The imbalance of gut microbiota is known to be associated with inflammatory bowel disease, but it remains unknown whether dysbiosis is a cause or consequence of chronic gut inflammation. In order to investigate the effects of gut inflammation on microbiota and metabolome, the sequential changes in gut microbiota and metabolites from the onset of colitis to the recovery in dextran sulfate sodium-induced colitic mice were characterized by using meta 16S rRNA sequencing and proton nuclear magnetic resonance (¹H-NMR) analysis. Mice in the colitis progression phase showed the transient expansions of two bacterial families including Bacteroidaceae and Enterobacteriaceae and the depletion of major gut commensal bacteria belonging to the uncultured Bacteroidales family S24-7, Rikenellaceae, Lachnospiraceae, and Ruminococcaceae. After the initiation of the recovery, commensal Lactobacillus members promptly predominated in gut while other normally abundant bacteria excluding the Erysipelotrichaceae remained diminished. Furthermore, ¹H-NMR analysis revealed characteristic fluctuations in fecal levels of organic acids (lactate and succinate) associated with the disease states. In conclusion, acute intestinal inflammation is a perturbation factor of gut microbiota but alters the intestinal environments suitable for Lactobacillus members.

Background: Bacteriophage (phage) therapy has regained attention as an alternative to antimicrobial agents for eliminating bacteria; however, the emergence of phage-resistant bacteria during the therapy is a major concern. One method to control this emergence is to create a cocktail composed of multiple phages. Materials and Methods: In this study, we isolated 28 phages infecting Escherichia coli and evaluated their bacteriolysis (lysis) activity, lytic spectrum, adsorption rate constant, burst size, and titer of a 1-day incubation, followed by clustering of the phages based on these physiological characteristics. Results: The variation in lysis onset time and duration was more significant for cocktails of phages from different clusters than for phage cocktails from the same cluster. Conclusions: This suggests that a combination of phages with different physiological characteristics is necessary to create a cocktail that rapidly and continuously lyses bacteria over a prolonged duration while suppressing the emergence of resistant bacterial strains.

Severe cases of COVID-19 continue to put pressure on medical operations by prolonging hospitalization, occupying intensive care beds, and forcing medical personnel to undergo harsh labor. The eradication of SARS-CoV-2 through vaccine development has yet to be achieved, mainly due to the appearance of multiple mutant-incorporating strains. The present study explored the utility of human intravenous immunoglobulin (IVIG) preparations in suppressing the aggravation of any COVID-19 infection using a SARS-CoV-2 pseudovirus assay. Our study revealed the existence of IgG antibodies in human IVIG preparations, which recognized the spike protein of SARS-CoV-2. Remarkably, the pretreatment of ACE2/TMPRSS2-expressing host cells (HEK293T cells) with IVIG preparations (10 mg/mL) inhibited approximately 40% entry of SARS-CoV-2 pseudovirus even at extremely low concentrations of IgG (0.16–1.25 mg/mL). In contrast, the antibody-dependent enhancement of viral entry was confirmed when SARS-CoV-2 pseudovirus was treated with some products at an IgG concentration of 10 mg/mL. Our data suggest that IVIG may contribute to therapy for COVID-19, including for cases caused by SARS-CoV-2 variants, since IVIG binds not only to the spike proteins of the virus, but also to human ACE2/TMPRSS2. An even better preventive effect can be expected with blood collected after the start of the COVID-19 pandemic.

Bacteriophages play crucial roles in microbial ecosystems and have potential for biotechnological applications. However, our understanding of culturable phages remains limited. In this study, we characterized six novel Escherichia coli phages isolated from pig farm wastewater and urban sewage, using comprehensive genomic, morphological, and host-range analysis. Using multiple comparative approaches, including gene-sharing network analysis, average nucleotide identity (ANI), and nucleotide intergenomic similarity (NIS), we demonstrated that five of these phages form a distinct group within the subfamily Stephanstirmvirinae , potentially representing a novel genus, for which we propose the name " Wecvirus ”. We further propose that these phages, each of which exhibits a unique host range pattern, should be classified in two distinct species within the proposed genus. This host specificity is reflected in differences in the amino acid sequences of tail fibers, which are crucial for infection. The remaining phage, which was not classified as a wecvirus, exhibited characteristics that challenged the current classification criteria, highlighting the need for more-flexible taxonomic approaches. These findings expand our understanding of phage diversity within the subfamily Stephanstirmvirinae and contribute to the evolving phage taxonomy framework.

Bacteriophages play crucial roles in microbial ecosystems and have potential biotechnological applications. However, our understanding of culturable phages remains limited. This study characterized six novel Escherichia coli phages isolated from pig farm wastewater and urban sewage using comprehensive genomic, morphological, and host-range analyses. Using multiple comparative approaches, including gene-sharing network analysis, average nucleotide identity (ANI), and nucleotide intergenomic similarity (NIS), we demonstrated that five of these phages form a distinct group within the subfamily Stephanstirmvirinae , potentially representing a novel genus provisionally named " Wecvirus ”. These phages were further classified into two distinct species within the proposed genus, each of which exhibits a unique host range pattern. This host specificity is reflected in the species-specific differences in the amino acid sequences of tail fibers, which are crucial for infection. The remaining phage, which was not classified as Wecvirus exhibited characteristics that challenged the current classification criteria, highlighting the need for more flexible taxonomic approaches. Our findings expand the understanding of phage diversity within Stephanstirmvirinae and contribute to the evolving phage taxonomy framework. Importance: The rapid emergence of antibiotic-resistant pathogens necessitates the development of alternative antimicrobial strategies, with phage therapy showing promising potential. However, the successful implementation of phage-based treatments requires a comprehensive understanding of phage diversity and host-pathogen interactions. Our study expands the known diversity within Stephanstirmvirinae by characterizing novel E. coli phages that constitute a distinct genus. The identification of species-specific host recognition mechanisms within this genus provides insights into phage-host adaptation. These findings contribute to our understanding of phage taxonomy and evolution, while also offering practical implications for the development of phage-based therapeutics against pathogenic E. coli strains. This research highlights the importance of continued exploration of novel phages for both fundamental understanding and therapeutic applications.