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Frontiers in Microbiology 2024Probiotic bacteria have been proposed as an alternative to antibiotics for the control of antimicrobial resistant enteric pathogens. The mechanistic details of this...
Probiotic bacteria have been proposed as an alternative to antibiotics for the control of antimicrobial resistant enteric pathogens. The mechanistic details of this approach remain unclear, in part because pathogen reduction appears to be both strain and ecology dependent. Here we tested the ability of five probiotic strains, including some from common probiotic genera and , to reduce binding of sv. Typhimurium to epithelial cells subsp. emerged as a promising strain; however, Typhimurium infection outcome in epithelial cells was dependent on inoculation order, with unable to rescue host cells from preceding or concurrent infection. We further investigated the complex mechanisms underlying this interaction between , Typhimurium, and epithelial cells using a multi-omics approach that included gene expression and altered metabolism via metabolomics. Incubation with repressed apoptotic pathways and induced anti-inflammatory cascades in epithelial cells. In contrast, co-incubation with increased in Typhimurium the expression of virulence factors, induced anaerobic metabolism, and repressed components of arginine metabolism as well as altering the metabolic profile. Concurrent application of the probiotic and pathogen notably generated metabolic profiles more similar to that of the probiotic alone than to the pathogen, indicating a central role for metabolism in modulating probiotic-pathogen-host interactions. Together these data imply crosstalk via small molecules between the epithelial cells, pathogen and probiotic that consistently demonstrated unique molecular mechanisms specific probiotic/pathogen the individual associations.
PubMed: 38812689
DOI: 10.3389/fmicb.2024.1387498 -
Frontiers in Microbiology 2024is a bacterium that can cause food-borne infections and is responsible for the most common gastrointestinal illnesses. The emergence of multi-drug resistant (MDR)...
INTRODUCTION
is a bacterium that can cause food-borne infections and is responsible for the most common gastrointestinal illnesses. The emergence of multi-drug resistant (MDR) strains worldwide is a major threat, representing a major challenge in public health. To reduce its incidence, the One Health approach is required, and the development of new biocontrol protocols will help prevent or eliminate the spread of . Prevention measures, such as on-farm cleaning and disinfection protocols, are a crucial step in reducing infection to new flocks and eliminating bacteria that remain in the facilities. However, MDR species, such as . Infantis, are highly resistant to conventional cleaning and disinfection protocols, with an increased ability to persist in the broiler farm environment. The need for alternative biocontrol methods has led to the use of bacteriophages or phages, viruses that target bacteria, as promising tools. Thus, the aim of this study was to evaluate the efficacy of phages as a biocide against . Infantis isolates in combination with cleaning and disinfection protocols in 10 commercial poultry farms.
METHODS
All commercial farms selected in this study had persistent , even after the routinely used cleaning and disinfection procedures. In addition, isolated before treatment were phenotypically characterized by antimicrobial resistance patterns.
RESULTS
The results showed that 100% of . Infantis were resistant to at least one antibiotic, and > 70% were MDR. Phages were then isolated against the in-farm bacteria, purified, and multiplied for each poultry farm. The cleaning and disinfection protocols included the application of the lytic phages (vB_Si_CECAV_FGS009; vB_Si_CECAV_FGS017; vB_Si_CECAV_FGS029 and vB_Si_CECAV _FGS030) twice at 24-h intervals between cleaning and disinfection. Following the cleaning and disinfection procedures, detection was reduced from 100% after cleaning to 36% after applying the phages and dropped to 0% after the final step of disinfection, thus eliminating from the farm facilities.
DISCUSSION
This study demonstrates that bacteriophage application after cleaning and before disinfection enhances the removal of MDR Infantis in commercial broiler farms, suggesting their use as biocontrol agents to reduce , a major public health concern.
PubMed: 38812676
DOI: 10.3389/fmicb.2024.1401479 -
Scientific Reports May 2024Salmonella is a primary enteric pathogen related to the contamination of poultry and other food products in numerous foodborne outbreaks. The continuous emergence of...
Salmonella is a primary enteric pathogen related to the contamination of poultry and other food products in numerous foodborne outbreaks. The continuous emergence of multidrug-resistant bacteria has become a serious issue due to the overuse of antibiotics. Hence, lytic phages are considered alternative biocontrol agents against these bacterial superbugs. Here, two Salmonella phages-S4lw and D5lw-were subjected to genomic and biological characterization and further encapsulated to improve the stability under acidic conditions mimicking gastrointestinal conditions. The two lytic phages, S4lw and D5lw, taxonomically belong to new species under the Guernseyvirinae and Ackermannviridae families, respectively. Each phage showed antimicrobial activities against diverse Salmonella spp., such as S. Enteritidis and S. Typhimurium, achieving 1.7-3.4 log reduction after 2-6 h of treatment. The phage cocktail at a multiplicity of infection (MOI) of 100 or 1000 completely inhibited these Salmonella strains for at least 14 h at 25 °C. Additionally, the bead-encapsulated phage cocktail could withstand low pH and different simulated gut environments for at least 1 h. Overall, the newly isolated phages can potentially mitigate Salmonella spp. under the gastrointestinal environments through encapsulation and may be further applied via oral administration to resolve common antimicrobial resistance issues in the poultry production chain.
Topics: Salmonella Phages; Salmonella; Animals; Genome, Viral; Gastrointestinal Tract; Biological Control Agents; Hydrogen-Ion Concentration
PubMed: 38811648
DOI: 10.1038/s41598-024-59502-9 -
Microbiology Resource Announcements May 2024A subgroup of Salmonella (S.) enterica subsp. enterica serovar Paratyphi B is significantly associated with invasive infections in humans. We report the complete genome...
A subgroup of Salmonella (S.) enterica subsp. enterica serovar Paratyphi B is significantly associated with invasive infections in humans. We report the complete genome sequence of a potentially invasive. Paratyphi B isolated from a mute swan () found dead at an urban recreation park in Berlin, Germany.
PubMed: 38809039
DOI: 10.1128/mra.01056-23 -
Virulence Dec 2024subspecies serovar Typhimurium is an intracellular pathogen that invades and colonizes the intestinal epithelium. Following bacterial invasion, is enclosed within a...
subspecies serovar Typhimurium is an intracellular pathogen that invades and colonizes the intestinal epithelium. Following bacterial invasion, is enclosed within a membrane-bound vacuole known as a -containing vacuole (SCV). However, a subset of has the capability to prematurely rupture the SCV and escape, resulting in hyper-replication within the cytosol of epithelial cells. A recently published RNA-seq study provides an overview of cytosolic and vacuolar upregulated genes and highlights vacuolar upregulation. Here, using transcription kinetics, protein production profile, and immunofluorescence microscopy, we showed that PagN is exclusively produced by in SCV. Gentamicin protection and chloroquine resistance assays were performed to demonstrate that deletion of affects replication by affecting the cytosolic bacterial population. This study presents the first example of a virulence factor expressed within the endocytic compartment, which has a significant impact on the dynamics of cytosolic hyper-replication.
Topics: Salmonella typhimurium; Cytosol; Vacuoles; Bacterial Proteins; Virulence Factors; Humans; Virulence; Salmonella Infections; HeLa Cells; Epithelial Cells; Gene Expression Regulation, Bacterial
PubMed: 38804638
DOI: 10.1080/21505594.2024.2357670 -
IJID Regions Jun 2024, a zoonotic pathogen, significantly impacts global human health. Understanding its serotype distribution and antimicrobial resistance is crucial for effective control...
OBJECTIVES
, a zoonotic pathogen, significantly impacts global human health. Understanding its serotype distribution and antimicrobial resistance is crucial for effective control measures and medical interventions.
METHODS
We collected isolates and demographic data from Taiwanese hospitals between 2004 and 2022, analyzing their serotypes and antimicrobial susceptibility.
RESULTS
Among 40,595 isolates, salmonellosis predominated in children aged 0-4 (61.2%) years and among males (55.2%). Males also showed higher rates of extraintestinal infections (18.1% vs 16.0%, <0.001), particularly, in the ≥65 years age group (52.4%). The top five serovars were Enteritidis (32.8%), Typhimurium (21.7%), Newport (6.2%), Stanley (4.7%), and Anatum (4.0%). Notably, . Enteritidis prevalence increased from 23.9% (2004-2005) to 43.6% (2021-2022). Antimicrobial resistance was high, with a 51.6% multidrug resistance (MDR) rate. Disturbingly, MDR rates exceeded 90% in serovars Albany, Schwarzengrund, Choleraesuis, and Goldcoast. Resistance to key therapeutic agents, azithromycin, cefotaxime, and ciprofloxacin, exhibited concerning upward trends, and the surge in cefotaxime and ciprofloxacin resistance was closely linked to the emergence and spread of MDR Anatum and Goldcoast clones.
CONCLUSIONS
Prioritizing control measures against . Enteritidis and closely monitoring the prevalence and spread of MDR clones are imperative to mitigate infections in Taiwan.
PubMed: 38799797
DOI: 10.1016/j.ijregi.2024.100372 -
IScience Jun 2024As therapies, oncolytic viruses regress tumors and have the potential to induce antitumor immune responses that clear hard-to-treat and late-stage cancers. Despite this...
As therapies, oncolytic viruses regress tumors and have the potential to induce antitumor immune responses that clear hard-to-treat and late-stage cancers. Despite this promise, clearance from the blood prevents treatment of internal solid tumors. To address this issue, we developed virus-delivering Salmonella (VDS) to carry oncolytic viruses into cancer cells. The VDS strain contains the delivery circuit and has deletions in four homologous recombination genes (Δ, Δs, Δ, and Δ) to preserve essential hairpins in the viral genome required for replication and infectivity. VDS delivered the genome for minute virus of mice (MVMp) to multiple cancers, including breast, pancreatic, and osteosarcoma. Viral delivery produced functional viral particles that are cytotoxic and infective to neighboring cells. The release of mature virions initiated new rounds of infection and amplified the infection. Using Salmonella for delivery will circumvent the limitations of oncolytic viruses and will provide a new therapy for many cancers.
PubMed: 38799578
DOI: 10.1016/j.isci.2024.109813 -
Frontiers in Immunology 2024None of the typhoid Vi Polysaccharide (ViPS) subunit vaccines incorporate adjuvants, and the immunogenicity of ViPS vaccines (e.g. Typbar TCV and Typhim Vi) is in part...
None of the typhoid Vi Polysaccharide (ViPS) subunit vaccines incorporate adjuvants, and the immunogenicity of ViPS vaccines (e.g. Typbar TCV and Typhim Vi) is in part due to associated TLR4 ligands such as endotoxin present in these vaccines. Since endotoxin content in vaccines is variable and kept very low due to inherent toxicity, it was hypothesized that incorporating a defined amount of a non-toxic TLR4-ligand such as monophosphoryl lipid A in ViPS vaccines would improve their immunogenicity. To test this hypothesis, a monophosphoryl lipid A-based adjuvant formulation named Turbo was developed. Admixing Turbo with Typbar TCV (ViPS-conjugated to tetanus toxoid) increased the levels of anti-ViPS IgM, IgG1, IgG2b, IgG2a/c, and IgG3 in inbred and outbred mice. In infant mice, a single immunization with Turbo adjuvanted Typbar TCV resulted in a significantly increased and durable IgG response and improved the control of bacterial burden compared to mice immunized without Turbo. Similarly, when adjuvanted with Turbo, the antibody response and control of bacteremia were also improved in mice immunized with Typhim Vi, an unconjugated vaccine. The immunogenicity of unconjugated ViPS is inefficient in young mice and is lost in adult mice when immunostimulatory ligands in ViPS are removed. Nevertheless, when adjuvanted with Turbo, poorly immunogenic ViPS induced a robust IgG response in young and adult mice, and this was observed even under antigen-limiting conditions. These data suggest that incorporation of Turbo as an adjuvant will make typhoid vaccines more immunogenic regardless of their intrinsic immunogenicity or conjugation status and maximize the efficacy across all ages.
Topics: Animals; Typhoid-Paratyphoid Vaccines; Mice; Toll-Like Receptor 4; Vaccines, Subunit; Antibodies, Bacterial; Adjuvants, Immunologic; Lipid A; Typhoid Fever; Immunoglobulin G; Female; Ligands; Polysaccharides, Bacterial; Immunogenicity, Vaccine; Adjuvants, Vaccine; Salmonella typhi; Mice, Inbred BALB C
PubMed: 38799439
DOI: 10.3389/fimmu.2024.1383476 -
BioRxiv : the Preprint Server For... May 2024serovar Typhimurium causes acute diarrhea upon oral infection in humans. The harsh and proteolytic environment found in the gastrointestinal tract is the first obstacle...
UNLABELLED
serovar Typhimurium causes acute diarrhea upon oral infection in humans. The harsh and proteolytic environment found in the gastrointestinal tract is the first obstacle that these bacteria face after infection. However, the mechanisms that allow to survive the hostile conditions of the gut are poorly understood. The gene is found in an extensive range of known phyla of bacteria and it encodes a protein that has been shown to inhibit serine proteases. Thus, in the present work we studied the role of of Typhimurium in host-pathogen interactions. We found that Typhimurium Δ strain exhibited lower inflammation in a murine model of induced colitis. The Δ mutant was more susceptible to the action of pancreatin and purified pancreatic elastase. In addition, the lack of led to impaired adhesion to Caco-2 and HT-29 cell lines, related to the proteolytic activity of brush border enzymes. Besides, Δ showed higher susceptibility to lysosomal proteolytic content and intracellular replication defects in macrophages. In addition, we found Ecotin to have a crucial role in against the microbicide action of granules released and neutrophil extracellular traps from human polymorphonuclear leukocytes. Thus, the work presented here highlights the importance of in as countermeasures against the host proteolytic defense system.
IMPORTANCE
The gastrointestinal tract is a very complex and harsh environment. is a successful food borne pathogen, but little is known about its capacity to survive against the proteolysis of the gut lumen and intracellular proteases. Here, we show that Ecotin, a serine protease inhibitor, plays an important role in protecting against proteases present at different sites encountered during oral infection. Our results indicate that Ecotin is an important virulence factor in , adding another tool to the wide range of features this pathogen uses during oral infection.
PubMed: 38798423
DOI: 10.1101/2024.05.15.594389 -
Research Square May 2024Salmonellosis, caused by Salmonella enterica serovar Typhimurium, is a significant global threat. Host immunity limits bacterial replication by inducing hepcidin, which...
Salmonellosis, caused by Salmonella enterica serovar Typhimurium, is a significant global threat. Host immunity limits bacterial replication by inducing hepcidin, which degrades ferroportin, reducing iron transfer. However, this boosts macrophage iron storage, aiding intracellular pathogens like Salmonella. Mice lacking ferritin heavy chain (FTH1) in myeloid cells suffer worsened Salmonella infection. Nuclear receptor co-activator 4 (NCOA4) regulates iron release via FTH1 degradation during low iron, but its role in salmonellosis is unclear. Here, we reveal that myeloid NCOA4 deficiency augments spleen iron levels and increases cellular iron accumulation, oxidative stress, and ferroptosis in bone marrow-derived macrophages. This deficiency also increases susceptibility to Salmonella-induced colitis in mice. Mechanistically, NCOA4 suppresses oxidative stress by directly binding to the E3 ubiquitin ligase Kelch-like ECH-associated protein 1 (KEAP1) and stabilizing the antioxidant transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2). Activation of NRF2 protects myeloid NCOA4 knockout mice from Salmonella-induced colitis. Antioxidant Tempol and myeloid cell-targeted curcumin offer protection against colitis in myeloid NCOA4-deficient mice. A low iron diet and ferroptosis inhibition also mitigate the heightened colitis in these mice. Overexpression of myeloid cell- specific NCOA4 confers protection against Salmonella-induced colitis via upregulating NRF2 signaling. Serum iron was reduced in myeloid NCOA4-overexpressing mice, but not in NCOA4- deficient mice. Targeted serum metabolomics analysis revealed that many lipids were decreased in myeloid NCOA4-deficient mice, while several of them were increased in myeloid NCOA4-overexpressing mice. Together, this study not only advances our understanding of NCOA4/KEAP1/NRF2/ferroptosis axis but also paves the way for novel myeloid cell-targeted therapies to combat salmonellosis.
PubMed: 38798412
DOI: 10.21203/rs.3.rs-4278310/v1