Infections at the maternal-fetal interface: an overview of pathogenesis and defence.

Infections are a major threat to human reproductive health, and infections in pregnancy can cause prematurity or stillbirth, or can be vertically transmitted to the fetus leading to congenital infection and severe disease. The acronym 'TORCH' (Toxoplasma gondii, other, rubella virus, cytomegalovirus, herpes simplex virus) refers to pathogens directly associated with the development of congenital disease and includes diverse bacteria, viruses and parasites. The placenta restricts vertical transmission during pregnancy and has evolved robust mechanisms of microbial defence. However, microorganisms that cause congenital disease have likely evolved diverse mechanisms to bypass these defences. In this Review, we discuss how TORCH pathogens access the intra-amniotic space and overcome the placental defences that protect against microbial vertical transmission.

Current practices of management of maternal and congenital Cytomegalovirus infection during pregnancy after a maternal primary infection occurring in first trimester of pregnancy: Systematic review.

INTRODUCTION: Congenital CMV infection is the first worldwide cause of congenital viral infection but systematic screening of pregnant women and newborns for CMV is still debated in many countries. OBJECTIVES: This systematic review aims to provide the state of the art on current practices concerning management of maternal and congenital CMV infection during pregnancy, after maternal primary infection (PI) in first trimester of pregnancy. DATA SOURCES: Electronically searches on databases and hand searches in grey literature. STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS: Primary outcome was listing biological, imaging, and therapeutic management interventions in two distinct populations: population 1 are pregnant women with PI, before or without amniocentesis; population 2 are pregnant women with congenitally infected fetuses (after positive amniocentesis). Secondary outcome was pregnancy outcome in population 2. RESULTS: Out of 4,134 studies identified, a total of 31 studies were analyzed, with 3,325 pregnant women in population 1 and 1,021 pregnant women in population 2, from 7 countries (Belgium, France, Germany, Israel, Italy, Spain and USA). In population 1, ultrasound (US) examination frequency was 0.75/month, amniocentesis in 82% cases, maternal viremia in 14% and preventive treatment with hyperimmune globulins (HIG) or valaciclovir in respectively 14% and 4% women. In population 2, US examination frequency was 1.5/month, magnetic resonance imaging (MRI) in 44% cases at 32 weeks gestation (WG), fetal blood sampling (FBS) in 24% at 28 WG, and curative treatment with HIG or valaciclovir in respectively 9% and 8% patients. CONCLUSIONS: This systematic review illustrates management of maternal and congenital CMV during pregnancy in published and non-published literature, in absence of international consensus. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019124342.

Congenital infections in Hong Kong: beyond TORCH.

Congenital infections refer to a group of perinatal infections that are caused by pathogens transmitted from mother to child during pregnancy (transplacentally) or delivery (peripartum) which may have similar clinical presentations, including rash and ocular findings. TORCH is the acronym that covers these infections (toxoplasmosis, other [syphilis], rubella, cytomegalovirus, herpes simplex virus). Other important causes of intrauterine/perinatal infection include human immunodeficiency virus, varicella-zoster virus, Treponema pallidum, Zika virus, and parvovirus B19. This overview aims to describe various congenital infections beyond TORCH with a Hong Kong perspective. Intrauterine and perinatal infections are a major cause of in utero death and neonatal mortality, and an important contributor to childhood morbidity. A high index of suspicion for congenital infections and awareness of the prominent features of the most common congenital infections can help to facilitate early diagnosis, tailor appropriate diagnostic evaluation, and initiate appropriate early treatment. Intrauterine infections should be suspected in newborns with clinical features including microcephaly, seizures, cataract, hearing loss, congenital heart disease, hepatosplenomegaly, small for gestational age, and/or rash. Primary prevention of maternal infections during pregnancy is key to the prevention of congenital infection, and resources (if available) should focus on public health promotion and pre-marital counselling.

Key Infections in the Placenta.

Congenital infections are an important cause of morbidity and mortality worldwide, especially in low-income settings. This review discusses the main pathways of infections and associated adverse maternal and fetal outcomes, considering the TORCH pathogens, including Zika virus; the acronym stands for Toxoplasma gondii infection, other (Listeria monocytogenes, Treponema pallidum, and parvovirus B19, among others, including Zika virus), rubella virus, cytomegalovirus, and herpes simplex viruses type 1 and type 2.

Successful treatment of severe acute respiratory distress syndrome due to Group A streptococcus induced toxic shock syndrome in the third trimester of pregnancy-effectiveness of venoarterial extracorporeal membrane oxygenation: A case report.

We report a case of Group A streptococcal infection-induced toxic shock syndrome (GAS-TSS) with severe acute respiratory distress syndrome (ARDS), successfully treated with venoarterial extracorporeal membrane oxygenation (V-A ECMO). A 31-year-old woman was transferred due to high fever, continuous uterine contractions and fetal bradycardia at 31 weeks of gestation. She was in a shock status on arrival, and as fetal heart beat disappeared, we canceled the cesarean section and took priority in maternal rescue. At 21 h after the admission, pulseless ventricular tachycardia occurred, and V-A ECMO was introduced after defibrillation, which dramatically improved her respiratory and circulatory conditions. On the 3rd day, GAS was isolated from blood culture. The patient was freed from V-A ECMO on the 5th day and was discharged on the 25th day without permanent impairment. V-A ECMO should be considered as an effective therapeutic option against ARDS and circulation failure in GAS-TSS during pregnancy.

Congenital and perinatal infections.

Congenital and perinatal infections represent major causes of permanent disability among children worldwide. Linked together by the acronym TORCH, denoting Toxoplasma gondii, rubella virus, cytomegalovirus, and herpes virus, congenital infections can result from only a modest number of human pathogens that cross the placenta and infect the fetus. Although congenital rubella syndrome has been eliminated in the Americas by immunization, several pathogens discussed in this chapter cannot currently be prevented by vaccines or effectively treated with the available antimicrobial drugs. Due to the immaturity of the immune system, newborn infants are at risk for postnatally acquired infections with certain viruses and several bacteria. This chapter summarizes the epidemiology, pathogenesis, clinical manifestations, diagnosis, treatment, and prevention of selected pathogens that can damage the developing nervous system. As emphasized by the persisting challenges of preventing congenital cytomegalovirus infection and the emergence of severe brain damage associated with congenital Zika syndrome, these pathogens remain important causes of cerebral palsy, epilepsy, and intellectual disability.

New-onset ulcerative colitis in pregnancy associated to toxic megacolon and sudden fetal decompensation: Case report and literature review.

Ulcerative colitis (UC) is a chronic inflammatory disease rarely arising during gestation. Because the available information is based on case reports or small retrospective studies, diagnosis may be difficult and treatment is still controversial. A case of toxic megacolon developing in late pregnancy associated to a sudden fetal decompensation is described. Diagnostic and clinical topics of acute UC onset in pregnancy are debated.A primipara, 34 years old, 33/0 weeks of gestation, was admitted with a diagnosis of preterm labor, associated to acute bloody diarrhea (up to 10 daily motions) and cramping abdominal pain. A diagnosis of new-onset early-stage UC was made by sigmoidoscopy. An intensive care regimen including hydrocortisone, antibiotics and parenteral nutrition was immediately started. Magnetic resonance imaging of maternal abdomen, fostered by the worsening patient conditions, evidenced dilatation of the entire colon and a severely hampered of fetal muscular tone.Toxic megacolon complicated by superimposed Clostridium difficile infection was associated to a sudden fetal decompensation diagnosed by chance during maternal abdominal magnetic resonance imaging. An emergency cesarean section was mandatory. According to a senior surgeon's decision, total colectomy was not immediately performed following cesarean section with reference to the absence of colonic perforation. We obtained a good short-term maternal outcome and an uncomplicated neonatal course. Counseling of those patients must be focused on timely and multidisciplinary intervention in order to improve the course of maternal disease and to prevent fetal distress.

Streptococcus pneumoniae - An Uncommon but Noteworthy Cause of Intrauterine Fetal Demise and Acute Necrotizing Funisitis.

Background: Streptococcus pneumoniae (S. pneumoniae) is an uncommon cause of amniotic fluid infection and intrauterine fetal demise. Case report: A 39-year-old G8P2052 presented with preterm premature rupture of membrane at 22 weeks gestation and had a spontaneous vaginal delivery of a neonate who soon expired. Placental examination revealed retroplacental hematoma, acute necrotizing chorioamnionitis, acute three-vessel vasculitis and necrotizing funisitis of the umbilical cord. Postmortem examination demonstrated features of amniotic fluid infection syndrome with blood culture growing S. pneumoniae. Antenatal screening does not typically quantify S. pneumoniae infection, but small series have found vaginal colonization in fewer than 1% of women. Intrauterine or peritoneal infection derives primarily from ascending infection although other routes are hypothetically possible. Intra-amniotic and neonatal infections by S. pneumoniae are associated with high morbidity and mortality. Conclusion: S. pneumoniae should be considered in perinatal death of immature fetus with severe amniotic fluid infection syndrome and acute necrotizing funisitis.

Multidisciplinary evaluation of Clostridium butyricum clonality isolated from preterm neonates with necrotizing enterocolitis in South France between 2009 and 2017.

The association between Clostridium species identification from stool samples in preterm neonates and the occurrence of necrotizing enterocolitis has been increasingly reported. To confirm the specific impact of Clostridium butyricum in this pathology, selective culture procedure was used for Clostridia isolation. Whole-genome analysis was employed to investigate genomic relationships between isolates. Stool samples from present study, as well as from previously investigated cases, were implicated including 88 from preterm neonates with necrotizing enterocolitis and 71 from matched controls. Quantitative real-time polymerase chain reaction was performed to evaluate the presence of C. butyricum from stools of new cases. Clostridium species prevalence isolated by culture was compared between patients with necrotizing enterocolitis and controls. By combining results of both culture and quantitative polymerase chain reaction methods, C. butyricum was significantly more frequent in stool samples from preterm neonates with necrotizing enterocolitis than in controls. Whole-genome analysis of 81 genomes including 58 neonates' isolates revealed that cases were clustered depending on geographical origin of isolation. Controls isolates presented genomic relations with that of patients suggesting a mechanism of asymptomatic carriage. Overall, this suggests an epidemiology comparable to that observed in Clostridium difficile colitis in adults.

Ascending Vaginal Infection Using Bioluminescent Bacteria Evokes Intrauterine Inflammation, Preterm Birth, and Neonatal Brain Injury in Pregnant Mice.

Preterm birth is a serious global health problem and the leading cause of infant death before 5 years of age. At least 40% of cases are associated with infection. The most common way for pathogens to access the uterine cavity is by ascending from the vagina. Bioluminescent pathogens have revolutionized the understanding of infectious diseases. We hypothesized that bioluminescent Escherichia coli can be used to track and monitor ascending vaginal infections. Two bioluminescent strains were studied: E. coli K12 MG1655-lux, a nonpathogenic laboratory strain, and E. coli K1 A192PP-lux2, a pathogenic strain capable of causing neonatal meningitis and sepsis in neonatal rats. On embryonic day 16, mice received intravaginal E. coli K12, E. coli K1, or phosphate-buffered saline followed by whole-body bioluminescent imaging. In both cases, intravaginal delivery of E. coli K12 or E. coli K1 led to bacterial ascension into the uterine cavity, but only E. coli K1 induced preterm parturition. Intravaginal administration of E. coli K1 significantly reduced the proportion of pups born alive compared with E. coli K12 and phosphate-buffered saline controls. However, in both groups of viable pups born after bacterial inoculation, there was evidence of comparable brain inflammation by postnatal day 6. This study ascribes specific mechanisms by which exposure to intrauterine bacteria leads to premature delivery and neurologic inflammation in neonates.

Relationships Between Perinatal Interventions, Maternal-Infant Microbiomes, and Neonatal Outcomes.

The human microbiome acquires its vastness and diversity over a relatively short time period during development. Much is unknown, however, about the precise prenatal versus postnatal timing or its sources and determinants. Given early evidence of a role for influences during pregnancy and early neonatal and infant life on the microbiome and subsequent metabolic health, research investigating the development and shaping of the microbiome in the fetus and neonate is an important arena for study. This article reviews the relevant available literature and future questions on what shapes the microbiome during early development and mechanisms for doing so.

Blackleg in cattle: A case report of fetal infection and a literature review.

Clostridium chauvoei causes blackleg in cattle. The disease has been reported worldwide, and although it can be prevented by vaccination, sporadic cases and occasional outbreaks still occur. We describe a case of blackleg in a 2-y-old, pregnant Gyr cow with in utero transmission to the fetus. The cow had characteristic gross and microscopic lesions of blackleg including widespread necrohemorrhagic and emphysematous skeletal and myocardial myositis, and fibrinous pericarditis. Her uterus contained a near-term, markedly emphysematous fetus with skeletal muscle and myocardial lesions similar to those seen in the dam. Histopathology of dam and fetal tissues revealed numerous gram-positive bacilli, many of them with sub-terminal spores, in multiple tissues. These bacilli were identified as C. chauvoei by immunohistochemistry. Anaerobic culture and fluorescent antibody tests performed on skeletal muscle from both the dam and fetus were positive for C. chauvoei, confirming a diagnosis of blackleg. Blackleg is a so-called endogenous infection, and the currently accepted pathogenesis involves ingestion of spores that are transported to muscle tissues where they lie dormant until anaerobiosis prompts germination. Germinating bacteria are histotoxic, producing severe, local necrosis and ultimately lethal toxemia. This model, however, has not been confirmed experimentally and also fails to explain some cases of the disease. A presumptive diagnosis of blackleg is based on clinical, gross, and histologic findings. Diagnostic confirmation necessitates the detection of C. chauvoei by culture, PCR, or immunodetection methods.

Parvovirus B19 infection during pregnancy and risks to the fetus.

Parvovirus B19 infects 1 to 5% of pregnant women, generally with normal pregnancy outcomes. During epidemics, the rate of infection is higher. Major congenital anomalies among offspring of infected mothers are rare, as the virus does not appear to be a significant teratogen. However, parvovirus B19 infection may cause significant fetal damage, and in rare cases, brain anomalies and neurodevelopmental insults, especially if infection occurs in the first 20 weeks of pregnancy. Parvovirus B19 is also an important cause of fetal loss, especially in the second half of pregnancy when spontaneous fetal loss from other causes is relatively rare. Parvovirus B19 infection may affect many fetal organs and can cause severe anemia, following fetal erythroid progenitor cells infection and apoptosis, especially in fetuses, that have shortened half-life of erythrocytes. Severe anemia may cause high output cardiac failure and nonimmune hydrops fetalis. In addition, parvovirus B19 may directly infect myocardial cells and produce myocarditis that further aggravates the cardiac failure. Intrauterine fetal transfusion is commonly used for the treatment of severe fetal anemia with survival rates of 75 to 90% and significant reduction of fetal morbidity. Only 66 cases were evaluated neurodevelopmentally, of which 10 (16%) had slight or severe neurodevelopmental problems. Because parvovirus B19 infection can cause severe fetal morbidity and mortality, it should be part of the routine work-up of pregnant women who have been exposed to the virus or of pregnancies with suspected fetal hydrops. Assessment for maternal infection during pregnancy is especially important during epidemics, when sero-conversion rates are high. Birth Defects Research 109:311-323, 2017. © 2017 Wiley Periodicals, Inc.

Impact of gestational nicotine exposure on intrauterine and fetal infection in a rodent model.

We investigated the interaction between prenatal nicotine exposure and intrauterine infection using established rat models. Beginning at gestation day (GD) 6, dams were continuously infused with either saline or 6 mg/kg/day nicotine (Nic). At GD 14, dams received either sterile broth or 105 colony-forming units Mycoplasma pulmonis (MP), resulting in four treatment groups: control (4 dams, 33 fetal units); MP only (5 dams, 55 fetal units); Nic only (5 dams, 61 fetal units), and Nic + MP (7 dams, 82 fetal units). At GD 18, nicotine exposure significantly increased (P ≤ 0.02) the percentage of amniotic fluids and fetuses infected by MP but did not impact colonization rates of maternal sites. Nicotine exposure significantly reduced the numbers of MP in the placenta required for high microbial loads (≥104 color-changing units) in the amniotic fluid (P < 0.01). Fetal inflammatory response lesions were most extensive in the Nic only and Nic + MP groups (P < 0.0001). Control and MP only placentas were interleukin (IL)10-dominant, consistent with an M2/Th2 environment. Placentas exposed to nicotine shifted to a neutral environment, with equivalent levels of interferon gamma (IFNG) and IL10. Both IL6 and tumor necrosis factor (TNF) levels in amniotic fluid were highly elevated when both nicotine and infection were present. Our study suggests that prenatal exposure to nicotine increases the risk for intrauterine infection, lowers the infectious dose required to breach the placental barrier and infect the amniotic fluid and fetus, and alters the pathology and inflammatory profile associated with maternal and fetal sites.

Botulism During Pregnancy and the Postpartum Period: A Systematic Review.

Background: Maternal and fetal outcomes associated with botulism and botulinum antitoxin use during pregnancy and the postpartum period have not been systematically reviewed. Methods: We searched Global Health, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Scopus, and Medline databases from inception to May 2015 for studies published on botulism or botulinum antitoxin use during pregnancy and the postpartum period, as well as the Centers for Disease Control and Prevention National Botulism Surveillance database. Our search identified 4517 citations. Results: Sixteen cases of botulism during pregnancy (11 in the third trimester) and 1 case during the postpartum period were identified. Ten cases were associated with confirmed or likely foodborne exposure; 2 cases were attributed to wound contamination related to heroin use, and the source of 5 cases was unknown. Eleven women with botulism had progressive neurologic deterioration and respiratory failure, requiring intensive care unit admission. Four women had adverse outcomes, including 2 deaths and 2 women who remained in a persistent vegetative state. No neonatal losses or cases of congenital botulism were reported. Among the 12 cases that reported neonatal data, 6 neonates were born preterm. No adverse maternal or neonatal events were identified as associated with botulinum antitoxin therapy among 11 patients who received it. Conclusions: Our review of 17 cases of botulism in pregnant/postpartum women found that more than half required ventilator support, 2 women died, and 6 infants were born prematurely. A high level of clinical suspicion is key for early diagnosis and treatment of botulism. Care of pregnant women or new mothers with botulism can include preparation for possible intubation.