Intestinal Microbiota And Pediatric Enterocolitis

Part Ⅰ.Patterened Intestinal Microbiota in Preterm Necrotizing Enterocolitis and Late-Onset SepsisAIM To profile postpartum pattern progression of intestinal microbiome in necrotizing enterocolitis and late-onset sepsis in preterm infants,with the aim of understanding their etiologic microbiota profiles from a dynamic perspective.METHODS 24 preterm newborns were enrolled,among whom four subsequently developed NEC,three LOS,and the remaining 17 were healthy controls.Starting from the first stool after birth and continuing till discharge,192 longitudinal fecal samples were prospectively collected from all patients.Bacterial V3 V4 region of16 s r DNA from each stool sample were amplified and sequenced.RESULTS The postpartum gut microbiota colonization started to diverge among NEC,LOS and their matched control groups,from the second week after birth.Late-onset sepsis infants held the least diversified gut microbiota(Shannon index=1.66),with the control group held the most diversified one(Shannon index=0.88,p=0.01).The relative abundance of the potential pathogenic genus Enterococcus(20.86%),Staphylococcus(8.67%)and Streptococcus(8.58%)were the highest in NEC patients(p = 0.034),while Klebsiella as the most abundant genus in the LOS group(42.15%,p = 0.023).The control group contained more Lactococcus than the NEC and LOS groups(13.76%,7.98% and 3.66%,respectively,p = 0.028)CONCLUSIONS Post partum colonization pattern of gut microbiome might predispose preterm newborns to necrotizing enterocolitis or late-onset sepsis,in which reduced diversity of the whole microbiota community and potentially pathogenic genus could have played an essential role in disease progression.Still,more studies are needed to identify etiological strains,underlying mechanisms and correspondent microbial patterns.Part Ⅱ.Pediatric Enterocolitis in Association with Intestinal MicrobiotaAIM To compare the similarities and differences of intestinal microbiota in Hirschsprung’s disease(HD),Hirschsprung-associated enterocolitis(HAEC),necrotizing enterocolitis(NEC)and inflammatory bowel disease(IBD).METHODS 24 patients were enrolled,among them four were HAEC patients,seven were HD patients,six were NEC patients,and severn were IBD.A total of58 fecal samples were collected,including 14 HAEC samples,22 HD samples,15 NEC samples,and 7 IBD samples.The bacterial V3 V4 region of the 16 s r RNA gene from each fecal sample was amplified and sequenced;subsequent analysis included: OTU clustering,annotation of each classification level,diversity analysis and multi-level species discriminant analysis.RESULTS The intestinal microbiota from three groups of enterocolitis are similar in diversity and lower than that of children with HD and healthy children of the same age.In addition,the internal composition and abundance of the microbiome(β diversity)are similar among four groups(PC1 = 32.07%,PC2 = 24.84%).From the perspective of taxonomic evolution,the compositions of the gut microbiota of children with enteritis are similar at the phylum level;however,on the genus level,compositional differences were observed: Enterococcus were dominant among the HAEC patients(38.02%,p = 0.01),and it is similar to the HD patients;the abundance of each genus from the IBD patients is roughly equal;the components of intestinal microbiota from the NEC cases are relatively simpler,and Klebsiella is the dominant bacteria.In addition,higher levels of Veillonella(14%,p = 0.02)are seen in the IBD group,which is closely associated with intestinal mucosal epithelial inflammation.CONCLUSIONS Intestinal microecological dysbosis,including reduced diversity and increased abundance of Gram-negative bacteria,might contributes to the certain commonality during the intestinal inflammatory state.This may also be an intrinsic correlative factor of three enteritis with similar clinical manifestations and pathological features.