Parachlamydia and rhabdochlamydia in premature neonates.
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ABSTRACT:
SUBMITTER: Lamoth F
PROVIDER: S-EPMC3044521 | biostudies-literature | 2009 Dec
REPOSITORIES: biostudies-literature
Publications
Parachlamydia and rhabdochlamydia in premature neonates.
Lamoth Frédéric F Aeby Sébastien S Schneider Antoine A Jaton-Ogay Katia K Vaudaux Bernard B Greub Gilbert G
Emerging infectious diseases 20091201 12
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Project description:Identifying single nucleotide polymorphisms (SNPs) in the genes involved in sepsis may help to clarify the pathophysiology of neonatal sepsis. The aim of this study was to evaluate the relationships between sepsis in pre-term neonates and genes potentially involved in the response to invasion by infectious agents. The study involved 101 pre-term neonates born between June 2008 and May 2012 with a diagnosis of microbiologically confirmed sepsis, 98 pre-term neonates with clinical sepsis and 100 randomly selected, otherwise healthy pre-term neonates born during the study period. During the study, 47 SNPs in 18 candidate genes were genotyped on Guthrie cards using an ABI PRISM 7900 HT Fast real-time and MAssARRAY for nucleic acids instruments. Genotypes CT and TT of rs1143643 (the IL1β gene) and genotype GG of rs2664349GG (the MMP-16 gene) were associated with a significantly increased overall risk of developing sepsis (p = 0.03, p = 0.05 and p = 0.03), whereas genotypes AG of rs4358188 (the BPI gene) and CT of rs1799946 (the DEFβ1 gene) were associated with a significantly reduced risk of developing sepsis (p = 0.05 for both). Among the patients with bacteriologically confirmed sepsis, only genotype GG of rs2664349 (the MMP-16 gene) showed a significant association with an increased risk (p = 0.02). Genotypes GG of rs2569190 (the CD14 gene) and AT of rs4073 (the IL8 gene) were associated with a significantly increased risk of developing severe sepsis (p = 0.05 and p = 0.01). Genotype AG of rs1800629 (the LTA gene) and genotypes CC and CT of rs1341023 (the BPI gene) were associated with a significantly increased risk of developing Gram-negative sepsis (p = 0.04, p = 0.04 and p = 0.03). These results show that genetic variability seems to play a role in sepsis in pre-term neonates by influencing susceptibility to and the severity of the disease, as well as the risk of having disease due to specific pathogens.
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Project description:BackgroundNeonatal sepsis due to intestinal bacterial translocation is a major cause of morbidity and mortality. Understanding microbial colonisation of the gut in prematurity may predict risk of sepsis to guide future strategies to manipulate the microbiome.MethodsProspective longitudinal study of premature infants. Stool samples were obtained weekly. DNA was extracted and the V6 hypervariable region of 16S rRNA was amplified followed by high throughput pyrosequencing, comparing subjects with and without sepsis.ResultsSix neonates were 24-27 weeks gestation at birth and had 18 samples analysed. Two subjects had no sepsis during the study period, two developed late-onset culture-positive sepsis and two had culture-negative systemic inflammation. 324 350 sequences were obtained. The meconium was not sterile and had predominance of Lactobacillus, Staphylococcus and Enterobacteriales. Overall, infants who developed sepsis began life with low microbial diversity, and acquired a predominance of Staphylococcus, while healthy infants had more diversity and predominance of Clostridium, Klebsiella and Veillonella.ConclusionsIn very low birth weight infants, the authors found that meconium is not sterile and is less diverse from birth in infants who will develop late-onset sepsis. Empiric, prolonged antibiotics profoundly decrease microbial diversity and promote a microbiota that is associated not only with neonatal sepsis, but the predominant pathogen previously identified in the microbiome. Our data suggest that there may be a 'healthy microbiome' present in extremely premature neonates that may ameliorate risk of sepsis. More research is needed to determine whether altered antibiotics, probiotics or other novel therapies can re-establish a healthy microbiome in neonates.
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Project description:ObjectivesDetermine if chronologic age and/or chorioamnionitis exposure alter normal serum cytokine and chemokine levels in uninfected preterm neonates during their initial NICU stay.Study designA 7-plex immunoassay measured levels of serum IL-1β, IL-6, IL-8, IL-10, TNF-α, CCL2, and CCL3 longitudinally from chorioamnionitis-exposed and unexposed preterm neonates under 33 weeks' gestation.ResultsChorioamnionitis-exposed and unexposed preterm neonates demonstrated differences in the trends of IL-1β, IL-6, IL-8, IL-10, TNF-α, and CCL2 over the first month of life. The unexposed neonates demonstrated elevated levels of these inflammatory markers in the first two weeks of life with a decrease by the third week of life, while the chorioamnionitis-exposed neonates demonstrated differences over time without a predictable pattern. Chorioamnionitis-exposed and unexposed neonates demonstrated altered IL-10 and TNF-α trajectories over the first twelve weeks of life.ConclusionChorioamnionitis induces a state of immune dysregulation in preterm neonates that persists beyond the immediate neonatal period.
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Project description:Early prediction of bronchopulmonary dysplasia (BPD) may facilitate tailored management for neonates at risk. We investigated whether easily accessible flow data from a mechanical ventilator can predict BPD in neonates born extremely premature (EP). In a prospective population-based study of EP-born neonates, flow data were obtained from the ventilator during the first 48 h of life. Data were logged for >10 min and then converted to flow-volume loops using custom-made software. Tidal breathing parameters were calculated and averaged from ≥200 breath cycles, and data were compared between those who later developed moderate/severe and no/mild BPD. Of 33 neonates, 18 developed moderate/severe and 15 no/mild BPD. The groups did not differ in gestational age, surfactant treatment or ventilator settings. The infants who developed moderate/severe BPD had evidence of less airflow obstruction, significantly so for tidal expiratory flow at 50% of tidal expiratory volume (TEF50) expressed as a ratio of peak tidal expiratory flow (PTEF) (p=0.007). A compound model estimated by multiple logistic regression incorporating TEF50/PTEF, birthweight z-score and sex predicted moderate/severe BPD with good accuracy (area under the curve 0.893, 95% CI 0.735-0.973). This study suggests that flow data obtained from ventilators during the first hours of life may predict later BPD in premature neonates. Future and larger studies are needed to validate these findings and to determine their clinical usefulness.
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Project description:Background and purposeAbnormal cerebral microstructure has been documented in term neonates with congenital heart disease, portending risk for injury and poor neurodevelopmental outcome. Our hypothesis was that preterm neonates with congenital heart disease would demonstrate diffuse cerebral microstructural abnormalities when compared with critically ill neonates without congenital heart disease. A secondary aim was to identify any association between microstructural abnormalities, white matter injury (eg, punctate white matter lesions), and other clinical variables, including heart lesions.Materials and methodsWith the use of tract-based spatial statistics, an unbiased, voxelwise method for analyzing diffusion tensor imaging data, we compared 21 preterm neonates with congenital heart disease with 2 cohorts of neonates without congenital heart disease: 28 term and 27 preterm neonates, identified from the same neonatal intensive care unit.ResultsCompared with term neonates without congenital heart disease, preterm neonates with congenital heart disease had microstructural abnormalities in widespread regions of the central white matter. However, 42% of the preterm neonates with congenital heart disease had punctate white matter lesions. When neonates with punctate white matter lesions were excluded, microstructural abnormalities remained only in the splenium. Preterm neonates with congenital heart disease had similar microstructure to preterm neonates without congenital heart disease.ConclusionsDiffuse microstructural abnormalities were observed in preterm neonates with congenital heart disease, strongly associated with punctate white matter lesions. Independently, regional vulnerability of the splenium, a structure associated with visual spatial function, was observed in all preterm neonates with congenital heart disease.
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Project description:BackgroundAntimicrobial responses have been shown to be profoundly attenuated in very preterm neonates when examined on cord blood. However, we lack data on these responses at the time these neonates are most vulnerable to infections.MethodsMultiple cytokine responses to two prototypic Toll-like receptor (TLR) agonists: lipopolysaccharide (LPS) (TLR4) and R848 (TLR7/8) were prospectively measured in preterm neonates born ≤30 wk of gestation (n = 50) during the first 28 d of age using whole blood and single-cell multiparameter flow cytometry assays. Results were compared to term neonates (n = 30) and adult controls (n = 25).ResultsIn preterm neonates, LPS and R848 responses remained attenuated in both cord blood and in the first 28 d of age. These responses showed significant maturation over time after adjusting for gestational age and were confirmed in monocytes and dendritic cells on a per-cell basis. We detected no major contribution of chorioamnionitis, maternal antenatal corticosteroids or magnesium sulfate treatment, labor, or mode of delivery to the maturation of cytokine responses.ConclusionInnate immune antimicrobial defenses are profoundly attenuated developmentally in very preterm neonates during the neonatal period, suggesting that exogenous factors drive the sustained systemic inflammation that has been linked to increased morbidities in these infants.
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Project description:Bacterial sepsis is a major threat in neonates born prematurely, and is associated with elevated morbidity and mortality. Little is known on the innate immune response to bacteria among extremely premature infants.We compared innate immune functions to bacteria commonly causing sepsis in 21 infants of less than 28 wks of gestational age, 24 infants born between 28 and 32 wks of gestational age, 25 term newborns and 20 healthy adults. Levels of surface expression of innate immune receptors (CD14, TLR2, TLR4, and MD-2) for Gram-positive and Gram-negative bacteria were measured in cord blood leukocytes at the time of birth. The cytokine response to bacteria of those leukocytes as well as plasma-dependent opsonophagocytosis of bacteria by target leukocytes was also measured in the presence or absence of interferon-?. Leukocytes from extremely premature infants expressed very low levels of receptors important for bacterial recognition. Leukocyte inflammatory responses to bacteria and opsonophagocytic activity of plasma from premature infants were also severely impaired compared to term newborns or adults. These innate immune defects could be corrected when blood from premature infants was incubated ex vivo 12 hrs with interferon-?.Premature infants display markedly impaired innate immune functions, which likely account for their propensity to develop bacterial sepsis during the neonatal period. The fetal innate immune response progressively matures in the last three months in utero. Ex vivo treatment of leukocytes from premature neonates with interferon-? reversed their innate immune responses deficiency to bacteria. These data represent a promising proof-of-concept to treat premature newborns at the time of delivery with pharmacological agents aimed at maturing innate immune responses in order to prevent neonatal sepsis.
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