A novel phage specific for Klebsiella pneumoniae, named vB_KpnS_2146 - 302, was isolated from hospital wastewater. Through transmission electron microscopy observation and genomic analysis, this phage was found to belong to the genus Webervirus in the family Drexlerviridae. Biological studies showed that vB_KpnS_2146 - 302 has a narrow host range and exhibits specific lytic activity against K. pneumoniae. A one-step growth curve showed a latency period of 10 minutes and a burst size of 1125 PFU/cell. The phage remained stable within a pH range of 3-9 and a temperature range of 26-60°C. Whole-genome sequencing analysis showed that the double-stranded DNA genome of vB_KpnS_2146 - 302 is 50,299 bp in length and contains 76 open reading frames. Experiments in which cells were treated with proteinase K or periodate suggested that the carbohydrate structure of K. pneumoniae is involved in the adsorption of this phage. This study shows that phage vB_KpnS_2146 - 302 might be a new candidate for the development of phage therapy against K. pneumoniae infections.

A causal relationship between changes of the gut microbiome and non-alcoholic fatty liver disease (NAFLD) remains unclear. We demonstrated that endogenous ethanol (EnEth) produced by intestinal microbiota is likely a causative agent of NAFLD.

Galacto-oligosaccharides (GOS) are prebiotics that positively affect the host's gut microbiota, which is important for the health of the host. Most previous studies focused on specific flora components (e.g. Bifidobacterium and Lactobacillus); very few have investigated the relationship between flora and metabolites. Here, we used 16S rRNA analysis and metabolomics to analyze the effect of GOS on microbiota and metabolites. Results show that the abundance of Ruminococcaceae and Oscillibacter decreased significantly in GOS-fed mice. Twenty-one metabolites, including oleic acid, arachidic acid, and behenic acid, decreased significantly in the GOS-fed mice. Fatty acid synthesis and blood triglyceride content significantly decreased in the GOS-fed mice compared with those in the control mice, suggesting that GOS may improve lipid metabolism in mice. Additionally, after three weeks of a GOS-rich diet, the mouse microbiota was significantly enriched in Alloprevotella, Bacteroides, and Parasutterella. The blood glucose level of the GOS-fed group was significantly higher than that of the control group, whereas the abundance of Coprococcus and Odoribacter (butyrate-producing bacteria) was significantly decreased. The metabolism of butyrate, known to reduce plasma glucose levels, was significantly downregulated in the GOS-fed mice, an effect potentially detrimental to the glucose metabolism of the host. This dual-omics analysis provided important information on the changes in host-microbe-metabolite interactions resulting from GOS supplementation. Our results provide evidence that GOS may improve lipid metabolism, and that long-term GOS supplementation had a detrimental effect on the host's glucose metabolism, which could be important for optimizing methods of prebiotic supplementation and developing approaches to prevent diseases using prebiotic interventions.

is an important nosocomial infectious bacterium, more and more multidrug resistant have been isolated and posed severe challenges to clinical antibiotic treatment, bringing additional morbidity, mortality, and economic burden. Bacteriophages can lyse bacteria specificity and are feasible alternatives to antibiotics.