Histological chorioamnionitis – implication for bacterial colonization, laboratory markers of infection, and early onset sepsis in very-low-birth-weight neonates

Association of clinical signs of chorioamnionitis with histological chorioamnionitis and neonatal outcomes

BACKGROUND

Chorioamnionitis is a risk factor for fetal and neonatal outcomes. Therefore, predicting histological chorioamnionitis (HCA) and neonatal outcomes using clinical parameters could be helpful in management and preventing morbidities.

OBJECTIVE

To determine if parameters of clinical chorioamnionitis (CCA) would be associated with HCA and neonatal outcomes.

STUDY DESIGN

In this cohort study using a retrospective design, we analyzed the performance of signs of CCA in predicting HCA, and neonatal outcomes. Data were extracted from the electronic health record for all neonates with documented CCA delivered at our institution from 2011 to 2016. We compared our findings based on the old ACOG definition of CCA and the new definition released in 2017 - maternal fever plus any of fetal tachycardia, maternal leukocytosis, and purulent vaginal discharge. Maternal tachycardia and uterine tenderness were removed from the new criteria. Neonatal laboratory samples on admission, 12 h and 24 h were used to define the three time points of neonatal suspected sepsis.

RESULTS

There were 530 mothers-infant dyads with chorioamnionitis. Seventy-three were preterm, and 457 were term. Eighty-eight percent of the preterm mothers had CCA, and HCA was present in 62.5% of 72 preterm placentas. Preterm infants with placental HCA significantly had lower birth weight, gestational age, placental weight, and more infants with lower 5-minute Apgar scores, compared to those with no HCA. In preterm infants, maternal urinary tract infection was significantly associated with decreased odds for HCA (OR 0.22, CI 0.10 - 0.71). More preterm babies with suspected sepsis criteria at the 3 time points had HCA (all p ≤ .01). In the term cohort, 95.4% and 65.6% had CCA and HCA, respectively. In term infants (n = 457), maternal leukocytosis (p = .002) and prolonged rupture of membranes (PROM; p = 002) were associated with HCA. Suspected sepsis was associated with PROM (p = .04), HCA (p = .0001), and maternal leukocytosis (p ≤ .05) in at least 1 of the 3 time points.

CONCLUSION

Though maternal leukocytosis was significantly associated with the presence of HCA in the term cohort, there were no CCA criteria that accurately predicted presence of HCA in either the preterm or the term infants.

Association of Histological and Clinical Chorioamnionitis With Neonatal Sepsis Among Preterm Infants: A Systematic Review, Meta-Analysis, and Meta-Regression

Chorioamnionitis (CA) is considered a key risk factor for very preterm birth and for developing early onset sepsis (EOS) in preterm infants, but recent data suggest that CA might be protective against late onset sepsis (LOS). We performed a systematic review and meta-analysis of studies exploring the association between CA and sepsis. A comprehensive literature search was performed in PubMed/MEDLINE and EMBASE, from their inception to December 1, 2018. A random-effects model was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Sources of heterogeneity were analyzed by subgroup and meta-regression analyses. The following categories of sepsis were analyzed: EOS, LOS, unspecified onset sepsis (UOS), culture-proven, and clinical sepsis. CA was subdivided into clinical and histological chorioamnionitis. Funisitis was also analyzed. We found 3,768 potentially relevant studies, of which 107 met the inclusion criteria (387,321 infants; 44,414 cases of CA). Meta-analysis showed an association between any CA and any EOS (OR 4.29, CI 3.63-5.06), any LOS (OR 1.29, CI 1.11-1.54), and any UOS (OR 1.59, CI 1.11-1.54). Subgroup analysis showed that CA was associated with culture-proven EOS (OR 4.69, CI 3.91-5.56), clinical EOS (OR 3.58, CI 1.90-6.76), and culture-proven LOS (OR 1.31, CI 1.12-1.53), but not with clinical LOS (OR 1.52, CI 0.78-2.96). The presence of funisitis did not increase the risk of either EOS or LOS when compared with CA without funisitis. CA-exposed infants had lower gestational age (-1.11 weeks, CI -1.37 to -0.84) than the infants not exposed to CA. Meta-regression analysis showed that the lower gestational age of the CA group correlated with the association between CA and LOS but not with the association between CA and EOS. In conclusion, our data suggest that the positive association between chorioamnionitis and LOS may be modulated by the effect of chorioamnionitis on gestational age.

Impact of different stages of intrauterine inflammation on outcome of preterm neonates: Gestational age-dependent and -independent effect

Objective

To investigate the impact of different stages of intrauterine inflammation (IUI) on neonatal outcomes, before and after adjusting for gestational age (GA) and other perinatal confounders.

Methods

This was an observational, prospective, single-center cohort study including all eligible neonates with GA < 35 weeks and/or birth weight ≤ 1500 g born at a 3^rd level Neonatal Intensive Care Unit between 2011 and 2014. Pathological patterns of placenta, membranes and cord were classified according to Redline’s criteria. Multivariable linear and logistic regression models were applied, either including or not GA among the covariates.

Results

Of the 807 enrolled neonates, 134 (16.6%) had signs of IUI: among these, 54.5% showed just histological chorioamnionitis (HCA), 25.4% had HCA + funisitis (FUN) stage 1, and 20.1% had HCA + FUN stage 2–3. At univariate analysis, HCA increased the risk for retinopathy of prematurity (ROP) and bronchopulmonary dysplasia, while FUN (any stage) had a deleterious impact on all outcomes investigated. After adjustment for covariates not including GA, HCA was a risk factor only for ROP (OR = 2.8, CI: 1–7.8), while FUN (any stage) was still associated with increased ORs for all outcomes (p <0.01). Upon inclusion of GA in the regression model, the results differed remarkably. HCA was associated with lower risk for mechanical ventilation (OR = 0.3, CI: 0.1–0.7) and need for surfactant (OR = 0.5, CI: 0.2–0.9), while FUN (any stage) worsened clinical conditions at birth (p <0.05), increased the risk for early-onset sepsis (p <0.01), and increased the length of mechanical ventilation (FUN stage 2–3 only, RC = 6.5 days, CI: 2–11). No other outcome was affected.

Conclusions

IUI, especially FUN, negatively impact most neonatal morbidities, but its effect is partially reverted adjusting for GA. Considered that GA is an intermediate variable interposed between prenatal causes of prematurity and outcomes, the appropriateness of adjusting for GA may be questionable.

Pilot study demonstrates that placental histology can provide an additional tool for diagnosing early-onset neonatal sepsis

AIM

We explored whether placental histology could help to diagnose early-onset neonatal sepsis (EONS), guide clinical decision-making 48 hours after birth and reduce antibiotic use.

METHODS

This study comprised 109 infants born at less than 32 weeks of gestation, who were admitted to the neonatal intensive care unit of Isala, Zwolle, The Netherlands, between January 2013 and December 2013. EONS was defined as clinical symptoms plus raised serial C-reactive protein (CRP) >10 mg/L and a positive (proven EONS) or a negative (suspected EONS) blood culture. Placentas were studied for a histological inflammatory response and scored according to Redline's criteria.

RESULTS

A histological inflammatory response was seen in 15/88 (17%) placentas and this occurred significantly more often in infants with a high suspicion of EONS (p < 0.05). No histological inflammatory response was seen if maternal risk factors for EONS were absent, despite a raised CRP level. Based on placental histology, the duration of antibiotic therapy was reduced from more than five days to 48 hours in 20/27 infants (74%).

CONCLUSION

Histological examination of the placenta helped to diagnose EONS and guide clinical decision-making 48 hours after birth and led to a clinically relevant reduction in antibiotic use.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.

Golden hour of neonatal life: Need of the hour

"Golden Hour" of neonatal life is defined as the first hour of post-natal life in both preterm and term neonates. This concept in neonatology has been adopted from adult trauma where the initial first hour of trauma management is considered as golden hour. The "Golden hour" concept includes practicing all the evidence based intervention for term and preterm neonates, in the initial sixty minutes of postnatal life for better long-term outcome. Although the current evidence supports the concept of golden hour in preterm and still there is no evidence seeking the benefit of golden hour approach in term neonates, but neonatologist around the globe feel the importance of golden hour concept equally in both preterm and term neonates. Initial first hour of neonatal life includes neonatal resuscitation, post-resuscitation care, transportation of sick newborn to neonatal intensive care unit, respiratory and cardiovascular support and initial course in nursery. The studies that evaluated the concept of golden hour in preterm neonates showed marked reduction in hypothermia, hypoglycemia, intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP). In this review article, we will discuss various components of neonatal care that are included in "Golden hour" of preterm and term neonatal care.

Cord Blood Acute Phase Reactants Predict Early Onset Neonatal Sepsis in Preterm Infants

BACKGROUND

Early onset sepsis (EOS) is a major cause of morbidity and mortality in preterm infants, yet diagnosis remains inadequate resulting in missed cases or prolonged empiric antibiotics with adverse consequences. Evaluation of acute phase reactant (APR) biomarkers in umbilical cord blood at birth may improve EOS detection in preterm infants with intrauterine infection.

METHODS

In this nested case-control study, infants (29.7 weeks gestation, IQR: 27.7-32.2) were identified from a longitudinal cohort with archived cord blood and placental histopathology. Patients were categorized using culture, laboratory, clinical, and antibiotic treatment data into sepsis groups: confirmed sepsis (cEOS, n = 12); presumed sepsis (PS, n = 30); and no sepsis (controls, n = 30). Nine APRs were measured in duplicate from cord blood using commercially available multiplex immunoassays (Bio-Plex Pro™). In addition, placental histopathologic data were linked to biomarker results.

RESULTS

cEOS organisms were Escherichia coli, Streptococcus agalactiae, Proteus mirabilis, Haemophilus influenzae and Listeria monocytogenes. C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp), serum amyloid P and ferritin were significantly elevated in cEOS compared to controls (p<0.01). SAA, CRP, and Hp were elevated in cEOS but not in PS (p<0.01) and had AUCs of 99%, 96%, and 95% respectively in predicting cEOS. Regression analysis revealed robust associations of SAA, CRP, and Hp with EOS after adjustment for covariates. Procalcitonin, fibrinogen, α-2-macroglobulin and tissue plasminogen activator were not significantly different across groups. Placental acute inflammation was associated with APR elevation and was present in all cEOS, 9 PS, and 17 control infants.

CONCLUSION

This study shows that certain APRs are elevated in cord blood of premature infants with EOS of intrauterine origin. SAA, CRP, and Hp at birth have potential diagnostic utility for risk stratification and identification of infants with EOS.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Gastric fluid versus amniotic fluid analysis for the identification of intra-amniotic infection due to Ureaplasma species

OBJECTIVE

Early neonatal sepsis is often due to intra-amniotic infection. The stomach of the neonate contains fluid swallowed before and during delivery. The presence of bacteria as well as neutrophils detected by culture or Gram stain of the gastric fluid during the first day of life is suggestive of exposure to bacteria or inflammation. We undertook this study to determine the relationship between gastric fluid analysis and amniotic fluid obtained by transabdominal amniocentesis in the detection of Ureaplasma species, the most frequent microorganisms responsible for intra-amniotic infection.

MATERIALS AND METHODS

The study population consisted of 100 singleton pregnant women who delivered preterm neonates (<35 weeks) within 7 days of amniocentesis. Gastric fluid of newborns was obtained by nasogastric intubation on the day of birth. Amniotic fluid and gastric fluid were cultured for genital Mycoplasmas, and polymerase chain reaction (PCR) for Ureaplasma species was performed. Intra-amniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration (>23 ng/mL).

RESULTS

(1) Ureaplasma species were detected by culture or PCR in 18% (18/100) of amniotic fluid samples and in 5% (5/100) of gastric fluid samples; (2) among the amniotic fluid cases positive for Ureaplasma species, these microorganisms were identified in 27.8% (5/18) of gastric fluid samples; (3) none of the cases negative for Ureaplasma species in the amniotic fluid were found to be positive for these microorganisms in the gastric fluid; (4) patients with amniotic fluid positive for Ureaplasma species but with gastric fluid negative for these microorganisms had a significantly higher rate of intra-amniotic inflammation, acute histologic chorioamnionitis, and neonatal death than those with both amniotic fluid and gastric fluid negative for Ureaplasma species; and (5) no significant differences were observed in the rate of intra-amniotic inflammation, acute histologic chorioamnionitis, and neonatal death between patients with amniotic fluid positive for Ureaplasma species but with gastric fluid negative for these microorganisms and those with both amniotic fluid and gastric fluid positive for Ureaplasma species.

CONCLUSIONS

Gastric fluid analysis has 100% specificity in the identification of intra-amniotic infection with Ureaplasma species. However, the detection of Ureaplasma species by culture or PCR in the gastric fluid of neonates at birth did not identify these microorganisms in two-thirds of cases with microbial invasion of the amniotic cavity. Thus, amniotic fluid analysis is superior to that of gastric fluid in the identification of intra-amniotic infection.

A toll-like receptor 9 (rs352140) variant is associated with placental inflammation in newborn infants

OBJECTIVE

Chorioamnionitis contributes to premature birth and associated postnatal morbidity. The genetic basis of altered immune responses underlying placental inflammation (PI) remains understudied. The aim of this study was to evaluate the relationship among TLR signaling pathway polymorphisms and different patterns of PI.

METHODS

Prospective cohort study in infants involving cord blood collection and placental examination for PI. One hundred and fifty-nine infants enrolled in study out of which 28 were term (eight with PI) and 131 preterm (47 with PI). DNA from blood was genotyped for SNPs in TLR2, 4, 5, 9, NFKBI, NFKBIA, TIRAP, and IRAK1 genes using multiplexed single base extension assay.

RESULTS

While there were no differences in BW, GA, gender, race, and SPL among infants with or without PI, there was a higher incidence of PPROM, maternal smoking, drug use, and clinical chorioamnionitis among infants with PI. Out of nine TLR variants, only CT and/or TT genotypes of the TLR9 variant (rs352140) were significantly associated (p = 0.004) with any PI and maternal pattern of inflammation (p = 0.012) both by univariate analysis and logistic regression.

CONCLUSIONS

The presence of a variant T allele in a common SNP (rs352140) in the TLR9 gene whose product recognizes bacterial DNA is associated with increased PI.

Chorioamnionitis: implications for the neonate

Chorioamnionitis (CA) is characterized by inflammation of the fetal membranes. The incidence increases with decreasing gestational age at birth. When suspected on clinical criteria, pathologic assessment of the placenta should be performed. Although the mechanisms are not entirely clear, CA predisposes to premature birth, neonatal sepsis, and intraventricular hemorrhage. Its role in respiratory distress syndrome, bronchopulmonary dysplasia, and neurodevelopmental impairment is mixed. Prevention and treatment are ill-defined; antibiotics for preterm premature rupture of membranes reduce the incidence and increase the length of time to delivery. Antibiotics are recommended for infants exposed to CA while laboratory studies are being performed.

The clinical implications of placental diagnoses

The clinical utility of placental pathology is both overestimated and underestimated, and the overall quality of placental pathology reporting, even at major medical centers, is highly variable. Clear benefits of examining placentas include the immediate diagnosis of treatable conditions in both the mother and the infant, clarification of the underlying etiology of adverse pregnancy outcomes, estimation of recurrence risk, and guidance for the management of future pregnancies. In order to realize these benefits and get the most out of their pathology departments, it is critical for clinicians to understand the range and implications of placental lesions. This article will review the nomenclature, diagnostic criteria and pitfalls, and clinical significance of seven common placental disease processes and a handful of other lesions.

Risk of early-onset neonatal infection with maternal infection or colonization: a global systematic review and meta-analysis

BACKGROUND

Neonatal infections cause a significant proportion of deaths in the first week of life, yet little is known about risk factors and pathways of transmission for early-onset neonatal sepsis globally. We aimed to estimate the risk of neonatal infection (excluding sexually transmitted diseases [STDs] or congenital infections) in the first seven days of life among newborns of mothers with bacterial infection or colonization during the intrapartum period.

METHODS AND FINDINGS

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, and the World Health Organization Regional Databases for studies of maternal infection, vertical transmission, and neonatal infection published from January 1, 1960 to March 30, 2013. Studies were included that reported effect measures on the risk of neonatal infection among newborns exposed to maternal infection. Random effects meta-analyses were used to pool data and calculate the odds ratio estimates of risk of infection. Eighty-three studies met the inclusion criteria. Seven studies (8.4%) were from high neonatal mortality settings. Considerable heterogeneity existed between studies given the various definitions of laboratory-confirmed and clinical signs of infection, as well as for colonization and risk factors. The odds ratio for neonatal lab-confirmed infection among newborns of mothers with lab-confirmed infection was 6.6 (95% CI 3.9-11.2). Newborns of mothers with colonization had a 9.4 (95% CI 3.1-28.5) times higher odds of lab-confirmed infection than newborns of non-colonized mothers. Newborns of mothers with risk factors for infection (defined as prelabour rupture of membranes [PROM], preterm <37 weeks PROM, and prolonged ROM) had a 2.3 (95% CI 1.0-5.4) times higher odds of infection than newborns of mothers without risk factors.

CONCLUSIONS

Neonatal infection in the first week of life is associated with maternal infection and colonization. High-quality studies, particularly from settings with high neonatal mortality, are needed to determine whether targeting treatment of maternal infections or colonization, and/or prophylactic antibiotic treatment of newborns of high risk mothers, may prevent a significant proportion of early-onset neonatal sepsis. Please see later in the article for the Editors' Summary.

Relationship between the neonatal white blood cell count and histologic chorioamnionitis in preterm newborns

OBJECTIVE

The aim was to examine the relationship between neonatal white blood cell (WBC) count and the diagnosis of histologic chorioamnionitis (HCA).

DESIGN

We measured WBC, a widely used marker of inflammation, to evaluate whether the values at birth were associated with HCA.

SETTING

NICU, Department of Pediatrics of Padua University, Padua, Italy.

SUBJECTS

WBC count was evaluated in 71 preterm neonates (<32 weeks of gestation) with HCA and in a control group without HCA on day 1, 3, and 6 after delivery. Logistic regression analysis and diagnostic accuracy analysis were used to assess the association between WBC counts and HCA.

MAIN RESULTS

WBC levels were significantly higher in infants with HCA than in those without HCA (Median IQR, WBC (x10(9)/l): day 1, 13.2 (6.2-21.8) vs 8.1 (6-11.4), p < 0.001; day 3, 17.4 (11.4-26.9) vs 6.3 (5.2-8.3), p < 0.001; day 6, 18.4 (11.1-31) vs 6.5 (4.4-9), p < 0.0001). The neonatal WBC count on the third day of life was the most sensitive parameter associated with HCA (sensitivity: 0.80; specificity: 0.88). The cut-off value based on the ROC curve was 10 (x10(9)/l).

CONCLUSIONS

WBC count in the third day of life is strongly associated with HCA.