Temporal development of the human gut microbiome from infancy to childhood is driven by a variety of factors. We surveyed the fecal microbiome of 729 Chinese children aged 0–36 months, aiming to identify the age-specific patterns of microbiota succession, and evaluate the impact of birth mode, gender, geographical location, and gastrointestinal tract symptoms on the shaping of the gut microbiome. We demonstrated that phylogenetic diversity of the gut microbiome increased gradually over time, which was accompanied by an increase in Bacteroidetes and a reduction in Proteobacteria species. Analysis of community-wide phenotypes revealed a succession from aerobic bacteria and anaerobic bacteria to facultative anaerobes, and from Gram-negative to Gram-positive species during gut microbiota development in early childhood. The metabolic functions of the gut microbiome shifted tremendously alongside early physiological development, including an increase in alanine, aspartate, and glutamate metabolism, and a reduction in glutathione, fatty acid, and tyrosine metabolism. During the first year of life, the Bacteroidetes phylum was less abundant in children born by casarean section compared with those delivered vaginally. The Enterococcaceae family, a group of facultative anaerobic microorganisms with pathogenic potential, was predominant in preterm infants. No measurable effect of maternal antibiotic exposure on gut microbiota development was found in the first 3 years of life. The relative abundances of Coriobacteriaceae and Streptococcaceae families, and Megasphaera genus were found to be higher in girls than in boys. Among the three first-tier Chinese cities, children born and fed in Beijing had a higher abundance of Enterococcaceae and Lachnospiraceae families, and Shenzhen children had a higher abundance of Fusobacteriaceae. The families Alcaligenaceae, Bacteroidaceae, and Porphyromonadaceae were more abundant in children with constipation, whereas the relative abundance of the Clostridium genus was higher in those with diarrhea.

To explore the influences of prenatal antibiotic exposure, the intensity of prenatal and postnatal antibiotic exposure on gut microbiota of preterm infants and whether gut microbiota and drug resistant strains in the neonatal intensive care unit (NICU) over a defined period are related. Among 28 preterm infants, there were two groups, the PAT (prenatal antibiotic therapy) group (12 cases), and the PAF (prenatal antibiotic free) group (12 cases). Fecal samples from both groups were collected on days 7 and 14. According to the time of prenatal and postnatal antibiotic exposure, cases were divided into two groups, H (high) group (11 cases) and L (low) group (11 cases), and fecal samples on day 14 were collected. Genomic DNA was extracted from the fecal samples and was subjected to high throughput 16S rRNA amplicon sequencing. Bioinformatics methods were used to analyze the sequencing results. Prenatal and postnatal antibiotic exposure exercised influence on the early establishment of intestinal microflora of preterm infants. Bacteroidetes decreased significantly in the PAT group (p < 0.05). The number of Bifidobacterium significantly decreased in the PAT group and H group (p < 0.05). The early gut microbiota of preterm infants with prenatal and postnatal antibiotic exposure was similar to resistant bacteria in NICU during the same period. Prenatal and postnatal antibiotic exposure may affect the composition of early gut microbiota in preterm infants. Antibiotic-resistant bacteria in NICU may play a role in reshaping the early gut microbiota of preterm infants with prenatal and postnatal antibiotic exposure.

Currently, prophylactic use of drugs to promote a healthy gut microbiota and immune system in preterm infants is hot debated, among which lactoferrin is a promising supplementation. However, the effect and safety of lactoferrin to prevent late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) in preterm infants remains controversial.[1] Databases including Medline, Ovid-Embase, The Cochrane Library, CBM, CNKI, and VIP database of Chinese Journal were searched to collect randomized controlled trials (RCTs) about lactoferrin for preventing LOS and NEC in preterm infants. Languages of included RCTs were restricted to English and Chinese. Meta-analysis was conducted by Rev Man 5.3 software. The Mantel–Haenszel method with random-effects model was used to calculate pooled relative risks (RRs) and 95% confidence intervals (CIs). A total of 9 RCTs, involving 1834 patients, were included. Pooled analysis showed that prophylactic lactoferrin could significantly reduce the incidence all culture-proven LOS (41/629 [6.5%] vs 96/659 [15.3%]; RR 0.47; 95% CI 0.33–0.67; P < .01) and NEC (stage II or more) (9/448 [2.0%] vs 26/462 [5.6%]; RR 0.40; 95% CI 0.18–0.86; P < .01). Lactoferrin was also associated with a significantly decreased hospital-acquired infection (16/139 [11.5%] vs 35/140 [25%]; RR 0.47; 95% CI 0.27–0.80; P < .01); and infection-related mortality (4/474 [0.8%] vs 25/505 [4.9%]; RR 0.24; 95% CI 0.04–1.32; P < .01, I = 53%). Lactoferrin could shorten time to reach full enteral feeding (weighted mean difference [WMD] = −2.11, 95% CI −3.12 to −1.10; P < .01) and showed a decreasing trend of duration of hospitalization (WMD = −1.69, 95% CI −6.87 to 3.50; P < .01; I = 95%). Lactoferrin did not have a significant effect on all-cause mortality (22/625 [3.5%] vs 35/647 [5.4%]; RR 0.70; 95% CI 0.38–1.30; P = .16; I = 13%). None of the included trials reported any confirmed adverse effects caused by the supplemented lactoferrin or probiotics. Current evidence indicates that lactoferrin could significantly reduce the incidence of NEC and LOS, and decrease the risk of hospital-acquired infection and infection-related mortality in premature infants without obvious adverse effects.

Background: Necrotizing enterocolitis (NEC) remains a life-threatening disease in neonates. Numerous studies have shown a correlation between the intestinal microbiota and NEC, but the causal link remains unclear. This study aimed to demonstrate the causal role of gut microbiota in NEC and explore potential mechanisms involved. Methods: Eighty-one fecal samples from patients with NEC and eighty-one matched controls (matched to the NEC infants by gestational age, birth weight, date of birth, mode of delivery and feeding patterns) were collected. To explore if altered gut microbiota contributes to the pathogenesis of NEC, fecal microbiota transplantation (FMT) was carried out in germ-free (GF) mice prior to a NEC-induction protocol that included exposure to hypoxia and cold stress. Butyric acid was also administered to demonstrate its role in NEC. The fecal microbiota from patients and mice were analyzed by 16S rRNA gene sequencing analysis. Short chain fatty acid (SCFA) levels were measured by gas chromatography-mass spectrometry (GC–MS). The ontogeny of T cells and regulatory T cells (T_regs) in lamina propria mononuclear cells (LPMC) from the ileum of patients and mice were isolated and analyzed by flow cytometry.The transcription of inflammatory cytokines was quantified by qRT-PCR. Results: NEC patients had increased Proteobacteria and decreased Firmicutes and Bacteroidetes compared to fecal control samples, and the level of butyric acid in the NEC group was lower than the control group. FMT in GF mice with samples from NEC patients achieved a higher histological injury scores when compared to mice that received FMT with control samples. Alterations in microbiota and butyrate levels were maintained in mice following FMT. The ratio of T_reg/CD4⁺T (T_helper) cells was reduced in both NEC patients and mice modeling NEC following FMT. Conclusions: The microbiota was found to have NEC and the microbial butyrate-T_reg axis was identified as a potential mechanism for the observed effects.

Background: Early onset sepsis (EOS) remains a major cause of mortality and morbidity in neonates, and traditional clinical markers effective for adults are less effective in these patients. This study aimed to assess the value of individual plasma biomarkers as well as biomarker combinations for predicting EOS in neonates. Methods: This prospective study included 151 neonates with suspected EOS. Plasma levels of interleukin (IL)-27, IL-6, IL-8, tumor necrosis factor (TNF)-α, heat shock protein (HSP) 70, macrophage inflammatory protein (MIP)-1α, MIP-1β, granzyme B, and matrix metalloproteinase (MMP)-8 were measured through multiplex cytokine profiling and assessed along with C-reactive protein (CRP) and procalcitonin (PCT). Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive ability of biomarkers individually and in combination. Logistic regression model was constructed to identify independent predictors of EOS. Results: The proven sepsis and probable sepsis groups were combined to form the infected group (n = 68), and the possible sepsis and low-risk sepsis groups were combined to form the uninfected group (n = 83). The ROC area under the curve was 0.747 for IL-27 (P <0.01). In addition, IL-6, TNF-α, HSP 70, MMP-8, PCT, and CRP were significantly predictive of EOS, whereas IL-8, granzyme B, MIP-1α, and MIP-1β were not. Both IL-27 and PCT were identified as independent predictors of EOS in the multivariate model, and the combined use of these markers showed significantly increased predictive ability for EOS. Conclusion: Our results indicate that elevated IL-27 strongly correlates with EOS and may provide additional diagnostic value along with PCT.