Background: The production of intestinal gases and fecal short-chain fatty acids (SCFAs) by infant gut microbiota may have a significant impact on their health, but information about the composition and volume of intestinal gases and SCFA profiles in preterm infants is scarce.Objective: This study examined the change of the composition and volume of intestinal gases and SCFA profiles produced by preterm infant gut microbiota in vitro during the first 4 weeks of life.Methods: Fecal samples were obtained at five time points (within 3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks) from 19 preterm infants hospitalized in the neonatal intensive care unit (NICU) of Shanghai Children's Hospital, Shanghai Jiao Tong University between May and July 2020. These samples were initially inoculated into four different media containing lactose (LAT), fructooligosaccharide (FOS), 2′-fucosyllactose (FL-2), and galactooligosaccharide (GOS) and thereafter fermented for 24 h under conditions mimicking those of the large intestine at 37.8°C under anaerobic conditions. The volume of total intestinal gases and the concentrations of individual carbon dioxide (CO2), hydrogen (H2), methane (CH4), and hydrogen sulfide (H2S) were measured by a gas analyzer. The concentrations of total SCFAs, individual acetic acid, propanoic acid, butyric acid, isobutyric acid, pentanoic acid, and valeric acid were measured by gas chromatography (GC).Results: The total volume of intestinal gases (ranging from 0.01 to 1.64 ml in medium with LAT; 0–1.42 ml with GOS; 0–0.91 ml with FOS; and 0–0.44 ml with FL-2) and the concentrations of CO2, H2, H2S, and all six fecal SCFAs increased with age (p-trends < 0.05). Among them, CO2 was usually the predominant intestinal gas, and acetic acid was usually the predominant SCFA. When stratified by birth weight (<1,500 and ≥1,500 g), gender, and delivery mode, the concentration of CO2 was more pronounced among infants whose weight was ≥1,500 g than among those whose weight was <1,500 g (p-trends < 0.05).Conclusions: Our findings suggested that the intestinal gases and SCFAs produced by preterm infant gut microbiota in vitro increased with age during the first 4 weeks of life.

Objective: This study aims to explore whether there was a correlation between unexplained severe neonatal hyperbilirubinemia and the following six gene pathogenic variants: c.211G>A of UGT1A1 gene, c.388A>G, c.597C>T, c.521T>C of SLCO1B1 gene, c.175T>C, and c.7G>A of BLVRA gene.Methods: This was a case-control study. The hyperbilirubinemia group, including 65 neonates with unexplained severe hyperbilirubinemia (serum total bilirubin level ≥342 μmol·L-1), was hospitalized in the neonatal intensive care unit of Shanghai Children's Hospital from January 2019 to September 2020. The control group included 52 neonates with birth defects and serum total bilirubin level £221 μmol·L-1. The six gene pathogenic variants mentioned above were investigated using MLPA-NGS technique. Pathogenic variants and allele frequencies were compared between the two groups.Results: Compared with previous sequencing results, the concordance rate of c.211G>A was 98.3% (115/117), while all other pathogenic variants had a concordance rate of 100%. The pathogenic variants frequencies were as follows: c.388A>G of SLCO1B1 gene (93.84%)>c.7G>A of BLVRA gene (89.23%)> c.597C>T of SLCO1B1 gene (81.54%)> c.211G>A of UGT1A1 gene (69.23%)> c.521T>C of SLCO1B1 gene (26.15%)> c.175T>C of BLVRA gene (18.46%). A allele frequency of c.211G>A of hyperbilirubinemia group was 45.38%, while A allele frequency of control group was 21.15%. The differences were statistically significant, with c2=14.988, P<0.001. No significant difference was observed in allele frequency of other gene pathogenic variants between the two groups, with P>0.05. Binary logistic regression results revealed that c.211G>A of UGT1A1 gene was a high-risk factor for unexplained severe neonatal hyperbilirubinemia, with OR=4.233, 95% CI: 1.896-9.451. No significant difference was observed in serum total bilirubin levels between mutation types.Conclusions: c.211G>A of UGT1A1 gene was significantly correlated with unexplained severe neonatal hyperbilirubinemia and was a high-risk factor for the disease. MLPA-NGS technique was a highly accurate, rapid, and cost-effective method in identifying common and known gene loci of severe neonatal hyperbilirubinemia. It can be employed as a point mutation screening approach for detecting hyperbilirubinemia-related pathogenic variants.