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.

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.

[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.

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.

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.

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.

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.

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.

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.

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.

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.

Detection of the human cytomegalovirus gene in placental chronic villitis by polymerase chain reaction.

Placental chronic villitis was observed in 44 cases (2.12%) of 2,073 histologically examined placentas. Infiltrating lymphocytes in chronic villitis were determined by immunohistochemistry to be predominantly helper/inducer T cells. Detection of the cytomegalovirus (CMV) gene was performed on paraffin-embedded sections by polymerase chain reaction (PCR) using two different primers (CMV immediate early gene and CMV late antigen gp 64). Both CMV immediate early gene and late antigen gp 64 gene were detected in one case. Cytomegalovirus late antigen gp 64 gene was observed in only three cases. Among these four cases, the cytomegalic inclusion body was observed only in a single case with light microscopic examination. In two cases generalized CMV infection was manifested during the early infantile period and the patient died of the disease. The other two cases were asymptomatic. Our data suggest that approximately 9% of the cases of chronic villitis are caused by CMV infection, and most of them are difficult to detect morphologically. Detection of CMV gene by PCR using primers, especially late antigen gp 64 gene, is very useful for assessing the cause of placental chronic villitis.

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.

Absence of cytomegalovirus in gestational tissue in recurrent spontaneous abortion.

There have been conflicting reports regarding the association of cytomegalovirus (CMV) and recurrent spontaneous abortions. It is difficult to assess the role of CMV in the endometrium by histology alone, since the characteristic cytomegalic virocytes are often scarce or absent in this site. Our purpose was to use the polymerase chain reaction (PCR) to detect cytomegalovirus in gestational tissue of women with recurrent spontaneous abortions. DNA was extracted from 25 samples of paraffin-embedded, formalin-fixed gestational tissue from 21 women with at least three unexplained spontaneous abortions (mean, 3.4). DNA from an unstained paraffin section of each specimen was amplified using nested, multiplex PCR specific for the late antigen and the major immediate early genes of CMV. The assay used has a demonstrated level of sensitivity on the order of 10(-2) virocytes per square centimeter of 4-microM paraffin section. Intact DNA was successfully isolated from 21 specimens in 18 patients. Histologic features of CMV infection were completely absent from these cases, and none of these specimens contained evidence of cytomegalovirus DNA. These findings suggest that CMV infection of gestational tissue is not a common direct cause of recurrent spontaneous abortions.

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.

Immunohistochemical detection of Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of bovine placenta and fetal lung.

An immunohistochemical technique using a monoclonal antibody was evaluated as a diagnostic tool to specifically label Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of placenta and fetal lung from bovine abortions. Trichomonads were demonstrated in tissues from each of 12 abortions due to T. foetus and none of 15 abortions due to other or unidentified causes. Moderate to marked background staining occurred only in severely autolyzed tissues from T. foetus-infected fetuses. The antibody faintly labeled 1 of 3 other species of trichomonads (Trichomonas gallinae) but did not label other protozoa, bacteria, or fungi tested.

Detection of congenital cytomegalovirus infection by using chorionic villi of the early pregnancy and polymerase chain reaction.

OBJECTIVE: To detect congenital cytomegalovirus (CMV) infection of chorionic villi in early pregnancy. METHODS: Extraction of DNA of chorionic villi and amplification of the gene of major immediate-early (MIE) antigen of CMV using a polymerase chain reaction (PCR). RESULTS: Sixty-eight specimens of chorionic villi and 16 specimens were positive for CMV infection by PCR. The incidence of congenital CMV infection in the first trimester of pregnancy was 23.5%. CONCLUSIONS: The risk of transmission of CMV from mother to fetus in early pregnancy is very high and potential CMV carriers may transmit CMV to their fetus in early pregnancy.

[Placental aspergillosis: myth or reality? Apropos of a case with fetal death in utero]. / L'aspergillose placentaire: mythe ou réalité? A propos d'une observation avec mort foetale in utero.

The authors report an original case-history of massive aspergillosis of the placenta that occurred in a 24 year old primigravida who had had no previous history or clinical changes in pregnancy. It caused fetal death in utero with retention and maceration of the fetus. Macroscopic examination showed that the left lip was cleft and that the placenta was studded with isolated confluent diffuse whitish granulations. Histologic examination made us think that these appearances were those of aspergillar granulomas occurring even in the placental villi and intravillous spaces. Laboratory findings showed that there was Aspergillus Niger in the blood of the mother. A wide search of the literature failed to find any case in humans. On the other hand aspergillosis occurs frequently in animals causing intrauterine growth retardation and prematurity with abortion. There is great economic loss as a result. Why the animal placenta should be susceptible to infection of aspergillosis and how it acquires it is discussed! Finally the association of aspergillosis of the placenta with a cleft lip found in our case, is unique and one wonders if there is any relationship.

[Monitoring of maternal-fetal hepatitis B virus transmission by molecular hybridization technique].

Maternal venous blood (MB), umbilical blood (UB) and placental tissue (PT) were collected from 40 HBsAg positive mothers and their neonates, and also blood from 17 babies aged 3-6 months old of this group (BB). All samples were determined for hepatitis B virus (HBV) DNA by molecular hybridization technique using Bio-HBV DNA probe. The results showed: HBV DNA positive rate of MB was 35.0%, 47.5% for UB, 75.0% for PT and 29.4% for BB. 32 P-HBV DNA probe was also used to examine MB and PT. The positive rates of HBV DNA were 30.0% and 70.0% respectively. There was no significant difference between the results of the 2 probes. We considered: (1) With the rapid development of HBV detection technique, the detectable rate of intrauterine infection increases accordingly. (2) Besides transplacental infection, other transmission routes might be existed. (3) The detection of HBV DNA in UB, PT and in the blood of babies born by HBV DNA positive mother within 6 months old provides the reliable diagnosis. (4) HBV DNA molecular hybridization is an accurate and sensitive method for the diagnosis of HBV intrauterine infection.