Butyrate Producers in Very Low Birth Weight Infants with Neither Culture-Proven Sepsis nor Necrotizing Enterocolitis

<b>Background/Objectives</b>: Severe infection (sInfection; either late-onset culture-proven sepsis or necrotizing enterocolitis) in very low birth weight (VLBW) infants increases mortality rates and may show long-term progression. The fecal microbiome composition in VLBW infants with and without sInfection was classified in the sInfection and non-sInfection groups. <b>Methods</b>: Gut microbiomes, secondary information from a previous randomized trial, were analyzed using QIIME 2 software. The biodiversity and abundance of the gut microbiota between the sInfection and non-sInfection groups were compared. <b>Results</b>: Fifty-one neonates were included in the sInfection (<i>n</i> = 9) and non-sInfection (<i>n</i> = 42) groups; no significant differences in the fecal microbiome were observed in both alpha and beta diversities. Analysis of relative abundance revealed that in both groups, the predominant gut microbiota phylum, class, and genus were Proteobacteria, Gammaproteobacteria, and <i>Klebsiella</i>, respectively. The main fecal microbiome in the non-sInfection group included <i>Faecalibacterium</i>, <i>Clostridium butyricum</i>, and <i>Bacteroides fragilis</i>. <i>Clostridium_sensu_stricto _1</i> was significantly more abundant in the non-sInfection group than in the sInfection group. <b>Conclusions</b>: <i>Clostridium_sensu_stricto_1</i> was the main gut microbiota in the non-sInfection group. Considering the potential taxa as synbiotics (correlations among prebiotics, probiotics, and postbiotics), therapeutics may be useful for preventing and managing necrotizing enterocolitis or late-onset culture-proven sepsis in VLBW infants.