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Escherichia coli O157:H7 and Shigella flexneri are well-known food-borne pathogens causing severe food poisoning at low infectious doses. Bacteriophages have been approved for food applications by the US Food and Drug Administration (FDA) and have been suggested as natural food preservatives to control specific food-borne pathogens. To develop a novel natural food preservative against E. coli O157:H7 and S. flexneri, a new bacteriophage needs to be isolated and characterized. Bacteriophage HY01 infecting both E. coli O157:H7 and S. flexneri was isolated from a swine fecal sample. HY01 belongs to the family Myoviridae and is stable under various temperature and pH conditions. One-step growth curve analysis showed relatively short eclipse and latent periods as well as large burst size. The 167-kb genome sequence of HY01 was sequenced, and a comparative genome analysis with T4 for non-O157:H7 E. coli suggests that the receptor recognition protein of HY01 plays an important role in determination of host recognition and specificity. In addition, food applications using edible cabbage were conducted with two E. coli O157:H7 strains (ATCC 43890 and ATCC 43895), showing that treatment with HY01 inhibits these clinical and food isolates with >2 log reductions in bacterial load during the first 2 h of incubation. HY01 can inhibit both E. coli O157:H7 and S. flexneri with large burst size and stability under stress conditions. The ability of HY01 to infect both E. coli O157:H7 and S. flexneri may be derived from the presence of two different host specificity-associated tail genes in the genome. Food applications revealed the specific ability of HY01 to inhibit both pathogens in food, suggesting its potential as a novel biocontrol agent or novel natural food preservative against E. coli O157:H7 and potentially S. flexneri.

Salmonella enterica subspecies enterica serovar Typhimurium is a gram-negative pathogen causing salmonellosis. Salmonella Typhimurium-targeting bacteriophages have been proposed as an alternative biocontrol agent to antibiotics. To further understand infection and interaction mechanisms between the host strains and the bacteriophages, the receptor diversity of these phages needs to be elucidated. Twenty-five Salmonella phages were isolated and their receptors were identified by screening a Tn5 random mutant library of S. Typhimurium SL1344. Among them, three types of receptors were identified flagella (11 phages), vitamin B(12) uptake outer membrane protein, BtuB (7 phages) and lipopolysaccharide-related O-antigen (7 phages). TEM observation revealed that the phages using flagella (group F) or BtuB (group B) as a receptor belong to Siphoviridae family, and the phages using O-antigen of LPS as a receptor (group L) belong to Podoviridae family. Interestingly, while some of group F phages (F-I) target FliC host receptor, others (F-II) target both FliC and FljB receptors, suggesting that two subgroups are present in group F phages. Cross-resistance assay of group B and L revealed that group L phages could not infect group B phage-resistant strains and reversely group B phages could not infect group L SPN9TCW-resistant strain. In this report, three receptor groups of 25 newly isolated S. Typhimurium-targeting phages were determined. Among them, two subgroups of group F phages interact with their host receptors in different manner. In addition, the host receptors of group B or group L SPN9TCW phages hinder other group phage infection, probably due to interaction between receptors of their groups. This study provides novel insights into phage-host receptor interaction for Salmonella phages and will inform development of optimal phage therapy for protection against Salmonella.

Background Preventing post-weaning diarrhea (PWD) in weaned piglets is a crucial challenge in the swine production industry. The stress of weaning, dietary shifts from maternal milk to solid feed, and environmental changes lead to decreased microbial diversity, increased pathogen abundance, and compromised intestinal integrity. We have previously identified Lactiplantibacillus argentoratensis AGMB00912 (LA) in healthy porcine feces, which demonstrated antimicrobial activity against pathogens and enhanced short-chain fatty acid production. This research aimed to evaluate the efficacy of LA strain supplementation as a strategy to inhibit PWD and enhance overall growth performance in weaned piglets. Results LA supplementation in weaned piglets significantly increased body weight gain, average daily gain, and average daily feed intake. It also alleviated diarrhea symptoms (diarrhea score and incidence). Notably, LA was found to enrich beneficial microbial populations ( Lactobacillus , Anaerobutyricum , Roseburia , Lachnospiraceae , and Blautia ) while reducing the abundance of harmful bacteria ( Helicobacter and Campylobacter ). This not only reduces the direct impact of pathogens but also improves the overall gut microbiota structure, thus enhancing the resilience of weaned piglets. LA treatment also promotes the growth of the small intestinal epithelial structure, strengthens gut barrier integrity, and increases short-chain fatty acid levels in the gut. Conclusions The study findings demonstrate the promising potential of LA in preventing PWD. Supplementation with the LA strain offers a promising feed additive for improving intestinal health and growth in piglets during the weaning transition, with the potential to significantly reduce the incidence and severity of PWD.

This study aimed to evaluate the efficacy of Lactiplantibacillus argentoratensis AGMB00912 (LA) in reducing Salmonella Typhimurium infection in weaned piglets. The investigation focused on the influence of LA on the gut microbiota composition, growth performance, and Salmonella fecal shedding. The results indicated that LA supplementation significantly improved average daily gain and reduced the prevalence and severity of diarrhea. Fecal analysis revealed reduced Salmonella shedding in the LA-supplemented group. Furthermore, LA notably altered the composition of the gut microbiota, increasing the levels of beneficial Bacillus and decreasing those of harmful Proteobacteria and Spirochaetes. Histopathological examination showed less intestinal damage in LA-treated piglets than in the controls. The study also observed that LA affected metabolic functions related to carbohydrate, amino acid, and fatty acid metabolism, thereby enhancing gut health and resilience against infection. Short-chain fatty acid concentrations in the feces were higher in the LA group, suggesting improved gut microbial activity. LA supplementation enriched the population of beneficial bacteria, including Streptococcus , Clostridium , and Bifidobacterium , while reducing the number of harmful bacteria, such as Escherichia and Campylobacter . These findings indicate the potential of LA as a probiotic alternative for swine nutrition, offering protective effects to the gut microbiota against Salmonella infection.

We investigated microbiota changes following surgical colon cancer resection and evaluate effects of probiotics on microbiota and surgical recovery. This randomized double-blind trial was performed at four medical centers in South Korea. Of 68 patients expected to undergo anterior sigmoid colon cancer resection, 60 were eligible, of whom 29 and 31 received probiotics and placebo, respectively, for four weeks, starting at one week preoperatively. Third- and/or fourth-week information on anterior resection syndrome (ARS), inflammatory markers, and quality of life was obtained. Stool sample analysis was conducted after randomization and bowel preparation and at three and four postoperative weeks. Bacteria were categorized into Set I (with probiotic effects) and II (colon cancer-associated). The probiotic group’s ARS score showed an improving trend (p = 0.063), particularly for flatus control (p = 0.030). Serum zonulin levels significantly decreased with probiotics. Probiotic ingestion resulted in compositional changes in gut microbiota; greater increases and decreases in Set I and II bacteria, respectively, occurred with probiotics. Compositional increase in Set I bacteria was associated with reduced white blood cells, neutrophils, neutrophil-lymphocyte ratio, and zonulin. Bifidobacterium composition was negatively correlated with zonulin levels in the probiotic group. Probiotics improved postoperative flatus control and modified postoperative changes in microbiota and inflammatory markers.

We investigated the potential of Inula britannica extract encapsulated in liposomes as a functional food ingredient with enhanced bioavailability and stability. Inula britannica, known for its anti-inflammatory properties and various health benefits, was encapsulated using a liposome mass production manufacturing method, and the physical properties of liposomes were evaluated. The liposomes exhibited improved anti-inflammatory effects in lipopolysaccharide-activated RAW 264.7 macrophages, suppressing the production of pro-inflammatory mediators such as nitric oxide and prostaglandin E2 and downregulating the expression of iNOS and COX-2 transcription factors. Additionally, we observed reduced production of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, and modulation of the NF-κB and mitogen-activated protein kinase signaling pathways. These findings suggest that Inula britannica extract encapsulated in liposomes could serve as a valuable functional food ingredient for managing and preventing inflammation-related disorders, making it a promising candidate for incorporation into various functional food products. The enhanced absorption and stability provided by liposomal encapsulation can enable better utilization of the extract’s beneficial properties, promoting overall health and well-being.

A novel bacteriophage that infects S. aureus, SA97, was isolated and characterized. The phage SA97 belongs to the Siphoviridae family, and the cell wall teichoic acid (WTA) was found to be a host receptor of the phage SA97. Genome analysis revealed that SA97 contains 40,592 bp of DNA encoding 54 predicted open reading frames (ORFs), and none of these genes were related to virulence or drug resistance. Although a few genes associated with lysogen formation were detected in the phage SA97 genome, the phage SA97 produced neither lysogen nor transductant in S. aureus. These results suggest that the phage SA97 may be a promising candidate for controlling S. aureus.

Klebsiella is a genus of well-known opportunistic human pathogens that are associated with diabetes mellitus and chronic pulmonary obstruction; however, this pathogen is often resistant to multiple drugs. To control this pathogen, two Klebsiella -infecting phages, K. oxytoca phage PKO111 and K. pneumoniae phage PKP126, were isolated from a sewage sample. Analysis of their host range revealed that they infect K. pneumoniae and K. oxytoca , suggesting host specificity for members of the genus Klebsiella . Stability tests confirmed that the phages are stable under various temperature (4 to 60 °C) and pH (3 to 11) conditions. A challenge assay showed that PKO111 and PKP126 inhibit growth of their host strains by 2 log and 4 log, respectively. Complete genome sequencing of the phages revealed that their genome sizes are quite different (168,758 bp for PKO111 and 50,934 bp for PKP126). Their genome annotation results showed that they have no human virulence-related genes, an important safety consideration. In addition, no lysogen-formation gene cluster was detected in either phage genome, suggesting that they are both virulent phages in their bacterial hosts. Based on these results, PKO111 and PKP126 may be good candidates for development of biocontrol agents against members of the genus Klebsiella for therapeutic purposes. A comparative analysis of tail-associated gene clusters of PKO111 and PKP126 revealed relatively low homology, suggesting that they might differ in the way they recognize and infect their specific hosts.

A novel, strictly anaerobic, gram-negative, segmented filamentous bacterium strain AGMB03513T, was isolated from the faeces of a 5-month-old pig. Phylogenetic analysis based on the 16S rRNA gene indicated that the isolate was a member of the family Lachnospiraceae, and the closest strain was Anaerostipes butyraticus. Strain AGMB03513T formed a lineage within the genus Anaerostipes and was closely related to A. butyraticus DSM 22094 T (= KCTC 15125 T, 95.8%), Anaerostipes hadrus DSM 3319 T (= KCTC 15606 T, 95.5%), Anaerostipes caccae DSM 14662 T (= KCTC 15019 T, 94.0%), and Anaerostipes rhamnosivorans DSM 26241 T (= KCTC 15316 T, 93.4%). Strain AGMB03513T grew at temperatures between 30 and 45 °C, within a pH range of 7.0–9.0, and in medium containing up to 1.5% NaCl. Cells were found to utilise d-glucose, d-mannitol, d-lactose, d-saccharose, d-maltose, d-xylose, l-arabinose, d-mannose, and d-sorbitol, and acetate was identified as the major end product of metabolism. The major components of the cellular fatty acids were C12:0, C16:0, and C18:0. In addition, the bacterium contained meso-diaminopimelic acid in the cell wall. According to the comparative analysis of the whole genome sequence, the DNA G + C content of strain AGMB03513 was 37.0 mol%. In addition, Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridisation (dDDH) values were obtained in comparisons of strain AGMB03513T with reference strains of species in the genus Anaerostipes. ANI values were found to be between 71.0 and 75.7%, AAI values between 66.6 and 73.2%, and dDDH values between 19.5 and 21.4%. All the data were below the threshold range for species determination. Based on phenotypic, phylogenetic, biochemical, chemotaxonomic, and genomic characteristics, we considered it reasonable to assign a novel species status to strain AGMB03513T, for which we propose the name Anaerostipes faecalis sp. nov. The type strain is AGMB03513T (= KCTC 25020 T = NBRC 114896 T).

An obligately anaerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped strain AGMB00832T was isolated from swine faeces. Phylogenetic analysis based on the 16S rRNA gene, together with the housekeeping genes, gyrB and rpoD, revealed that strain AGMB00832T belonged to the genus Faecalicatena and was most closely related to Faecalicatena orotica KCTC 15331T. In biochemical analysis, strain AGMB00832T was shown to be negative for catalase, oxidase and urease. Furthermore, the isolate was positive for β-glucosidase, β-glucuronidase, glutamic acid decarboxylase, proline arylamidase, acid phosphatase and naphthol-AS-BI-phosphohydrolase. The major cellular fatty acids (> 10%) of the isolate were C14:0, C16:0 and C18:1ω11t DMA. Based on the whole genome sequence analysis, the DNA G + C content of strain AGMB00832T was 44.2 mol%, and the genome size and numbers of rRNA and tRNA genes were 5,175,159 bp, 11 and 53, respectively. The average nucleotide identity and digital DNA–DNA hybridization values between strain AGMB00832T and related strains were ≤ 77.4 and 22.5%, respectively. Furthermore, the genome analysis revealed the presence of genes for alkaline shock protein 23 and cation/proton antiporters, which may facilitate growth of strain AGMB00832T in alkaline culture condition. On the basis of polyphasic taxonomic approach, strain AGMB00832T represents a novel species within the genus Faecalicatena, for which the name Faecalicatena faecalis sp. nov. is proposed. The type strain is AGMB00832T (= KCTC 15946T = NBRC 114613T).