Weight shapes the intestinal microbiome in preterm infants: results of a prospective observational study.

BACKGROUND: The intestinal microbiome in preterm infants differs markedly from term infants. It is unclear whether the microbiome develops over time according to infant specific factors. METHODS: We analysed (clinical) metadata - to identify the main factors influencing the microbiome composition development - and the first meconium and faecal samples til the 4th week via 16 S rRNA amplican sequencing. RESULTS: We included 41 infants (gestational age 25-30 weeks; birth weight 430-990 g. Birth via Caesarean section (CS) was associated with placental insufficiency during pregnancy and lower BW. In meconium samples and in samples from weeks 2 and 3 the abundance of Escherichia and Bacteroides (maternal faecal representatives) were associated with vaginal delivery while Staphylococcus (skin microbiome representative) was associated with CS. Secondly, irrespective of the week of sampling or the mode of birth, a transition was observed as children children gradually increased in weight from a microbiome dominated by Staphylococcus (Bacilli) towards a microbiome dominated by Enterobacteriaceae (Gammaproteobacteria). CONCLUSIONS: Our data show that the mode of delivery affects the meconium microbiome composition. They also suggest that the weight of the infant at the time of sampling is a better predictor for the stage of progression of the intestinal microbiome development/maturation than postconceptional age as it less confounded by various infant-specific factors.

Increased incidence of necrotizing enterocolitis in the Netherlands after implementation of the new Dutch guideline for active treatment in extremely preterm infants: Results from three academic referral centers.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a severe inflammatory disease, mostly occurring in preterm infants. The Dutch guidelines for active treatment of extremely preterm infants changed in 2006 from 26+0 to 25+0weeks of gestation, and in 2010 to 24+0 of gestation. We aimed to gain insight into the incidence, clinical outcomes and treatment strategies, in three academic referral centers in the Netherlands over the last nine years. METHODS: We performed a multicenter retrospective cohort study of all patients with NEC (Bell stage ≥2a) in three academic referral centers diagnosed between 2005 and 2013. Outcome measures consisted of incidence, changes in clinical presentation, treatment strategies and mortality. RESULTS: Between 2005 and 2013 14,161 children were admitted to the neonatal intensive care unit in the three centers. The overall percentage of children born at a gestational age of 24weeks and 25weeks increased with 1.7% after the introduction of the guidelines in 2006 and 2010. The incidence of NEC increased significantly (period 2005-2007: 2.1%; period 2008-2010 3.9%; period 2011-2013: 3.4%; P=0.001). We observed a significant decrease of peritoneal drainages (↓16%; P=0.001) and a decrease of laparotomies (↓24%; P=0.002). The mortality rate (33% in 2011-2013) remained unchanged. CONCLUSION: The incidence of NEC significantly increased in the last nine years. The increase in incidence of NEC seemed to be related to an increase in infants born at a gestational age of 24 and 25weeks. The percentage of patients needing surgery decreased, while 30-day mortality did not change. LEVEL OF EVIDENCE: Level IV.

The relation between splanchnic ischaemia and intestinal damage in necrotising enterocolitis.

OBJECTIVES: The underlying pathophysiology of necrotising enterocolitis (NEC) remains incompletely understood, particularly the role of intestinal perfusion. We aimed to determine the relation between cerebral and splanchnic fractional tissue oxygen extraction (FTOE), a marker for tissue underperfusion, with intestinal fatty acid-binding protein in plasma (I-FABPp), a marker for intestinal damage, in infants with NEC. Furthermore, we investigated the combined courses of cerebral and splanchnic FTOE values and I-FABPp levels in uncomplicated (conservative treatment) and complicated NEC (surgery or death). DESIGN: This study was part of a prospective observational cohort study. PATIENTS: We included 19 preterm infants with NEC (9 uncomplicated, 10 complicated). INTERVENTIONS: Using near-infrared spectroscopy, we measured regional cerebral and splanchnic tissue oxygen saturations continuously for 48 h after NEC onset. We measured I-FABPp levels simultaneously. MAIN OUTCOME MEASURES: We used Spearman correlation tests to calculate correlation coefficients between FTOE values and I-FABPp levels in uncomplicated and complicated NEC. RESULTS: Median (range) gestational age was 28 (25-36) weeks and median (range) birth weight was 1290 (740-2400) g. Cerebral and splanchnic FTOE values correlated strongly with I-FABPp levels (rho between .745 and 0.900; p<0.001-0.037) during the first 16 h after NEC onset. Thereafter, in uncomplicated NEC, splanchnic FTOE values increased while I-FABPp levels decreased concomitantly. In complicated NEC both splanchnic FTOE values and I-FABPp levels decreased. CONCLUSIONS: Combining cerebral and splanchnic FTOE values with I-FABPp levels, gives insight in the pathological chain of events resulting in progression or recovery of intestinal ischaemia in NEC. TRIAL REGISTRATION NUMBER: NTR3239.

Paneth cells in the developing gut: when do they arise and when are they immune competent?

BACKGROUND: Little is known about the perinatal development of Paneth cells (PCs) during gestation and the relation with necrotizing enterocolitis (NEC). We aimed to investigate when PCs arise and when they become immune competent during gestation. METHODS: We included 57 samples of ileum tissue of fetuses/infants with a gestional age (GA) between 9 and 40 wk taken as part of a standard autopsy procedure. Hematoxylin-eosin staining and anti-human defensin 5 immunohistochemistry were performed. We performed a semi-quantitative assessment of (immune-competent) PC numbers per 10 crypts per tissue section per GA. RESULTS: The number of PCs and the number of immune-competent PCs increased with increasing GA (Spearman's ρ = 0.41, P = 0.002 and ρ = 0.61, P < 0.001, respectively). Whereas significantly higher PC numbers were observed after 37 wk gestation (median 7, range 0-12) compared to preterm infants (median 0, range 0-15; P = 0.002), we counted higher numbers of immune-competent PCs already in infants with GA above 29 wk (median 6, range 0-18) compared to infants with GA under 29 wk (median 2, range 0-9; P < 0.001). CONCLUSION: The significant increase of immune-competent PCs starting from a GA of 29 wk mimics the rise in incidence of NEC during a similar postmenstrual age in preterm infants.

A Necrotizing Enterocolitis-Associated Gut Microbiota Is Present in the Meconium: Results of a Prospective Study.

BACKGROUND: Anomalous intestinal microbiota development is supposedly associated with development of necrotizing enterocolitis (NEC). Our aim in this study was to identify the intestinal microbiota of patients at risk for NEC. METHODS: In a prospective trial that investigated prognostic factors for development of NEC in high-risk neonates (NTR4153), 11 NEC cases were gestational age/birthweight matched with controls (ratio of 1:2). Feces were collected twice a week. We used the first feces sample of each patient (meconium), as well as the last 2 feces samples prior to development of NEC. DNA was extracted, and the bacterial 16S rRNA genes were analyzed on a MiSeq sequencer. RESULTS: The presence and abundance of Clostridium perfringens (8.4%) and Bacteroides dorei (0.9%) in meconium were increased in neonates who developed NEC compared with controls (0.1% and 0.2%; both species, P < .001). In post-meconium samples, the abundance of staphylococci became negatively associated with NEC development (P = .1 and P = .01 for consecutive samples); Clostridium perfringens continued to be more prevalent in NEC cases. Early enteral feeding and, in particular, breast milk were correlated with an increase in lactate-producing bacilli in post-meconium samples (ρ = -0.45; P = .004). CONCLUSIONS: A NEC-associated gut microbiota can be identified in meconium samples; C. perfringens continues to be associated with NEC from the first meconium till just before NEC onset. In contrast, in post-meconium, increased numbers of staphylococci were negatively associated with NEC. These findings suggest causality but this causality should be verified in trials of induced infection in animals, targeted antibiotics, and/or probiotics. CLINICAL TRIALS REGISTRATION: CALIFORNIA trial, registered under trial number NTR4153 in the Dutch Trial Registry.