Effects of pasteurization on osteopontin concentrations in human breastmilk.

BACKGROUND: Osteopontin (OPN) is an important breastmilk protein involved in infant intestinal, immunological, and brain development. However, little is known about how common milk pasteurization and storage techniques affect this important bioactive protein. METHODS: Human milk osteopontin concentration was measured in single-donor fresh (n = 1) or frozen (n = 20) breastmilk, pooled Holder-pasteurized donor breastmilk (n = 11), and a shelf-stable (retort pasteurized) breastmilk product (n = 2) by ELISA. Single-donor breastmilk samples were subjected to pasteurization and/or freezing before measuring osteopontin concentrations. RESULTS: Holder pasteurization of breastmilk resulted in an ∼50% decrease in osteopontin concentration within single-donor samples. Breastmilk from mothers of preterm infants trended toward higher osteopontin concentration than mothers of term infants; however, samples from preterm mothers experienced greater osteopontin degradation upon pasteurization. A commercial breastmilk product that underwent retort pasteurization had lower osteopontin concentration than a Holder-pasteurized pooled breastmilk product. Finally, freezing breastmilk prior to Holder pasteurization resulted in less osteopontin degradation than Holder pasteurization prior to freezing. CONCLUSIONS: Commonly used breastmilk pasteurization and storage techniques, including freezing and Holder pasteurization, decrease the concentration of the bioactive protein osteopontin in human breastmilk. Holder pasteurization reduced osteopontin concentration by an average of 63%, while freezing resulted in an 8-12% decrease. IMPACT: Pasteurization of human breastmilk significantly decreases the concentration of the bioactive protein osteopontin. Use of both pasteurization and freezing techniques for breastmilk preservation results in greater loss of osteopontin. This study presents for the first time an analysis of osteopontin concentrations in single-donor pasteurized milk samples.

Placenta and Intestinal Injury in Preterm Infants.

Necrotizing enterocolitis (NEC) is one of the most common gastrointestinal conditions affecting 6 to 10% of low-birth-weight infants and remains a leading cause of death. The risk factors associated with NEC are complex and multifactorial, including preterm birth and intrauterine exposure to inflammation and hypoxia. Chorioamnionitis has been associated with intestinal injury in animal and human clinical studies. This review presents current evidence about the clinical impact of the intrauterine environment on intestinal injury during pregnancy and postpregnancy. We present information from our own clinical and laboratory research in conjunction with information collected from an extensive search in the databases PubMed, EMBASE, and Scopus. Prospective multicenter studies, including accurate and precise clinical, maternal, and laboratory predictors (e.g., inflammatory biomarkers), will help identify the mechanisms associated with the placental pathology, the development of NEC, and the impact of in utero-triggered inflammation on the clinical outcomes. Filling the knowledge gap to link the inflammatory surge to postnatal life will aid in identifying at-risk infants for NEC in a timely manner and facilitate the development of novel immunomodulatory treatments or interventions to improve the outcomes of these vulnerable infants. KEY POINTS: · Placental inflammatory and vascular lesions are associated with NEC severity.. · Higher grade chorioamnionitis with a fetal response is associated with an increased risk of surgical NEC.. · There is a need for routine bedside utilization of placenta pathology in clinical decision-making..

Effect of Early vs Late Inguinal Hernia Repair on Serious Adverse Event Rates in Preterm Infants: A Randomized Clinical Trial.

Importance: Inguinal hernia repair in preterm infants is common and is associated with considerable morbidity. Whether the inguinal hernia should be repaired prior to or after discharge from the neonatal intensive care unit is controversial. Objective: To evaluate the safety of early vs late surgical repair for preterm infants with an inguinal hernia. Design, Setting, and Participants: A multicenter randomized clinical trial including preterm infants with inguinal hernia diagnosed during initial hospitalization was conducted between September 2013 and April 2021 at 39 US hospitals. Follow-up was completed on January 3, 2023. Interventions: In the early repair strategy, infants underwent inguinal hernia repair before neonatal intensive care unit discharge. In the late repair strategy, hernia repair was planned after discharge from the neonatal intensive care unit and when the infants were older than 55 weeks' postmenstrual age. Main Outcomes and Measures: The primary outcome was occurrence of any prespecified serious adverse event during the 10-month observation period (determined by a blinded adjudication committee). The secondary outcomes included the total number of days in the hospital during the 10-month observation period. Results: Among the 338 randomized infants (172 in the early repair group and 166 in the late repair group), 320 underwent operative repair (86% were male; 2% were Asian, 30% were Black, 16% were Hispanic, 59% were White, and race and ethnicity were unknown in 9% and 4%, respectively; the mean gestational age at birth was 26.6 weeks [SD, 2.8 weeks]; the mean postnatal age at enrollment was 12 weeks [SD, 5 weeks]). Among 308 infants (91%) with complete data (159 in the early repair group and 149 in the late repair group), 44 (28%) in the early repair group vs 27 (18%) in the late repair group had at least 1 serious adverse event (risk difference, -7.9% [95% credible interval, -16.9% to 0%]; 97% bayesian posterior probability of benefit with late repair). The median number of days in the hospital during the 10-month observation period was 19.0 days (IQR, 9.8 to 35.0 days) in the early repair group vs 16.0 days (IQR, 7.0 to 38.0 days) in the late repair group (82% posterior probability of benefit with late repair). In the prespecified subgroup analyses, the probability that late repair reduced the number of infants with at least 1 serious adverse event was higher in infants with a gestational age younger than 28 weeks and in those with bronchopulmonary dysplasia (99% probability of benefit in each subgroup). Conclusions and Relevance: Among preterm infants with inguinal hernia, the late repair strategy resulted in fewer infants having at least 1 serious adverse event. These findings support delaying inguinal hernia repair until after initial discharge from the neonatal intensive care unit. Trial Registration: ClinicalTrials.gov Identifier: NCT01678638.

CD8αα⁺ innate-type lymphocytes in the intestinal epithelium mediate mucosal immunity.

Innate immune responses are critical for mucosal immunity. Here we describe an innate lymphocyte population, iCD8α cells, characterized by expression of CD8α homodimers. iCD8α cells exhibit innate functional characteristics such as the capacity to engulf and kill bacteria. Development of iCD8α cells depends on expression of interleukin-2 receptor γ chain (IL-2Rγc), IL-15, and the major histocompatibility complex (MHC) class Ib protein H2-T3, also known as the thymus leukemia antigen or TL. While lineage tracking experiments indicated that iCD8α cells have a lymphoid origin, their development was independent of the transcriptional suppressor Id2, suggesting that these cells do not belong to the family of innate lymphoid cells. Finally, we identified cells with a similar phenotype in humans, which were profoundly depleted in newborns with necrotizing enterocolitis. These findings suggest a critical role of iCD8α cells in immune responses associated with the intestinal epithelium.

Clinical impact of NEC-associated sepsis on outcomes in preterm infants.

OBJECTIVE: To determine risk factors and outcomes of necrotizing enterocolitis (NEC)-associated sepsis in infants with NEC. METHODS: A retrospective review comparing demographic and clinical information in infants with and without NEC-associated sepsis (defined as positive blood culture at the time of NEC onset). RESULTS: A total of 209 infants with medical (n = 98) and surgical NEC (n = 111) had a median gestational age of 27 weeks (IQR 25; 30.5) and a median birth weight of 910 g [IQR 655; 1138]. Fifty of 209 (23.9%) infants had NEC-associated sepsis. Infants with NEC-associated sepsis had lower median GA (26.4 vs. 27.4 weeks; p = 0.01), lower birth weight (745 vs. 930 g; p = 0.009), were more likely mechanically ventilated [p < 0.001], received dopamine [p < 0.001], had more evidence of acute kidney injury [60% vs. 38.4%, p = 0.01], longer postoperative ileus (16 [13.0; 22.0] vs. 12 [8; 16] days; p = 0.006), higher levels of C-reactive protein, lower platelet counts, longer hospitalization compared to infants without NEC-associated sepsis. On multivariate regression, cholestasis was an independent risk factor for NEC-associated sepsis (OR 2.94; 95% CI 1.1-8.8, p = 0.038). CONCLUSION: NEC-associated sepsis was associated with greater hemodynamic support, acute kidney injury, longer postoperative ileus, and hospitalization on bivariate analysis, and cholestasis was associated with higher odds of sepsis on multi regression analysis. IMPACT: NEC-associated sepsis was present in 24% of infants with NEC. Gram-positive bacteria, Gram-negative bacteria, and Candida were found in 15.3%, 10.5%, and 2.8% of cases, respectively. Infants with NEC-associated sepsis had a greater inflammatory response (CRP levels), received more blood transfusion before NEC onset, frequently needed assisted ventilation ionotropic support, and had acute kidney injury after NEC onset. NEC infants with Gram-negative sepsis had higher portal venous gas, received more platelet transfusions before NEC onset, and had higher CRP levels and lower median lymphocyte counts at 24 h after NEC onset than those with Gram-positive sepsis.

Randomized trial of azithromycin to eradicate Ureaplasma respiratory colonization in preterm infants: 2-year outcomes.

BACKGROUND: To assess the potential impact of azithromycin treatment in the first week following birth on 2-year outcomes in preterm infants with and without Ureaplasma respiratory colonization who participated in a double-blind, placebo-controlled randomized controlled trial. METHODS: Respiratory morbidity was assessed at NICU discharge and at 6, 12, and 22-26 months corrected age using pulmonary questionnaires. Comprehensive neurodevelopmental assessments were completed between 22 and 26 months corrected age. The primary and secondary composite outcomes were death or severe respiratory morbidity and death or moderate-severe neurodevelopmental impairment, respectively, at 22-26 months corrected age. RESULTS: One hundred and twenty-one randomized participants (azithromycin, N = 60; placebo, N = 61) were included in the intent-to-treat analysis. There were no significant differences in death or serious respiratory morbidity (34.8 vs 30.4%, p = 0.67) or death or moderate-severe neurodevelopmental impairment (47 vs 33%, p = 0.11) between the azithromycin and placebo groups. Among all trial participants, tracheal aspirate Ureaplasma-positive infants experienced a higher frequency of death or serious respiratory morbidity at 22-26 months corrected age (58%) than tracheal aspirate Ureaplasma-negative infants (34%) or non-intubated infants (21%) (p = 0.028). CONCLUSIONS: We did not observe strong evidence of a difference in long-term pulmonary and neurodevelopment outcomes in preterm infants treated with azithromycin in the first week of life compared to placebo. IMPACT: No strong evidence of a difference in long-term pulmonary and neurodevelopment outcomes was identified at 22-26 months corrected age in infants treated with azithromycin in the first week of life compared to placebo. The RCT is the first study of 2-year pulmonary and neurodevelopmental outcomes of azithromycin treatment in ELGANs. Provides evidence that ELGANs with lower respiratory tract Ureaplasma have the most frequent serious respiratory morbidity in the first 2 years of life, suggesting that a Phase III trial of azithromycin to prevent BPD targeting this population is warranted.

Targeting IL-17A attenuates neonatal sepsis mortality induced by IL-18.

Interleukin (IL)-18 is an important effector of innate and adaptive immunity, but its expression must also be tightly regulated because it can potentiate lethal systemic inflammation and death. Healthy and septic human neonates demonstrate elevated serum concentrations of IL-18 compared with adults. Thus, we determined the contribution of IL-18 to lethality and its mechanism in a murine model of neonatal sepsis. We find that IL-18-null neonatal mice are highly protected from polymicrobial sepsis, whereas replenishing IL-18 increased lethality to sepsis or endotoxemia. Increased lethality depended on IL-1 receptor 1 (IL-1R1) signaling but not adaptive immunity. In genome-wide analyses of blood mRNA from septic human neonates, expression of the IL-17 receptor emerged as a critical regulatory node. Indeed, IL-18 administration in sepsis increased IL-17A production by murine intestinal γδT cells as well as Ly6G(+) myeloid cells, and blocking IL-17A reduced IL-18-potentiated mortality to both neonatal sepsis and endotoxemia. We conclude that IL-17A is a previously unrecognized effector of IL-18-mediated injury in neonatal sepsis and that disruption of the deleterious and tissue-destructive IL-18/IL-1/IL-17A axis represents a novel therapeutic approach to improve outcomes for human neonates with sepsis.

Congenital Cutaneous Candidiasis: Prompt Systemic Treatment Is Associated With Improved Outcomes in Neonates.

BACKGROUND: Congenital cutaneous candidiasis (CCC) is a challenging diagnosis due to various rash presentations. Inadequate early treatment is associated with high rates of dissemination and death. The effects of early diagnosis, dermatologic presentation, and antifungal treatment on outcomes are lacking. METHODS: CCC cases were reviewed from 2 academic neonatal intensive care units (NICUs) from 2004 to 2015. We defined CCC as a diffuse rash involving the body, extremities, face or scalp, and/or funisitis, presenting in the first week (≤7 days), with identification of Candida species from skin or mucous membrane cultures, and/or by culture or staining of the placenta or umbilical cord. RESULTS: CCC occurred in 0.1% of all NICU admissions (21 of 19 303) and 0.6% of infants <1000 grams birth weight. Median gestational age of CCC infants was 26 3/7 (range, 23 0/7-40 4/7) weeks. Skin findings were commonly present on the day of birth [median (range): 0 (0-6) days], appearing most frequently as a desquamating, maculopapular, papulopustular, and/or erythematous diffuse rash. When systemic antifungal therapy was started empirically at the time of rash presentation and continued for a median (interquartile range) of 14 (14-15) days, all patients survived and none developed dissemination. Delaying systemic treatment, exclusive use of nystatin, and treating for <10 days was associated with Candida bloodstream dissemination. CONCLUSIONS: CCC is an invasive infection that presents as a diffuse rash in preterm and term infants. Prompt systemic antifungal treatment at the time of skin presentation for ≥14 days prevents dissemination and Candida-related mortality.

Epithelial PIK3R1 (p85) and TP53 Regulate Survivin Expression during Adaptation to Ileocecal Resection.

Intestinal adaptation to small-bowel resection (SBR) after necrotizing enterocolitis expands absorptive surface areas and promotes enteral autonomy. Survivin increases proliferation and blunts apoptosis. The current study examines survivin in intestinal epithelial cells after ileocecal resection. Wild-type and epithelial Pik3r1 (p85α)-deficient mice underwent sham surgery or 30% resection. RNA and protein were isolated from small bowel to determine levels of ß-catenin target gene expression, activated caspase-3, survivin, p85α, and Trp53. Healthy and post-resection human infant small-bowel sections were analyzed for survivin, Ki-67, and TP53 by immunohistochemistry. Five days after ileocecal resection, epithelial levels of survivin increased relative to sham-operated on mice, which correlated with reduced cleaved caspase-3, p85α, and Trp53. At baseline, p85α-deficient intestinal epithelial cells had less Trp53 and more survivin, and relative responses to resection were blunted compared with wild-type. In infant small bowel, survivin in transit amplifying cells increased 71% after SBR. Resection increased proliferation and decreased numbers of TP53-positive epithelial cells. Data suggest that ileocecal resection reduces p85α, which lowers TP53 activation and releases survivin promoter repression. The subsequent increase in survivin among transit amplifying cells promotes epithelial cell proliferation and lengthens crypts. These findings suggest that SBR reduces p85α and TP53, which increases survivin and intestinal epithelial cell expansion during therapeutic adaptation in patients with short bowel syndrome.

Neonatal CD71+ Erythroid Cells Do Not Modify Murine Sepsis Mortality.

Sepsis is a major cause of neonatal mortality and morbidity worldwide. A recent report suggested that murine neonatal host defense against infection could be compromised by immunosuppressive CD71(+) erythroid splenocytes. We examined the impact of CD71(+) erythroid splenocytes on murine neonatal mortality to endotoxin challenge or polymicrobial sepsis and characterized circulating CD71(+) erythroid (CD235a(+)) cells in human neonates. Adoptive transfer or an Ab-mediated reduction in neonatal CD71(+) erythroid splenocytes did not alter murine neonatal survival to endotoxin challenge or polymicrobial sepsis challenge. Ex vivo immunosuppression of stimulated adult CD11b(+) cells was not limited to neonatal splenocytes; it also occurred with adult and neonatal bone marrow. Animals treated with anti-CD71 Ab showed reduced splenic bacterial load following bacterial challenge compared with isotype-treated mice. However, adoptive transfer of enriched CD71(+) erythroid splenocytes to CD71(+)-reduced animals did not reduce bacterial clearance. Human CD71(+)CD235a(+) cells were common among cord blood mononuclear cells and were shown to be reticulocytes. In summary, a lack of effect on murine survival to polymicrobial sepsis following adoptive transfer or diminution of CD71(+) erythroid splenocytes under these experimental conditions suggests that the impact of these cells on neonatal infection risk and progression may be limited. An unanticipated immune priming effect of anti-CD71 Ab treatment, rather than a reduction in immunosuppressive CD71(+) erythroid splenocytes, was likely responsible for the reported enhanced bacterial clearance. In humans, the well-described rapid decrease in circulating reticulocytes after birth suggests that they may have a limited role in reducing inflammation secondary to microbial colonization.

Oligodendroglial maldevelopment in the cerebellum after postnatal hyperoxia and its prevention by minocycline.

According to recent research, brain injury after premature birth often includes impaired growth of the cerebellum. However, causes of cerebellar injury in this population are poorly understood. In this study, we analyzed whether postnatal hyperoxia perturbs white matter development of the cerebellum, and whether cerebellar glial damage can be prevented by minocycline. We used a hyperoxia model in neonatal rats providing 24 h exposure to fourfold increased oxygen concentration (80% O2) from P6 to P7, followed by recovery in room air until P9, P11, P15, P30. Injections with minocycline were performed at the beginning and 12 h into hyperoxia exposure. Hyperoxia induced oxidative stress in the cerebellum at P7 as evidenced by increased nitrotyrosine concentrations. Numbers of proliferating, NG2+Ki67+ oligodendroglial precursor cells were decreased at P7 after hyperoxia and at P11 following recovery in room air. Numbers of mature, CC1+ oligodendrocytes were diminished in recovering hyperoxia rats, and myelin basic protein expression was still decreased at P30. Electron microscopy analysis of myelinated fibers at P30 revealed thinner myelin sheath after hyperoxia. Long-term injury of the cerebellum by neonatal hyperoxia was confirmed by reduced volumes in MRI measurements at P30. In response to 80% O2, expression of platelet-derived growth factor (PDGF)-A was largely reduced in cerebellar tissue and also in cultured cerebellar astrocytes. Treatment with minocycline during hyperoxia prevented oxidative stress, attenuated oligodendroglial injury, and improved astroglial PDGF-A levels. In conclusion, early hyperoxia causes white matter damage in the cerebellum with astroglial dysfunction being involved, and both can be prevented by treatment with minocycline. Neonatal exposure to hyperoxia causes hypomyelination of the cerebellum. Reduced astroglial growth factor production but not microglial inflammation seems to contribute to oligodendroglial damage, and minocycline rescues oligodendroglia development in the cerebellum after hyperoxia.

Maternal influences on fetal microbial colonization and immune development.

While critical for normal development, the exact timing of establishment of the intestinal microbiome is unknown. For example, although preterm labor and birth have been associated with bacterial colonization of the amniotic cavity and fetal membranes for many years, the prevailing dogma of a sterile intrauterine environment during normal term pregnancies has been challenged more recently. While found to be a key contributor of evolution in the animal kingdom, maternal transmission of commensal bacteria may also constitute a critical process during healthy pregnancies in humans with yet unclear developmental importance. Metagenomic sequencing has elucidated a rich placental microbiome in normal term pregnancies likely providing important metabolic and immune contributions to the growing fetus. Conversely, an altered microbial composition during pregnancy may produce aberrant metabolites impairing fetal brain development and life-long neurological outcomes. Here we review the current understanding of microbial colonization at the feto-maternal interface and explain how normal gut colonization drives a balanced neonatal mucosal immune system, while dysbiosis contributes to aberrant immune function early in life and beyond. We discuss how maternal genetics, diet, medications, and probiotics inform the fetal microbiome in preparation for perinatal and postnatal bacterial colonization.

STAT6 deficiency ameliorates severity of oxazolone colitis by decreasing expression of claudin-2 and Th2-inducing cytokines.

Patients suffering from ulcerative colitis (UC) exhibit chronic colonic inflammation caused by a dysregulated mucosal immune response and epithelial barrier disruption. Th2 cytokines, including IL-13, have been implicated in the pathogenesis of UC. IL-13 induces phosphorylation of STAT6, and we previously demonstrated increased epithelial p-STAT6 in children with UC. In this study, we investigated the role of STAT6 in oxazolone colitis, a murine model of UC, by inducing colitis in STAT6-deficient (STAT6(-/-)) and wild type (WT) mice. We observed increased epithelial cell, T cell, macrophage, and NKT cell STAT6 phosphorylation, as well as increased p-STAT6(+) IL-13-producing NKT cells, in colitic WT mice. Colitis was attenuated in STAT6(-/-) mice, with improvements in weight, colon length, and histopathology. There was decreased induction of the pore-forming tight junction protein claudin-2 in STAT6(-/-) mice. Similarly, short hairpin RNA STAT6 knockdown reduced claudin-2 induction and transepithelial resistance decrease in IL-13-treated human T84 cells. Tissue expression of IL-13, IFN-γ, IL-17, and IL-10 mRNA was similarly induced in WT and STAT6(-/-) colitic mice; however, we observed increased mRNA expression for the Th2-inducing cytokines IL-33 and thymic stromal lymphopoietin in WT mice with colitis, which was abrogated in STAT6(-/-) mice. Mesenteric lymph node cells from STAT6(-/-) mice with colitis exhibited reduced secretion of IL-4, IL-5, IL-13, and IFN-γ. IL-33 augmented mesenteric lymph node cell secretion of IL-5, IL-13, IL-6, and IFN-γ. These data implicate STAT6 in the pathogenesis of colitis in vivo with important roles in altering epithelial barrier function and regulating Th2-inducing cytokine production.

Predicting posttransplantation diabetes mellitus by regulatory T-cell phenotype: implications for metabolic intervention to modulate alloreactivity.

Chronic inflammation and decreased frequency of regulatory T cells (Tregs) in visceral adipose tissue contribute to the propagation of insulin resistance to diabetes mellitus. We tested the hypothesis that new-onset posttransplantation diabetes mellitus (PTDM) is associated with measurable changes in Treg subsets after allogeneic hematopoietic stem cell transplantation (HSCT). PTDM before day 100 and Treg phenotype at engraftment were determined in 36 HSCT recipients without preceding history of diabetes mellitus. Among patients with new-onset PTDM (N = 24), the frequency of circulating CLA(+) (skin-homing) Tregs was decreased (1.53% vs 3.99%; P = .002) and the percentage of α(4)ß(7)(+) (gut-homing) Tregs was increased (17.9% vs 10.7%; P = .048). In multivariate analysis, patients with PTDM continued to demonstrate elevated ratios of α(4)ß(7)(+) Tregs to CLA(+) Tregs (odds ratio, 18.1; P = .020). PTDM is associated with altered immune regulation after HSCT and could represent a target to modulate alloreactivity.

Incidence of catheter-related bloodstream infections in neonates following removal of peripherally inserted central venous catheters.

OBJECTIVES: Catheter-associated bloodstream infections are a significant source of morbidity and healthcare cost in the neonatal ICU. Previous studies examining the prevalence of bloodstream infections after removal of peripherally inserted central venous catheters in neonates are equivocal. DESIGN: A retrospective cohort study. PATIENTS: All infants with peripherally inserted central venous catheters treated at the Vanderbilt neonatal ICU between 2007 and 2009. MEASUREMENTS AND MAIN RESULTS: We evaluated the following outcomes: 1) bloodstream infections, 2) culture-negative sepsis, 3) number of sepsis evaluations, and 4) number of significant apnea/bradycardia events comparing odds ratios between 72 hours before and 72 hours after peripherally inserted central venous catheter removal. We analyzed a total of 1,002 peripherally inserted central venous catheters in 856 individual infants with a median (interquartile range) gestational age of 31 weeks (28-37 wk) and a median birth weight of 1,469 g (960-2,690 g). Comparing 72 hours before with 72 hours after peripherally inserted central venous catheter removal did not show a difference in the prevalence of bloodstream infections (9 vs 3, p = 0.08), prevalence of culture-negative sepsis (37 vs 40, p = 0.73), number of sepsis evaluations (p = 0.42), or number of apnea/bradycardia events (p = 0.32). However, in peripherally inserted central venous catheter not used for delivery of antibiotics, there was a 3.83-fold increase in odds for culture-negative sepsis following peripherally inserted central venous catheter removal (95% confidence interval, 1.48-10.5; p = 0.001). For infants less than 1,500 g birth weight (very low birth weight), odds for culture-negative sepsis increased to 6.3-fold following removal of peripherally inserted central venous catheters not used for antibiotic delivery (95% confidence interval, 1.78-26.86; p < 0.01). CONCLUSIONS: Although these data do not support the routine use of antibiotics for sepsis prophylaxis prior to peripherally inserted central venous catheter removal, they suggests that very low birth weight infants not recently exposed to antibiotics are at increased odds for associated adverse events following discontinuation of their peripherally inserted central venous catheter.

Necrotising enterocolitis is characterised by disrupted immune regulation and diminished mucosal regulatory (FOXP3)/effector (CD4, CD8) T cell ratios.

BACKGROUND: Necrotising enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Immaturity of gastrointestinal immune regulation may predispose preterm infants to NEC as FOXP3 T regulatory cells (Treg) are critical for intestinal immune homoeostasis. OBJECTIVE: To investigate the hypothesis that abnormal developmental regulation of lamina propria Treg would define premature infants with NEC. DESIGN: Lamina propria mononuclear cell populations from surgically resected ileum from 18 patients with NEC and 30 gestational age-matched non-NEC surgical controls were prospectively isolated. Polychromatic flow cytometry was performed to phenotype and analyse lamina propria T cell populations. The cytokine gene expression profile in NEC tissue was compared with that of non-NEC controls. RESULTS: The total number of Treg, CD4, or CD8 T cells in each ileum section was independent of gestational age, age or postmenstrual age and similar between patients with NEC and controls. In contrast, the ratio of Treg to CD4 T cells or Treg to CD8 T cells was significantly lower in NEC ileum than in infants without NEC (medians 2.9% vs 6.6%, p=0.001 and medians 6.6% vs 25.9%, p<0.001, respectively). For any given number of CD4 or CD8 T cells, Treg were, on average, 60% lower in NEC ileum than in controls. NEC tissue cytokine gene expression profiles were characteristic of inhibited Treg development or function. Treg/CD4 and Treg/CD8 ratios recovered between initial resection for NEC and reanastomosis. CONCLUSION: The proportion of lamina propria Treg is significantly reduced in the ileum of premature infants with NEC and may contribute to the excessive inflammatory state of this disease.

Smad7 inhibits autocrine expression of TGF-ß2 in intestinal epithelial cells in baboon necrotizing enterocolitis.

Preterm infants may be at risk of necrotizing enterocolitis (NEC) due to deficiency of transforming growth factor-ß 2 (TGF-ß(2)) in the developing intestine. We hypothesized that low epithelial TGF-ß(2) expression in preterm intestine and during NEC results from diminished autocrine induction of TGF-ß(2) in these cells. Premature baboons delivered at 67% gestation were treated per current norms for human preterm infants. NEC was diagnosed by clinical and radiological findings. Inflammatory cytokines, TGF-ß(2), Smad7, Ski, and strawberry notch N (SnoN)/Ski-like oncoprotein (SKIL) was measured using quantitative reverse transcriptase-polymerase chain reaction, immunoblots, and immunohistochemistry. Smad7 effects were examined in transfected IEC6 intestinal epithelial cells in vitro. Findings were validated in archived human tissue samples of NEC. NEC was recorded in seven premature baboons. Consistent with existing human data, premature baboon intestine expressed less TGF-ß(2) than term intestine. TGF-ß(2) expression was regulated in epithelial cells in an autocrine fashion, which was interrupted in the premature intestine and during NEC due to increased expression of Smad7. LPS increased Smad7 binding to the TGF-ß(2) promoter and was associated with dimethylation of the lysine H3K9, a marker of transcriptional silencing, on the nucleosome of TGF-ß(2). Increased Smad7 expression in preterm intestine was correlated with the deficiency of SnoN/SKIL, a repressor of the Smad7 promoter. Smad7 inhibits autocrine expression of TGF-ß(2) in intestinal epithelial cells in the normal premature intestine and during NEC. Increased Smad7 expression in the developing intestine may be due to a developmental deficiency of the SnoN/SKIL oncoprotein.

Multidrug-Resistant Bacterial Infections Among Very Low Birthweight Infants With Late-Onset Sepsis in Johannesburg, South Africa.

Background: An estimated 2.4 million babies died within the first 28 days of life in 2020. The third leading cause of neonatal death continues to be neonatal sepsis. Sepsis-causing bacterial pathogens vary temporally and geographically and, with a rise in multidrug-resistant organisms (MDROs), pose a threat to the neonatal population. Methods: This was a single-center, retrospective study of very low birth weight (VLBW) infants with late-onset sepsis (LOS) admitted to a neonatal unit in South Africa. We aimed to calculate the prevalence of multidrug-resistant (MDR) infections in this population. The data collected included demographic and clinical characteristics, length of hospital stay, risk factors for MDRO and mortality, and microbiology results. Logistic regression was used to assess the association between prespecified risk factors with MDR infections and mortality. Results: Of 2570 VLBW infants admitted, 34% had LOS, of which 33% was caused by MDROs. Infection with Acinetobacter spp., Pseudomonas spp., extended-spectrum beta-lactamase Klebsiella spp., or Escherichia coli was associated with the highest mortality in the LOS cohort. Infants with congenital infections (adjusted odds ratio [aOR], 5.13; 95% CI, 1.19-22.02; P = .028) or a history of necrotizing enterocolitis (aOR, 2.17; 95% CI, 1.05-4.49; P = .037) were at significantly higher risk for MDR infections. Conclusions: More than one-third of LOS cases in VLBW infants were caused by MDROs in this study. MDR infections cause substantial neonatal mortality. Antimicrobial stewardship programs, infection control protocols, and ongoing surveillance are needed to prevent further emergence and spread of MDR infections worldwide.

Cytomegalovirus infection.

Although commonly asymptomatic, congenital CMV infection is the leading cause of nonhereditary SNHL. Other sequelae that may be evident only after the neonatal period can include chorioretinitis, neurodevelopmental delay with mental or motor impairment, and microcephaly. (13) • Congenital CMV infection is confirmed by detection of the virus in urine, blood, or saliva within the first 3 weeks of life by culture or polymerase chain reaction. A positive test does not necessarily confirm symptomatic CMV disease or need for treatment. (13) • Postnatal CMV infections transmitted through human milk have been reported and may be clinically relevant in extremely premature infants; however, the risk-benefit ratio of pasteurizing human milk for the prevention of postnatal CMV infection is unclear. • Ganciclovir, valganciclovir, foscarnet, cidofovir, and CMV hyperimmune globulin are effective in treating or preventing CMV infections in the immunocompromised host, but require close monitoring for associated toxicities. Treatment for congenital CMV is associated with significant toxicity and uncertain effectiveness. • Based on strong evidence, anticipatory guidance for congenital CMV infection should include hearing tests and neurodevelopmental assessments until school age. (3) In patients with symptomatic congenital CMV infection, lifelong ophthalmologic screening should be included. (4) • Based primarily on consensus, owing to lack of relevant clinical studies, it is not recommended to withhold human milk produced by CMV-seropositive mothers from healthy term infants. (5)(6) • Based on some research evidence, as well as consensus, treatment for congenital CMV is recommended only in symptomatic infants with central nervous system involvement. (9)