Evidence of bacterial DNA presence in chorionic villi and amniotic fluid in the first and second trimester of pregnancy.

The sterile-womb dogma in uncomplicated pregnancy has been lively debated. Data regarding the in utero microbiome environment are based mainly on studies performed at the time of delivery. Aim: To determine whether human placenta and amniotic fluid are populated by a bacterial microbiota in the first and second trimesters of pregnancy. Materials & methods: We analyzed by next-generation sequencing method 24 and 29 samples from chorionic villus sampling (CVS) and amniocentesis (AC), respectively. The V3 region of the 16S rRNA gene was sequenced. Results: 37.5% of CVS and 14% of AC samples showed the presence of bacterial DNA. Conclusion: Our study suggests that bacterial DNA can be identified in the placenta and amniotic fluid during early prenatal life.

Acute Villitis and Intravascular Microorganisms in Fetal Vessels: A Case Report and Literature Review of an Unusual Histopathological Finding.

Optimal management of intrauterine infection to avoid serious adverse perinatal outcomes entails prompt administration of antibiotics and consideration of early delivery of the fetus to remove the focus of infection. We report an unusual case of preterm chorioamnionitis which did not improve with sensitive antibiotics, or delivery of the fetus, and ultimately required an emergency hysterectomy to save the mother's life. Interestingly, subsequent histopathological analysis of the post-hysterectomy specimen did not reveal myometrial necrosis or infectious microorganisms. The placental pathological examination, on the other hand, showed evidence of necrotising chorioamnionitis accompanied by a rarely reported lesion: acute villitis with abundant intravascular Escherichia coli, a finding which is strongly associated with fetal demise and adverse maternal outcomes.

Inflammasome signaling in human placental trophoblasts regulates immune defense against Listeria monocytogenes infection.

The human placenta is a dynamic organ that modulates physiological adaptations to pregnancy. To define the immunological signature of the human placenta, we performed unbiased profiling of secreted immune factors from human chorionic villi isolated from placentas at mid and late stages of pregnancy. We show that placental trophoblasts constitutively secrete the inflammasome-associated cytokines IL-1ß and IL-18, which is blocked by NLRP3 inflammasome inhibitors and occurs without detectable gasdermin D cleavage. We further show that placenta-derived IL-1ß primes monocytes for inflammasome induction to protect against Listeria monocytogenes infection. Last, we show that the human placenta responds to L. monocytogenes infection through additional inflammasome activation and that inhibition of this pathway sensitizes villi to infection. Our results thus identify the inflammasome as an important mechanism by which the human placenta regulates systemic and local immunity during pregnancy to defend against L. monocytogenes infection.

Evidence for contamination as the origin for bacteria found in human placenta rather than a microbiota.

Until recently the in utero environment of pregnant women was considered sterile. Recent high-sensitivity molecular techniques and high-throughput sequencing lead to some evidence for a low-biomass microbiome associated with the healthy placenta. Other studies failed to reveal evidence for a consistent presence of bacteria using either culture or molecular based techniques. Comparing conflicting "placental microbiome" studies is complicated by the use of varied and inconsistent protocols. Given this situation, we undertook an evaluation of the in utero environment sterility using several controlled methods, in the same study, to evaluate the presence or absence of bacteria and to explain contradictions present in the literature. Healthy pregnant women (n = 38) were recruited in three maternity wards. Placenta were collected after cesarean section with or without Alexis® and vaginal delivery births. For this study we sampled fetal membranes, umbilical cord and chorionic villi. Bacterial presence was analyzed using bacterial culture and qPCR on 34 fetal membranes, umbilical cord and chorionic villi samples. Shotgun metagenomics was performed on seven chorionic villi samples. We showed that the isolation of meaningful quantities of viable bacteria or bacterial DNA was possible only outside the placenta (fetal membranes and umbilical cords) highlighting the importance of sampling methods in studying the in utero environment. Bacterial communities described by metagenomics analysis were similar in chorionic villi samples and in negative controls and were dependent on the database chosen for the analysis. We conclude that the placenta does not harbor a specific, consistent and functional microbiota.

Analysis of the capacity of Salmonella enterica Typhimurium to infect the human Placenta.

INTRODUCTION: Salmonella species are gram-negative facultative intracellular bacteria that are common causes of foodborne illness in North America. Infections by Salmonella during pregnancy are a significant cause of fetal loss in domestic livestock, and fetal and maternal mortality in mice. Furthermore, Salmonella infection is associated with miscarriage, stillbirth and preterm birth in pregnant women. Despite these collective associations, the extent to which Salmonella can infect the human placenta has not been investigated. METHODS: Human placental villous explants from several gestational ages were exposed to Salmonella enterica serovar Typhimurium (STm) ex vivo. Infection was assessed by colony forming unit assay and whole mount immunofluorescence (WMIF). RESULTS: Viable bacteria were recovered from placental villous explants of all gestational ages tested, but the bacterial burden was highest in 1st trimester explants. Bacterial numbers did not change appreciably with time post-infection in explants from any gestational age examined, suggesting that STm does not proliferate in placental villi. Exposure of villous explants to STm strains defective for the type III secretion systems revealed that Salmonella pathogenicity island 1 is essential for optimal invasion. In contrast to placental explants, STm infected and proliferated within villous cytotrophoblast cells isolated from term placentas. WMIF demonstrated that STm was restricted primarily to the syncytiotrophoblast layer in infected placentas. DISCUSSION: Our study demonstrates that STm can invade into the syncytiotrophoblast but does not subsequently proliferate. Thus, the syncytiotrophoblast may function as a barrier to STm infection of the fetus.

Spectrum of Changes Seen With Placental Intravascular Organisms.

Fetal bacterial infections are a common cause of fetal/neonatal morbidity and mortality. The pathologic correlates of congenital bacterial infection include acute chorioamnionitis, acute villitis, and acute intervillositis. The strength of the association of congenital bacterial infection differs among these pathologies. Acute chorioamnionitis results usually from an ascending infection, and damage to the fetus is thought to be cytokine driven rather than damage secondary to bacteremia. Acute villitis is strongly associated with fetal sepsis due to congenital infections. A much less common variant on acute villitis pattern has been described with additional presence of bacteria in the fetal capillaries of the chorionic villi. We describe the spectrum of bacteria that would induce this unique pattern. The histological archives were searched from 2 institutions for cases with intravascular bacteria present in the villous capillaries of the placenta. Thirteen cases were identified, of which 11 cases had acute chorioamnionitis and all cases showed an acute villitis. Eight cases had Escherichia coli identified and 3 cases had Group B Streptococcus. All cases were associated with fetal death. In 9 cases, the mother showed signs of a significant infection including 1 maternal death. We conclude that finding intravascular bacteria is a serious complication of congenital infection with serious fetal and maternal sequela.

Acute Placental Villitis as Evidence of Fetal Sepsis: An Autopsy Case Report.

Acute placental villitis is very rare and believed to reflect overwhelming fetal sepsis in utero, commonly caused by Escherichia coli or group B streptococci. We present a case of intrauterine fetal death associated with acute placental villitis and acute necrotizing chorioamnionitis by early-onset group B streptococcal infection. A 36-year-old woman presented with decreased fetal movement and fever at 21 weeks of gestation. Ultrasound demonstrated intrauterine fetal death. After delivery, the placenta revealed multifocal neutrophilic infiltration in chorionic villi, most prominently beneath the trophoblast basement membrane, which was also accompanied by acute necrotizing chorioamnionitis. Gram-positive microorganisms were detected in villous vessels as well as in the major organs of the fetus, which was consistent with Streptococcus agalactiae (group B) cultured from maternal blood. Acute placental villitis should be recognized as evidence of fetal sepsis that often has lethal clinical outcome, as compared to intra-amniotic infection associated with acute chorioamnionitis alone.

[DYNAMICS OF CHANGES IN THE NUMERICAL DENSITY OF PLACENTAL MACROPHAGES DURING UROGENITAL INFECTION IN EARLY PREGNANCY].

The changes in the numerical density of macrophages of maternal (basal decidua) and fetal (Kashchenko-Hofbauer cells) origin were studied in the placenta of women with opportunistic (Ureaplasma urealyticum and Mycoplasma hominis) and pathogenic (Chlamydia trachomatis) urogenital microflora. Histological study of placenta was performed and CD68-immunoreactive cells were detected immunohistochemically in the basal decidua and in the chorionic villi obtained during artificial abortions for non-medical reasons in the 6-8th week of pregnancy (n=136). The results showed no changes in the numerical density of macrophages of maternal origin and a significant decrease in the numerical density of macrophages in the stroma of the chorionic villi, which was associated in Chlamydial infection with a delayed, and in Ureaplasma and Mycoplasma infection - with an accelerated development of the villous tree.

PI3-kinase activation is critical for host barrier permissiveness to Listeria monocytogenes.

Invasion of nonphagocytic cells, a critical property of Listeria monocytogenes (Lm) that enables it to cross host barriers, is mediated by the interaction of two bacterial surface proteins, InlA and InlB, with their respective receptors E-cadherin and c-Met. Although InlA-E-cadherin interaction is necessary and sufficient for Lm crossing of the intestinal barrier, both InlA and InlB are required for Lm crossing of the placental barrier. The mechanisms underlying these differences are unknown. Phosphoinositide 3-kinase (PI3-K) is involved in both InlA- and InlB-dependent pathways. Indeed, InlA-dependent entry requires PI3-K activity but does not activate it, whereas InlB-c-Met interaction activates PI3-K. We show that Lm intestinal target cells exhibit a constitutive PI3-K activity, rendering InlB dispensable for InlA-dependent Lm intestinal barrier crossing. In contrast, the placental barrier does not exhibit constitutive PI3-K activity, making InlB necessary for InlA-dependent Lm placental invasion. Here, we provide the molecular explanation for the respective contributions of InlA and InlB to Lm host barrier invasion, and reveal the critical role of InlB in rendering cells permissive to InlA-mediated invasion. This study shows that PI3-K activity is critical to host barrier permissiveness to microbes, and that pathogens exploit both similarities and differences of host barriers to disseminate.

Role of innate immunity in pregnant patients with vulvovaginal infections in the development of intrauterine infection in the newborn.

A total of 115 pregnant women were examined: 59 patients with opportunistic vulvovaginal infections and 56 without infection. Congenital immunity parameters (TLR-2, NF-κB, and IL-2 receptors in placental tissue) were studied by immunohistochemical methods. Realization of congenital infection was associated with activation of IL-6 receptors and TLR-2 in the placenta and an increase of NF-κB level. These changes seemed to reflect the strained status of congenital immunity and were responsible for the intensity of local inflammatory response.

Nanobacteria and psammoma bodies: ultrastructural observations in a case of pathological placental calcification.

Nanobacteria are controversial infectious agents with nanometric size, the capacity to nucleate hydroxyapatite and grow in culture, and present in human diseases associated with calcification and psammoma bodies. The authors report a case of pathological placental calcifications associated with nanobacteria. Electron microscopy and electron energy loss spectroscopy imaging were used to recognize 160-nm-sized calcium-free bodies mainly presenting as extracellular fibrillary tangles and 500-nm-sized calcified bodies; they encrusted the syncito-trophoblast basal membrane and aggregated into miniaturized psammoma bodies. Nanobacteria may be composed of a prionoid protein with self-assembling and self-propagating abilities whose growth is associated with the formation of psammoma bodies.

Placental intravascular organisms: a case report.

Ascending amniotic fluid bacterial infection is a cause of perinatal morbidity and mortality. A diagnosis of amniotic cavity infection can be inferred by documenting maternal (acute chorioamnionitis) and/or fetal (chorionic plate vasculitis; umbilical vasculitis/funisitis) inflammatory response. A definitive diagnosis of intrauterine/neonatal sepsis as a cause of stillbirth requires positive blood cultures obtained at postmortem examination. However, if postmortem examination is not performed, acute chorioamnionitis with/without fetal inflammatory response cannot be classified as a cause of demise. We present a case of intrauterine demise associated with acute chorioamnionitis, villitis, and intervillositis of the placenta. Although postmortem examination was denied, a conclusive diagnosis of intrauterine sepsis could be rendered by demonstration of gram-positive cocci within fetal vessels of umbilical cord, chorionic plate, and stem villi. This report highlights the importance of identification of placental intravascular organisms as unequivocal evidence of fetal sepsis, especially in cases where cultures cannot be obtained.

Placental Cryptococcus neoformans infection without neonatal disease: case report and review of the literature.

We report placental cryptococcosis in a woman with multidrug resistant human immunodeficiency virus (HIV) infection. She received antifungal therapy for cryptococcal meningitis prior to delivery. Cesarean section was performed with delivery of a single full-term male infant. There was no evidence of HIV or cryptococcal infection in the infant. The placenta grossly showed multiple white nodules. Microscopically, numerous encapsulated budding yeasts, morphologically consistent with cryptococci, were identified in the intervillous space and, to a lesser extent, in the chorionic villi. Cryptococcal infections are not uncommon, but only 2 cases of placental cryptococcosis have been reported. Our case is the 1st account documenting cryptococcal organisms within the chorionic villi, and yet there was no evidence of infection in the infant. Mother-to-fetal transmission of cryptococcal infection is not well defined. We review the literature and discuss its possible mechanisms.

Immunohistochemical study of the morphological changes in placental villi from fetal membranes infectious disease.

UNLABELLED: Many types of infection cause placental changes but sometimes the etiological cause may be difficult to prove. Infections may ascend from endocervical canal or they may reach placenta hematogenously through the maternal blood. Typically, placenta of "the amnionic sac infection syndrome" is an immature placenta. Complex cellular mechanisms are involved in all types of infection that often are associated with placental insufficiency. OBJECTIVES: The aim of this study was to evaluate cellular changes induced by the hypoxic conditions due to infectious disease in the placental villous structures, especially in the trophoblast layer and vascular bed. MATERIAL AND METHODS: In order to label the trophoblast layer we used anti-cytokeratin cocktail AE1/AE3. Antibodies anti-VEGF and anti-c-ErbB4 were used for the evaluation of tissue response under hypoxic conditions and its involvement in villous remodeling. RESULTS: Chorion villi from placentas with histopathological features of insufficiency due to infectious etiology show an intense immunostaining for VEGF in the trophoblast, vessel walls and some stromal cells, namely Hofbauer cells. Villous trophoblast from the infected placenta expresses c-ErbB4 receptor. CONCLUSIONS: Overexpression of VEGF and c-ErbB4 is needed for the involvement of trophoblast layer in villous remodeling processes in order to maintain placental functionality under the effects of the inflammatory cascade.

Bacterial etiology for chronic villitis is not supported by polymerase chain reaction for 16S rRNA DNA.

Chronic villitis is characterized by chorionic villi infiltrated by lymphocytes, histiocytes, and sometimes plasma cells. In a small percentage of cases, an infectious agent can be demonstrated within areas of chronic villitis. However, the pathogenesis of most lesions is idiopathic. Chronic villitis may represent the direct spread of chronic endometrial infection by bacterial organisms that are particularly problematic for culture. To test this hypothesis, polymerase chain reaction (PCR) using primers for the universal bacterial 16S rRNA DNA was performed on DNA extracted from areas of chronic villitis selected from placentas in the Yale Pathology database. Specific areas of chronic villitis were first confirmed by examination of sections stained with hematoxylin and eosin and then removed from archived paraffin blocks. Control tissue spiked with known bacterial counts was also prepared to test the sensitivity of the experiment. All tissue was deparaffinized, dehydrated, and digested with proteinase K. DNA extraction was performed with the Gentra Puregene kit. PCR was done using primers p11 and p13 for the 16S rRNA DNA. The 233-bp amplified target product was identified by agarose gel electrophoresis. Nineteen specimens with multifocal chronic villitis without confinement to anchoring villi were studied. None of the chronic villitis specimens had a demonstrable product using the PCR primers for 16S rRNA DNA, despite adequate DNA in the samples and controls. The assay was sensitive down to approximately 1500 bacteria per specimen. In conclusion, these data do not support a bacterial etiology for chronic villitis.

[Morphofunctional placental characteristics in pregnant women with chronic pyelonephritis and urogenital chlamydia infection]. / Morfofunktsional'naia kharakteristika platsenty u beremennykh s khronicheskim pielonefritom i urogenital'nym khlamidiozom.

Morphological features of the placenta were studied in women with chronic pyelonephritis and urogenital chlamydial infection. There was an appreciable amount of chaotic sclerotic villi and symplastic nephroses reflecting compensatory-adaptive processes. Morphometric study of the afterbirths has shown that placenta affected with urogenital infection has large area of the intervillous space and small area of chorionic villi involved in gas exchange, supply of nutrients and other components to the fetus.

Possible role of bacterial and viral infections in miscarriages.

OBJECTIVE: To determine the role of infections in miscarriages. Chorionic villi from aborted material were subjected to cytogenetic evaluation and analyzed for the presence of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, human cytomegalovirus (HCMV), adeno-associated virus (AAV), and human papillomaviruses (HPV). DESIGN: Retrospective study. SETTING: University hospital and academic research institution. MAIN OUTCOME MEASURE(S): Karyotyping and detection of bacterial and viral DNA by means of polymerase chain reaction (PCR) in placenta specimens. RESULT(S): In 54 (50%) of 108 samples the karyotype was normal, in 38 (35%) samples it was abnormal, and in 16 (15%) samples karyotype was undetermined. No U. urealyticum, M. hominis, HCMV, or AAV-2 DNA was detected, while C. trachomatis DNA was detected in one (1%) and HPV DNA in eight (7%) samples. No significant correlation of HPV-positive findings with karyotype status was established. CONCLUSION(S): Our findings do not support a role of C. trachomatis, U. urealyticum, M. hominis, HCMV, or AAV infections in miscarriages during the first trimester of pregnancy. However, further investigation should be made to determine a possible involvement of HPVs in the development of genetic abnormalities of the fetus and in miscarriages.

Villitis of known origin: varicella and toxoplasma.

Chronic villitis is a common condition in human placentae. In some cases an infectious cause can be demonstrated, such as infection with cytomegalovirus and rubella virus. Most often it is of unknown aetiology, the so-called VUE (villitis of unknown aetiology). We describe two cases with identification of specific infectious agents, each demonstrating previously unreported findings, i.e. persistent varicella antigen in the villi in case 1, and presence of toxoplasma cysts in Wharton's jelly in case 2. The identification of the pathogens, varicella virus and toxoplasma, would easily have been overlooked in routine study of the placenta and were possible because of clinical suspicion.

A new type of fulminant group A streptococcal infection in obstetric patients: report of two cases.

A new type of fulminant group A streptococcal infection in obstetric patients is described. The illness occurs in late stage of pregnancy, and is preceded by an episode of upper respiratory tract infection. This is followed by sudden onset of septicemia, subsequent hematogenous infection of the myometrium by the bacteria, and development of acute purulent myometritis. Shock and multiorgan failure ensue rapidly. Prognosis of both the mother and fetus is very poor, as recognition of this serious condition is difficult until the late stage of the disease. This type of infection is entirely different from classical puerperal sepsis in that the illness starts before delivery, and that there was no evidence of ascending bacterial infections of the birth canal, such as acute endometritis or chorioamnionitis, in affected mothers. The underlying mechanism for this serious infection remains unknown.

Recurrent villitis of bacterial etiology.

Recurrent placental villitis is an uncommon clinicopathologic entity associated with a very high perinatal mortality rate. While most cases are idiopathic, other cases may have a treatable infectious cause. Here, a mother with recurrent fetal losses, each showing chronic villitis associated with rod shaped bacilli as demonstrated by Steiner stain, is presented. The key feature separating this and other similar cases from idiopathic villitis is a pleomorphic inflammatory infiltrate including lymphocytes, macrophages, eosinophils, plasma cells, and neutrophils.