The authors note that on page 12527, left column, second full paragraph, line 7, "Sequences meeting the above criteria were further classified by the Ribosomal Database Project (RDP) Naive Bayesian Classifier version 2.5 using training set 9 (46) from phylum to genus level." should instead appear as "Sequences meeting the above criteria were further classified by the Ribosomal Database Project (RDP) Naive Bayesian Classifier version 2.2 using training set 6 (46) from phylum to genus level."www.pnas.org/cgi

Summary Background Gut bacteria might predispose to or protect from necrotising enterocolitis, a severe illness linked to prematurity. In this observational prospective study we aimed to assess whether one or more bacterial taxa in the gut differ between infants who subsequently develop necrotising enterocolitis (cases) and those who do not (controls). Methods We enrolled very low birthweight (1500 g and lower) infants in the primary cohort (St Louis Children’s Hospital) between July 7, 2009, and Sept 16, 2013, and in the secondary cohorts (Kosair Children’s Hospital and Children’s Hospital at Oklahoma University) between Sept 12, 2011 and May 25, 2013. We prospectively collected and then froze stool samples for all infants. Cases were defined as infants whose clinical courses were consistent with necrotising enterocolitis and whose radiographs fulfilled criteria for Bell’s stage 2 or 3 necrotising enterocolitis. Control infants (one to four per case; not fixed ratios) with similar gestational ages, birthweight, and birth dates were selected from the population after cases were identified. Using primers specific for bacterial 16S rRNA genes, we amplified and then pyrosequenced faecal DNA from stool samples. With use of Dirichlet multinomial analysis and mixed models to account for repeated measures, we identified host factors, including development of necrotising enterocolitis, associated with gut bacterial populations. Findings We studied 2492 stool samples from 122 infants in the primary cohort, of whom 28 developed necrotising enterocolitis; 94 infants were used as controls. The microbial community structure in case stools differed significantly from those in control stools. These differences emerged only after the first month of age. In mixed models, the time-by-necrotising-enterocolitis interaction was positively associated with Gammaproteobacteria (p=0·0010) and negatively associated with strictly anaerobic bacteria, especially Negativicutes (p=0·0019). We studied 1094 stool samples from 44 infants in the secondary cohorts. 18 infants developed necrotising enterocolitis (cases) and 26 were controls. After combining data from all cohorts (166 infants, 3586 stools, 46 cases of necrotising enterocolitis), there were increased proportions of Gammaproteobacteria (p=0·0011) and lower proportions of both Negativicutes (p=0·0013) and the combined Clostridia–Negativicutes class (p=0·0051) in infants who went on to develop necrotising enterocolitis compared with controls. These associations were strongest in both the primary cohort and the overall cohort for infants born at less than 27 weeks’ gestation. Interpretation A relative abundance of Gammaproteobacteria (ie, Gram-negative facultative bacilli) and relative paucity of strict anaerobic bacteria (especially Negativicutes) precede necrotising enterocolitis in very low birthweight infants. These data offer candidate targets for interventions to prevent necrotising enterocolitis, at least among infants born at less than 27 weeks’ gestation. Funding Nation...

Objective To assess the utility of clinical predictors of persistent respiratory morbidity in extremely low gestational age newborns (ELGAN). Study Design We enrolled ELGAN (<29 weeks’ gestation) at ≤7 postnatal days and collected antenatal and neonatal clinical data through 36 weeks’ post-menstrual age. We surveyed caregivers at 3, 6, 9 and 12 months corrected age to identify post-discharge respiratory morbidity, defined as hospitalization, home support (oxygen, tracheotomy, ventilation), medications, or symptoms (cough/wheeze). Infants were classified as post-prematurity respiratory disease (PRD, the primary study outcome), if respiratory morbidity persisted over ≥2 questionnaires. Infants were classified with severe respiratory morbidity if there were multiple hospitalizations, exposure to systemic steroids or pulmonary vasodilators, home oxygen after 3 months or mechanical ventilation, or symptoms despite inhaled corticosteroids. Mixed effects models generated with data available at one day (perinatal) and 36 weeks’ postmenstrual age were assessed for predictive accuracy. Results Of 724 infants (918±234g, 26.7±1.4 weeks’ gestational age) classified for the primary outcome, 68.6% had PRD; 245/704 (34.8%) were classified as severe. Male sex, intrauterine growth restriction, maternal smoking, race/ethnicity, intubation at birth, and public insurance were retained in perinatal and 36-week models for both PRD and respiratory morbidity severity. The perinatal model accurately predicted PRD (c-statistic 0.858). Neither the 36-week model nor the addition of bronchopulmonary dysplasia (BPD) to the perinatal model improved accuracy (0.856, 0.860); c-statistic for BPD-alone was 0.907. Conclusion Both BPD and perinatal clinical data accurately identify ELGAN at risk for persistent and severe respiratory morbidity at one year. Trial registration ClinicalTrials.gov: NCT01435187

Objective: To determine patterns of respiratory medications used in neonatal intensive care unit (NICU) graduates. Study design: The Prematurity Respiratory Outcomes Program enrolled 835 babies <29 weeks gestation in the first week. Of 751 survivors, 738 (98%) completed at least 1, and 85% completed

Necrotizing enterocolitis (NEC) is a serious consequence of preterm birth and is often associated with gut bacterial microbiome alterations. However, little is known about the development of the gut virome in preterm infants, or its role in NEC. Here, using metagenomic sequencing, we characterized the DNA gut virome of 9 preterm infants who developed NEC and 14 gestational age-matched preterm infants who did not. Infants were sampled longitudinally before NEC onset over the first 11 weeks of life. We observed substantial interindividual variation in the gut virome between unrelated preterm infants, while intraindividual variation over time was significantly less. We identified viral and bacterial signatures in the gut that preceded NEC onset. Specifically, we observed a convergence towards reduced viral beta diversity over the 10 d before NEC onset, which was driven by specific viral signatures and accompanied by specific viral-bacterial interactions. Our results indicate that bacterial and viral perturbations precede the sudden onset of NEC. These findings suggest that early life virome signatures in preterm infants may be implicated in NEC.