An allosteric inhibitor of the PhoQ histidine kinase with therapeutic potential against Salmonella infection.

Background: The upsurge of antimicrobial resistance demands innovative strategies to fight bacterial infections. With traditional antibiotics becoming less effective, anti-virulence agents or pathoblockers, arise as an alternative approach that seeks to disarm pathogens without affecting their viability, thereby reducing selective pressure for the emergence of resistance mechanisms.

Objectives: To elucidate the mechanism of action of compound N'-(thiophen-2-ylmethylene)benzohydrazide (A16B1), a potent synthetic hydrazone inhibitor against the Salmonella PhoP/PhoQ system, essential for virulence.

Insertion sequence IS6770 modulates potassium symporter kup transcription in Enterococcus faecalis JH2-2 under low pH conditions.

Enterococcus faecalis is a phylogenetically and industrially relevant microorganism associated with Lactic Acid Bacteria. Some strains of this bacterium are employed as probiotics in commercial applications, while others serve as the principal component in starter cultures for artisanal regional cheese production. However, over the last decade, this species has emerged as an opportunistic multiresistant pathogen, raising concerns about its impact on human health.

Enhancing colistin efficacy against Salmonella infections with a quinazoline-based dual therapeutic strategy.

Colistin remains one of the last-resort therapies for combating infections caused by multidrug-resistant (MDR) Enterobacterales, despite its adverse nephro- and neuro-toxic effects. This study elucidates the mechanism of action of a non-antibiotic 4-anilinoquinazoline-based compound that synergistically enhances the effectiveness of colistin against Salmonella enterica. The quinazoline sensitizes Salmonella by deactivating intrinsic, mutational, and transferable resistance mechanisms that enable Salmonella to counteract the antibiotic impact colistin, together with an induced disruption to the electrochemical balance of the bacterial membrane.

Metagenomic approach to infer rumen microbiome derived traits of cattle.

Ruminants enable the conversion of indigestible plant material into animal consumables, including dairy products, meat, and valuable fibers. Microbiome research is gaining popularity in livestock species because it aids in the knowledge of illnesses and efficiency processes in animals. In this study, we use WGS metagenomic data to thoroughly characterize the ruminal ecosystem of cows to infer positive and negative livestock traits determined by the microbiome.

Intranasal trans-sialidase-based vaccine against Trypanosoma cruzi triggers a mixed cytokine profile in the nasopharynx-associated lymphoid tissue and confers local and systemic immunogenicity.

Trypanosoma cruzi, the agent of Chagas disease, can infect through conjunctive or oral mucosas. Therefore, the induction of mucosal immunity by vaccination is relevant not only to trigger local protection but also to stimulate both humoral and cell-mediated responses in systemic sites to control parasite dissemination. In a previous study, we demonstrated that a nasal vaccine based on a Trans-sialidase (TS) fragment plus the mucosal STING agonist c-di-AMP, was highly immunogenic and elicited prophylactic capacity.

Redundant potassium transporter systems guarantee the survival of under stress conditions.

is able to grow in media at pH from 5.0 to 9.0 and a high concentration of NaCl (8%).

Nasal immunization with a L. lactis-derived trans-sialidase antigen plus c-di-AMP protects against acute oral T. cruzi infection.

The new generation of vaccines for Chagas disease, are focused to induce both humoral and cellular response to effectively control Trypanosoma cruzi parasites. The administration of vaccine formulations intranasally has the advantage over parenteral routes that can induce a specific response at mucosal and systemic levels. This study aimed to evaluate and compare the immunogenicity and prophylactic effectiveness of two Trans-sialidase (TS)-based mucosal vaccines against T.

Genomic analysis revealed conserved acid tolerance mechanisms from native micro-organisms in fermented feed.

Aims: Fermented feed is an agricultural practice used in many regions of the world to improve the growth performance of farm animals. This study aimed to identify and evaluate the lactic acid bacteria and yeast involved in the production of fermented feed.

Methods And Results: We isolated and described two micro-organisms from autochthonous microbiota origin present in a regional feed product, Lactobacillus paracasei IBR07 (Lacticaseibacillus paracasei) and Kazachstania unispora IBR014 (Saccharomyces unisporum).

Diversity of volatile organic compound production from leucine and citrate in Enterococcus faecium.

Enterococcus faecium is frequently isolated from fermented food; in particular, they positively contribute to the aroma compound generation in traditional cheese. Citrate fermentation is a desirable property in these bacteria, but this feature is not uniformly distributed among E. faecium strains.

Enterococcus faecalis MalR acts as a repressor of the maltose operons and additionally mediates their catabolite repression via direct interaction with seryl-phosphorylated-HPr.

Enterococci are gram-positive pathogens and lead to cause hospital-acquired infections worldwide. Central carbon metabolism was shown as highly induced in Enterococcus faecalis during infection context. Metabolism of α-polysaccharides was previously described as an important factor for host colonisation and biofilm formation.

Implications of the expression of Enterococcus faecalis citrate fermentation genes during infection.

Citrate is an ubiquitous compound in nature. However, citrate fermentation is present only in a few pathogenic or nonpathogenic microorganisms. The citrate fermentation pathway includes a citrate transporter, a citrate lyase complex, an oxaloacetate decarboxylase and a regulatory system.

Genetic Engineering of Co-producing Antigen and the Mucosal Adjuvant 3' 5'- cyclic di Adenosine Monophosphate (c-di-AMP) as a Design Strategy to Develop a Mucosal Vaccine Prototype.

is a promising candidate for the development of mucosal vaccines. More than 20 years of experimental research supports this immunization approach. In addition, 3' 5'- cyclic di-adenosine monophosphate (c-di-AMP) is a bacterial second messenger that plays a key role in the regulation of diverse physiological functions (potassium and cellular wall homeostasis, among others).

Genetic and phenotypic features defining industrial relevant Lactococcus lactis, L. cremoris and L. lactis biovar. diacetylactis strains.

Lactococcus lactis strains constitute one of the most important starter cultures for cheese production. In this study, a genome-wide analysis was performed including 68 available genomes of L. lactis group strains showing the existence of two species (L.

Safety assessment and functional properties of four enterococci strains isolated from regional Argentinean cheese.

The members of the Enterococcus genus are widely distributed in nature. Its strains have been extensively reported to be present in plant surfaces, soil, water and food. In an attempt to assess their potential application in food industry, four Enterococcus faecium group-strains recently isolated from Argentinean regional cheese products were evaluated using a combination of whole genome analyses and in vivo assays.

Enzymes Required for Maltodextrin Catabolism in Enterococcus faecalis Exhibit Novel Activities.

Maltose and maltodextrins are formed during the degradation of starch or glycogen. Maltodextrins are composed of a mixture of maltooligosaccharides formed by α-1,4- but also some α-1,6-linked glucosyl residues. The α-1,6-linked glucosyl residues are derived from branching points in the polysaccharides.

Enterococcus faecalis Uses a Phosphotransferase System Permease and a Host Colonization-Related ABC Transporter for Maltodextrin Uptake.

Maltodextrin is a mixture of maltooligosaccharides, which are produced by the degradation of starch or glycogen. They are mostly composed of α-1,4- and some α-1,6-linked glucose residues. Genes presumed to code for the maltodextrin transporter were induced during enterococcal infection.

Functional Analysis of the Citrate Activator CitO from Enterococcus faecalis Implicates a Divalent Metal in Ligand Binding.

The regulator of citrate metabolism, CitO, from Enterococcus faecalis belongs to the FCD family within the GntR superfamily. In the presence of citrate, CitO binds to cis-acting sequences located upstream of the cit promoters inducing the expression of genes involved in citrate utilization. The quantification of the molecular binding affinities, performed by isothermal titration calorimetry (ITC), indicated that CitO has a high affinity for citrate (K D = 1.

Draft Genome Sequences of Four Enterococcus faecium Strains Isolated from Argentine Cheese.

We report the draft genome sequences of four Enterococcus faecium strains isolated from Argentine regional cheeses. These strains were selected based on their technological properties, i.e.

Draft Genome Sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a Citrate-Fermenting Strain.

We report the draft genome sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a natural strain isolated from artisanal cheese from northwest Argentina.

Aroma compounds generation in citrate metabolism of Enterococcus faecium: Genetic characterization of type I citrate gene cluster.

Enterococcus is one of the most controversial genera belonging to Lactic Acid Bacteria. Research involving this microorganism reflects its dual behavior as regards its safety. Although it has also been associated to nosocomial infections, natural occurrence of Enterococcus faecium in food contributes to the final quality of cheese.

Genomic comparative analysis of the environmental Enterococcus mundtii against enterococcal representative species.

Background: Enterococcus mundtii is a yellow-pigmented microorganism rarely found in human infections. The draft genome sequence of E. mundtii was recently announced.

Expression of the agmatine deiminase pathway in Enterococcus faecalis is activated by the AguR regulator and repressed by CcpA and PTS(Man) systems.

Although the agmatine deiminase system (AgDI) has been investigated in Enterococcus faecalis, little information is available with respect to its gene regulation. In this study we demonstrate that the presence of exogenous agmatine induces the expression of agu genes in this bacterium. In contrast to the homologous and extensively characterized AgDI system of S.

Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6'-phosphate phosphatase (MapP).

Similar to Bacillus subtilis, Enterococcus faecalis transports and phosphorylates maltose via a phosphoenolpyruvate (PEP):maltose phosphotransferase system (PTS). The maltose-specific PTS permease is encoded by the malT gene. However, E.

Biochemical and genetic characterization of the Enterococcus faecalis oxaloacetate decarboxylase complex.

Enterococcus faecalis encodes a biotin-dependent oxaloacetate decarboxylase (OAD), which is constituted by four subunits: E. faecalis carboxyltransferase subunit OadA (termed Ef-A), membrane pump Ef-B, biotin acceptor protein Ef-D, and the novel subunit Ef-H. Our results show that in E.

Fine-tuned transcriptional regulation of malate operons in Enterococcus faecalis.

In Enterococcus faecalis, the mae locus is constituted by two putative divergent operons, maePE and maeKR. The first operon encodes a putative H(+)/malate symporter (MaeP) and a malic enzyme (MaeE) previously shown to be essential for malate utilization in this bacterium. The maeKR operon encodes two putative proteins with significant similarity to two-component systems involved in sensing malate and activating its assimilation in bacteria.