterial vaginosis (BV).

METHODS

We searched Embase, Medline and CINAHL databases from January 1971 to February 2021. Eligible studies tested for any of the three genital mycoplasmas during pregnancy and reported on the primary outcome, preterm birth (PTB) and/or secondary outcomes low birth weight (LBW), premature rupture of membranes (PROM), spontaneous abortion (SA) and/or perinatal or neonatal death (PND).Two reviewers independently screened titles and abstracts, read potentially eligible full texts and extracted data. Two reviewers independently assessed risks of bias using published checklists. Random effects meta-analysis was used to estimate summary ORs (with 95% CIs and prediction intervals). Multivariable and stratified analyses were synthesised descriptively.

RESULTS

Of 57/1194 included studies, 39 were from high-income countries. In meta-analysis of unadjusted ORs, M. hominis was associated with PTB (OR 1.87, 95% CI 1.49 to 2.34), PROM, LBW and PND but not SA. U. urealyticum was associated with PTB (OR 1.84, 95% CI 1.34 to 2.55), PROM, LBW, SA and PND. U. parvum was associated with PTB (1.60, 95% CI 1.12 to 2.30), PROM and SA. Nine of 57 studies reported any multivariable analysis. In two studies, analyses stratified by BV status showed that M. hominis and U. parvum were more strongly associated with PTB in the presence than in the absence of BV. The most frequent source of bias was a failure to control for confounding.

CONCLUSIONS

The currently available literature does not allow conclusions about the role of mycoplasmas in adverse pregnancy and birth outcomes, alone or with coexisting BV. Future studies that consider genital mycoplasmas in the context of the vaginal microbiome are needed.

PROSPERO REGISTRATION NUMBER

CRD42016050962.

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.

The evidence for placental microbiome and its composition in healthy pregnancies: A systematic review

OBJECTIVE

To assess the available scientific evidence regarding the placental microbial composition of a healthy pregnancy, the quality of this evidence, and the potential relation between placental and oral microbiome.

MATERIALS AND METHODS

Data sources: MEDLINE and EMBASE up to August 1, 2019.

STUDY ELIGIBILITY CRITERIA

Human subjects; healthy women; term deliveries; healthy normal birth weight; assessment of microorganisms (bacteria) in placental tissue; full research papers in English. The quality of the included studies was assessed by a modified Joanna Briggs Institute checklist for analytical cross-sectional studies.

RESULTS

57 studies passed the inclusion criteria. Of these, 33 had a high risk of quality bias (e.g., insufficient infection control, lack of negative controls, poor description of the healthy cases). The remaining 24 studies had a low (N = 12) to moderate (N = 12) risk of bias and were selected for in-depth analysis. Of these 24 studies, 22 reported microorganisms in placental tissues, where Lactobacillus (11 studies), Ureaplasma (7), Fusobacterium (7), Staphylococcus (7), Prevotella (6) and Streptococcus (6) were among the most frequently identified genera. Methylobacterium (4), Propionibacterium (3), Pseudomonas (3) and Escherichia (2), among others, although frequently reported in placental samples, were often reported as contaminants in studies that used negative controls.

CONCLUSIONS

The results support the existence of a low biomass placental microbiota in healthy pregnancies. Some of the microbial taxa found in the placenta might have an oral origin. The high risk of quality bias for the majority of the included studies indicates that the results of individual papers should be interpreted with caution.

The reproductive tract microbiota in pregnancy

The reproductive tract microbiota plays a crucial role in maintenance of normal pregnancy and influences reproductive outcomes. Microbe–host interactions in pregnancy remain poorly understood and their role in shaping immune modulation is still being uncovered. In this review, we describe the composition of vaginal microbial communities in the reproductive tract and their association with reproductive outcomes. We also consider strategies for manipulating microbiota composition by using live biotherapeutics, selective eradication of pathogenic bacteria with antibiotics and vaginal microbiota transplantation. Finally, future developments in this field and the need for mechanistic studies to explore the functional significance of reproductive tract microbial communities are highlighted.

Ureaplasma parvum alters the immune tolerogenic state in placental tissue and could cause miscarriage

OBJECTIVE

To study the inflammatory profile and genes involved in the response to bacterial infections in women who developed spontaneous abortion in the presence of Ureaplasma parvum.

DESIGN

Cross-sectional study.

SETTING

A maternal and child referral center.

PATIENT(S)

Eighty-nine women with spontaneous abortion and 20 women with normal vaginal delivery (control group) were studied.

INTERVENTION(S)

Samples of biopsied placental tissue were collected for Mollicutes detection.

MAIN OUTCOME MEASURE(S)

The samples were subjected to histologic analysis, immunohistochemical evaluation for macrophages and lymphocytes, cytokine quantification, and quantitative polymerase chain reaction array to evaluate the expression of 84 genes related to the innate and adaptive immune responses.

RESULT(S)

The presence of U. parvum in the abortion group was positively associated with the influx of polymorphonuclear cells in the placental tissue and increased concentrations of interleukin-6 and interleukin-12p70. U. parvum caused downregulation of genes involved in the immune response, such as attraction of immune cells, activation of an inflammatory response, T-helper cell 17 response activation, and activation of the complement system at the beginning and end of pregnancy.

CONCLUSION

The direct action of U. parvum on placental tissue altered the gestational tolerogenic state, reducing the immune response against pathogens and activating the extrinsic apoptotic pathway, causing spontaneous abortion.

A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle

The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.