Is Ureaplasma spp. the leading causative agent of acute chorioamnionitis in women with preterm birth?

Is there a placental microbiota? A critical review and re-analysis of published placental microbiota datasets

The existence of a placental microbiota is debated. The human placenta has historically been considered sterile and microbial colonization was associated with adverse pregnancy outcomes. Yet, recent DNA sequencing investigations reported a microbiota in typical human term placentas. However, this detected microbiota could represent background DNA or delivery-associated contamination. Using fifteen publicly available 16S rRNA gene datasets, existing data were uniformly re-analyzed with DADA2 to maximize comparability. While Amplicon Sequence Variants (ASVs) identified as Lactobacillus, a typical vaginal bacterium, were highly abundant and prevalent across studies, this prevalence disappeared after applying likely  DNA contaminant removal to placentas from term cesarean deliveries. A six-study sub-analysis targeting the 16S rRNA gene V4 hypervariable region demonstrated that bacterial profiles of placental samples and technical controls share principal bacterial ASVs and that placental samples clustered primarily by study origin and mode of delivery. Contemporary DNA-based evidence does not support the existence of a placental microbiota.ImportanceEarly-gestational microbial influences on human development are unclear. By applying DNA sequencing technologies to placental tissue, bacterial DNA signals were observed, leading some to conclude that a live bacterial placental microbiome exists in typical term pregnancy. However, the low-biomass nature of the proposed microbiome and high sensitivity of current DNA sequencing technologies indicate that the signal may alternatively derive from environmental or delivery-associated bacterial DNA contamination. Here we address these alternatives with a re-analysis of 16S rRNA gene sequencing data from 15 publicly available placental datasets. After identical DADA2 pipeline processing of the raw data, subanalyses were performed to control for mode of delivery and environmental DNA contamination. Both environment and mode of delivery profoundly influenced the bacterial DNA signal from term-delivered placentas. Aside from these contamination-associated signals, consistency was lacking across studies. Thus, placentas delivered at term are unlikely to be the original source of observed bacterial DNA signals.

Roles of the Microbiota of the Female Reproductive Tract in Gynecological and Reproductive Health

The microbiome of the female reproductive tract defies the convention that high biodiversity is a hallmark of an optimal ecosystem. Although not universally true, a homogeneous vaginal microbiome composed of species of Lactobacillus is generally associated with health, whereas vaginal microbiomes consisting of other taxa are generally associated with dysbiosis and a higher risk of disease. The past decade has seen a rapid advancement in our understanding of these unique biosystems. Of particular interest, substantial effort has been devoted to deciphering how members of the microbiome of the female reproductive tract impact pregnancy, with a focus on adverse outcomes, including but not limited to preterm birth. Herein, we review recent research efforts that are revealing the mechanisms by which these microorganisms of the female reproductive tract influence gynecologic and reproductive health of the female reproductive tract.

Predicting preterm birth based on vaginal microbiota assessment by real-time PCR in the first trimester

Detecting high risk of preterm birth (PB) early makes its prevention possible. The aim of the work was to develop a mathematical predictive model for assessing the risk of preterm birth based on a quantitative analysis of the vaginal microbiota in the first trimester of pregnancy. The study included 199 pregnant women, i.e. 41 pregnancies that ended in preterm birth, and 158 — in term birth. Vaginal microbiota was analyzed in all patients in the 1st trimester of pregnancy by quantitative real-time PCR (qPCR). The method of dicriminant analysis was used to develop a predictive model. A method for predicting PB was developed with the calculation of the PRIMA prognostic index (Premature Birth. Index Of Microbiological Analysis). If the value of PRIMA > 0 – the risk of premature birth is low, if PRIMA < 0 – the risk is high. The sensitivity and specificity of the method are respectively 70.7% and 79.75%, the effectiveness is 77.89%. Evaluation of vaginal microbiota in the 1st trimester makes it possible to identify a high-risk group of PB and perform timely preventive measures.

Relationship between Mollicutes and spontaneous abortion: An epidemiological analysis

BACKGROUND

Abortion is of great importance in public health, as it is among the main causes of maternal morbidity and mortality. In addition to sociodemographic- and lifestyle-related factors, studies have associated infections of the genital tract with higher rates of abortion. Therefore, the exacerbated presence and rise of Mollicutes in the genitourinary tract may be related to higher rates of abortion.

AIM

To perform an epidemiological analysis of women who had spontaneous abor-tions and placental colonization by Mollicutes in a maternity hospital.

METHODS

This cross-sectional study involved the collection of data and biological material from women hospitalized due to spontaneous abortion or term delivery. The sample consisted of 89 women who miscarried and 20 women who had full term pregnancy. Data collection was carried out in three stages: (1) Conducting research on the information and clinical data in medical records of patients hospitalized due to abortion; (2) Application of a semi-structured questionnaire to identify the patient's epidemiological profile and (3) Collection of placental tissue. Placental samples were collected after the curettage procedure (abortion) and after placental expulsion (delivery), both performed by an obstetrician. Microbial identification in the fragments was performed by real-time polymerase chain reaction. In this study, the following explanatory variables were considered: (1) Sociodemographic variables; (2) Variables related to access to health services; (3) Variables related to lifestyle; and (4) Variables related to sexual and reproductive health, all of which were used to perform descriptive, univariate and multivariate analyses.

RESULTS

In the final model, placental colonization by Mollicutes was independently associated with the variables age [odds ratio (OR) = 7.55; CI: 2.37-24.03] and menarche (OR = 3.43; CI: 1.03-11.44). In this investigation, the prevalence of Mollicutes colonization by at least one of the following three species: Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum in women who had spontaneous abortion was 73.0%. When comparing colonization between the two groups of participating women, there was an 8.12-fold risk of placental colonization by at least one Mollicutes species in the women who had an abortion, compared to those who completed pregnancy. The final multivariate analysis model revealed a statistically significant association between placental colonization by Mollicutes in abortion with the following variables: age, as women up to 29 years old had a 7.55-fold risk of spontaneous abortion, compared to those who were older than 29 years; menarche, where women who had menarche up to 13 years old had a 3.43-fold risk of miscarriage compared to those who had menarche over 13 years old; and a change in eating habits, after the discovery of pregnancy, was a protective factor (OR = 0.16).

CONCLUSION

These findings revealed a positive association between spontaneous abortion and placental colonization by Mollicutes. This indicates the need for further investigation of this issue, to guide decision-making for the prevention of abortion.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

Intra-Amniotic Infection with Ureaplasma parvum Causes Preterm Birth and Neonatal Mortality That Are Prevented by Treatment with Clarithromycin

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Multiple etiologies are associated with preterm birth; however, 25% of preterm infants are born to a mother with intra-amniotic infection, most commonly due to invasion of the amniotic cavity by Ureaplasma species. Much research has focused on establishing a link between Ureaplasma species and adverse pregnancy/neonatal outcomes; however, little is known about the taxonomy of and host response against Ureaplasma species. Here, we applied a multifaceted approach, including human samples, in vivo models, and in vitro manipulations, to study the maternal-fetal immunobiology of Ureaplasma infection during pregnancy. Furthermore, we investigated the use of clarithromycin as a treatment for this infection. Our research provides translational knowledge that bolsters scientific understanding of Ureaplasma species as a cause of adverse pregnancy/neonatal outcomes and gives strong evidence for the use of clarithromycin as the recommended treatment for women intra-amniotically infected with Ureaplasma species.

Intra-amniotic infection is strongly associated with adverse pregnancy and neonatal outcomes. Most intra-amniotic infections are due to Ureaplasma species; however, the pathogenic potency of these genital mycoplasmas to induce preterm birth is still controversial. Here, we first laid out a taxonomic characterization of Ureaplasma isolates from women with intra-amniotic infection, which revealed that Ureaplasma parvum is the most common bacterium found in this clinical condition. Next, using animal models, we provided a causal link between intra-amniotic inoculation with Ureaplasma species and preterm birth. Importantly, the intra-amniotic inoculation of Ureaplasma species induced high rates of mortality in both preterm and term neonates. The in vivo potency of U. parvum to induce preterm birth was not associated with known virulence factors. However, term-derived and preterm-derived U. parvum isolates were capable of inducing an intra-amniotic inflammatory response. Both U. parvum isolates invaded several fetal tissues, primarily the fetal lung, and caused fetal inflammatory response syndrome. This bacterium was also detected in the placenta, reproductive tissues, and most severely in the fetal membranes, inducing a local inflammatory response that was replicated in an in vitro model. Importantly, treatment with clarithromycin, a recently recommended yet not widely utilized antibiotic, prevented the adverse pregnancy and neonatal outcomes induced by U. parvum. These findings shed light on the maternal-fetal immunobiology of intra-amniotic infection.

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.

Infections complicating cesarean delivery

PURPOSE OF REVIEW

Cesarean sections are common surgical procedures performed in a healthy population and are unique because of a relatively high rate of postoperative infection. There have been many important advances in understanding the pathogenesis of infection and evaluation of interventions to prevent post cesarean section infections in the last few years. Our purpose in this review is to analyze these new data, discuss unanswered questions, and propose changes in standard of care.

RECENT FINDINGS

Wound closure techniques including subcuticular sutures and subcutaneous suturing have been shown to be effective at reducing surgical site infections. Wound dressings including negative pressure dressings likely do not decrease infection rates. The type, timing, and duration of preoperative prophylactic antibiotics, including adjunctive azithromycin for laboring women and multidose antibiotics in obese women, have also yielded mixed results. Our understanding of normal uterine microbiome and the impact of intrapartum antibiotics on the newborn is emerging.

SUMMARY

The pathogenesis of surgical site infections after Cesarean section is complex and multifactorial. Many interventions to reduce infections have been studied with varying degrees of effectiveness. Despite advances in the area, important questions remain unanswered.

Has doxycycline, in combination with anti-malarial drugs, a role to play in intermittent preventive treatment of Plasmodium falciparum malaria infection in pregnant women in Africa?

According to the World Health Organization (WHO), Plasmodium falciparum malaria during pregnancy is responsible for deleterious consequences for the mother and her child. The administration of intermittent preventive treatment (IPTp) with sulfadoxine–pyrimethamine (SP) at each antenatal care visit as early as 13 weeks of gestation until the time of delivery is a strategy that is currently recommended by WHO for the prevention of malaria in pregnancy. However, the emergence and the spread of the resistance to SP in Africa raise the question of the short-term effectiveness of the strategy. Dihydroartemisinin–piperaquine 120 mg/960 mg once a day for 3 consecutive days administered at least three times during the pregnancy might be an option for IPTp. The combination of 200 mg of doxycycline once a day for 3 consecutive days seems to be a good option to retard the emergence and the spread of resistance to artemisinin-based combination therapy (ACT) in Africa and improve the effectiveness of ACT in term of preterm births, neonatal morbidity and mortality. Contrary to preconceived ideas, scientific and medical data suggest that the risk of congenital malformations in the fetus or of tooth staining in infants whose mothers take doxycycline and hepatotoxicity during pregnancy is very low or non-existent. Additionally, the use of doxycycline during the first and second trimesters leads to an increase in gestational age at delivery, a decrease in the number of preterm births and a reduction in neonatal morbidity and mortality due to the beneficial antimicrobial activity of doxycycline against other infections during pregnancy. Furthermore, doxycycline has anti-malarial properties and is already recommended as prophylaxis for travellers and for treatment of falciparum malaria in combination with other anti-malarial drugs.

HPV infection and bacterial microbiota in the placenta, uterine cervix and oral mucosa

We investigated the association between HPV infection and bacterial microbiota composition in the placenta, uterine cervix and mouth in thirty-nine women. HPV DNA genotyping of 24 types was conducted using Multimetrix®. Microbiota composition was characterized by 16S rRNA gene sequencing. HPV DNA was detected in 33% of placenta, 23% cervical and 33% oral samples. HPV16 was the most frequent type in all regions. HPV infection was associated with higher microbiota richness (p = 0.032) in the mouth but did not influence microbial diversity or richness in other samples. HPV infection was associated with higher abundance of Lactobacillaceae (p = 0.0036) and Ureaplasma (LDA score > 4.0, p < 0.05) in the placenta, Haemophilus (p = 0.00058) and Peptostreptococcus (p = 0.0069) genus in the cervix and Selenomonas spp. (p = 0.0032) in the mouth compared to HPV negative samples. These data suggest altered bacterial microbiota composition in HPV positive placenta, cervix and mouth. Whether the changes in bacterial microbiota predispose or result from HPV remains to be determined in future studies.

Effect of Genital Sampling Site on the Detection and Quantification of Ureaplasma Species with Quantitative Polymerase Chain Reaction during Pregnancy

Objective. This study aimed to compare the qualitative and quantitative reproducibility of quantitative PCR (qPCR) for Ureaplasma species (Ureaplasma spp.) throughout pregnancy and according to the genital sampling site. Study Design. Between 5 and 14 weeks of gestation (T1), vaginal, fornix, and two cervical samples were taken. Sampling was repeated during the 2nd (T2) and 3rd (T3) trimester in randomly selected T1 positive and negative women. Qualitative and quantitative reproducibility were evaluated using, respectively, Cohen's kappa (κ) and interclass correlation coefficients (ICC) and repeated measures ANOVA on the log-transformed mean number of DNA copies for each sampling site. Results. During T1, 51/127 women were positive for U. parvum and 8 for U. urealyticum (4 patients for both). Sampling was repeated for 44/55 women at T2 and/or T3; 43 (97.7%) remained positive at the three timepoints. κ ranged between 0.83 and 0.95 and the ICC for cervical samples was 0.86. Conclusions. Colonization by Ureaplasma spp. seems to be very constant during pregnancy and vaginal samples have the highest detection rate.