Highlights d High-alcohol-producing strains of Klebsiella pneumoniae exist in humans d HiAlc Kpn is associated with NAFLD in a human cohort d Transplant of HiAlc Kpn into mice causes NAFLD d Feeding mice glucose led to detectable blood alcohol, suggesting a biomarker for NAFLD

In the originally published version of this article, the ultra-high blood alcohol concentration was mistakenly given as 400 mg/L instead of 400 mg/dL. The correction has now been made online. This error does not affect the conclusions of the paper. The authors apologize for any confusion that this error may have caused.

Scope: High-salt diets (HSDs) are widely considered to cause health problems such as gut microecological imbalances, constipation, and hypertension. This study explores how lactulose as a safe molecule can stimulate bodily responses to alleviate salt-sensitive hypertension by regulating the gut microbiotas of HSD-fed mice. Methods and results: After 4 weeks, the blood pressures of mice fed a high-salt plus lactulose diet (HSLD) are significantly lower than those of the HSD-fed mice. The HSD increases the abundances of Alistipes and Ruminococcaceae UCG 009 and reduced the abundance of Lactobacillus in the gut, while lactulose supplementation increases the abundances of Bifidobacterium, Alloprevotella, and Subdoligranulum. Fecal metabolic profiling shows significant increases in metabolites involved in ATP-binding cassette transporter pathways, and tryptophan metabolism is significantly reduced in the HSLD group compared with the HSD group. Lactulose maintains the intestinal microenvironmental health in the HSD-fed mice by improving glycolipid metabolism, decreasing the small intestinal interleukin-17a (IL-17a) and interleukin-22 (IL-22) mRNA levels and serum IL-17a and IL-22 levels, relieving constipation, increasing fecal sodium, and reducing intestinal permeability. Conclusion: Lactulose negates salt-sensitive hypertension. Regulating the gut microbiota is a potential treatment for salt-sensitive hypertension.

Carbapenem-resistant Enterobacter aerogenes strains are a major clinical problem because of the lack of effective alternative antibiotics. However, viruses that lyze bacteria, called bacteriophages, have potential therapeutic applications in the control of antibiotic-resistant bacteria. In the present study, a lytic bacteriophage specific for E. aerogenes isolates, designated vB_EaeM_φEap-3, was characterized. Based on transmission electron microscopy analysis, phage vB_EaeM_φEap-3 was classified as a member of the family Myoviridae (order, Caudovirales). Host range determination revealed that vB_EaeM_φEap-3 lyzed 18 of the 28 E. aerogenes strains tested, while a one-step growth curve showed a short latent period and a moderate burst size. The stability of vB_EaeM_φEap-3 at various temperatures and pH levels was also examined. Genomic sequencing and bioinformatics analysis revealed that vB_EaeM_φEap-3 has a 175,814-bp double-stranded DNA genome that does not contain any genes considered undesirable for the development of therapeutics (e.g., antibiotic resistance genes, toxin-encoding genes, integrase). The phage genome contained 278 putative protein-coding genes and one tRNA gene, tRNA-Met (AUG). Phylogenetic analysis based on large terminase subunit and major capsid protein sequences suggested that vB_EaeM_φEap-3 belongs to novel genus “Kp15 virus” within the T4-like virus subfamily. Based on host range, genomic, and physiological parameters, we propose that phage vB_EaeM_φEap-3 is a suitable candidate for phage therapy applications.

Lactulose, a safe and beneficial molecule, can be used in food as a prebiotic and as an osmotic laxative during pregnancy. This work evaluated the effects of dietary lactulose on the gut microenvironment of pregnant mice using the fecal microbiota and metabolomic profiling. After 2 weeks of feeding, the Bifidobacterium and Bacteroides abundances in the mouse feces were significantly increased in the LAC-high (the diet supplemented with 15% lactulose) group. A total of 15 metabolites, including 1-monoolein, glucose-6-phosphate, and short-chain fatty acids, were increased significantly in the LAC-high group. The serum glucose and total cholesterol concentrations were significantly decreased, while the progesterone level was significantly increased in the lactulose-fed mice. In the LAC-high group, the colonic pH and intestinal permeability were decreased, while the immunoglobulins in the colonic epithelial cells and the small intestinal absorption capacity were significantly increased. These findings indicated that lactulose supplementation benefitted pregnancy performance in mice.

No abstract

Achromobacter phage phiAxp-3, an N4-like bacteriophage, specifically recognize Achromobacter xylosoxidans lipopolysaccharide (LPS) as its receptor. PhiAxp-3 tail sheath protein (TSP, ORF69) shares 54% amino acid sequence identity with the TSP of phage N4 (gp65); the latter functions as a receptor binding protein and interacts with the outer membrane receptor NfrA of its host bacterium. Thus, we hypothesized that ORF69 is the receptor-binding protein of phiAxp-3. In the present study, a series of ORF69 truncation variants was constructed to identify the part(s) of this protein essential for binding to A. xylosoxidans LPS. Phage adsorption and enzyme-linked immunosorbent assay showed that amino acids 795–1195 of the TSP, i.e., ORF69(795–1195), are sufficient and essential for receptor and binding. The optimum temperature and pH for the functions of ORF69 and ORF69(795–1195) are 4/25°C and 7, respectively. In vitro cytotoxicity assays showed that ORF69 and ORF69(795–1195) were respectively toxic and non-toxic to a human immortalized normal hepatocyte cell line (LO2; doses: 0.375–12 μg). The potential of this non-toxic truncated version of phiASP-3 TSP for clinical applications is discussed.

27Non-alcoholic fatty liver disease (NAFLD), a prelude of cirrhosis and hepatocellular carcinoma, is the 28 most common chronic liver disease worldwide. NAFLD has been considerated to be associated with 29 the composition of gut microbiota. However, causal relationship between change of gut microbiome 30 and NAFLD remains unclear. Here we show that Klebsiella pneumoniae was significantly associated 31 with NAFLD through inducing generation of endogenous ethanol. A strain of high alcohol-producing 32Klebsiella pneumoniae (HiAlc Kpn) was initially isolated from fecal samples of patient with 33 non-alcoholic steatohepatitis (NASH) accompanied with auto-brewery syndrome (ABS). Gavage of 34HiAlc Kpn was capable of inducing murine model of fatty liver disease (FLD) in which had typical 35 pathological changes of hepatic steatosis and similar liver gene expression profiles to those of alcohol 36 intake in mice. Data derived from germ-free mice by gnotobiotic gavage further demonstrated that the 37 HiAlc Kpn is the major cause of the changes in FLD mice. Furthermore, using proteomic and 38 metabolitic analysis, we found that HiAlc Kpn induced generation of endogenous alcohol through the 39 2,3-butanediol fermentation pathway. More interestingly, the blood alcohol concentration was elevated 40 in FLD mice induced by HiAlc Kpn after glucose intake. Clinical analysis showed that HiAlc Kpn 41 were observed in up to 60% of patients with NAFLD. Our results suggested that HiAlc Kpn make 42 important contribution to NAFLD, possibly through generation of the endogenous alcohol. Thus, 43 targeting these bacteria might provide a novel therapeutic for clinical treatment of NAFLD. 44 45 Key words: Fatty liver disease, alcohol-producing bacteria, gut microbiota, Klebsiella pneumonia, 46Endo-AFLD 47 3 the disease normally are initiated with fat deposition in liver and followed with liver injury, including 54 steatohepatitis, inflammation, fibrosis, cirrhosis and hepatocellular carcinoma 4,5 . The major cause of 55 the AFLD is alcohol intake, while that of the NAFLD remains unclear. Increased evidence has shown 56 that NAFLD is strongly associated with obesity, the metabolic/insulin resistance syndrome, 57 dyslipidemia 6-8 and alterations of gut microbiota 9 . 58Alterations of constitutional microbiota, such as Firmicutes, Bacteroidetes, Actinobacteria, and 59Proteobacteria, might impair the basic in vivo functions including the immune system, the 60 maintenance of nutrition, xenobiotics metabolism, development and proliferation of intestinal cells, 61 and protection against aggressor microorganisms. Metagenomic analyses revealed that the metabolic 62 diseases such as obesity 10-13 , the metabolic syndromes 14 , non-alcoholic steatohepatitis (NASH) and 63 cirrhosis 9 are the results of disorder of the composition of gut microbiota. Particularly, it has been 64 shown that the enrichment of Eubacterium rectale, E. rectale, Bacteroides vulgates and etc. correlates 65 with NAFLD, possibly through effecting of harmful metabolic mediators on ...