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PubMed2026

Staphylococcus aureus urease is controlled by a complex regulatory network to promote dissemination during CAUTI.

UNLABELLED: Catheter-associated urinary tract infections (CAUTIs) are one of the most common hospital-associated infections in the United States, accounting for >1 million cases annually. One CAUTI pathogen, Staphylococcus aureus, is commonly found persisting asymptomatically in the bladder of catheterized individuals, increasing these individuals' risk of developing infection. Importantly, S. aureus is not only associated with severe symptoms during CAUTI, including bacteremia and septic shock, but it also produces a common uropathogen-associated virulence factor, urease. Despite its importance, urease has only been well-studied in another uropathogen, Proteus mirabilis. While previous studies identified three S. aureus urease regulators, including CodY, CcpA, and Agr, the environmental signals required for expression and activity, and the enzyme's contribution to CAUTI have not been explored. In this study, we demonstrate that post-exponential growth and growth in the urinary tract environment significantly induce S. aureus urease expression and activity. Additionally, we identify SigB, SaeR, and SrrA as novel regulators of urease, and further explore the role of CodY, CcpA, and Agr-previously implicated in urease expression-in urease regulation in the urinary tract environment. Impactfully, we found that the urease promoters of clinical isolates contain genomic changes that enhance urease expression. Furthermore, urease contributes to biofilm formation under catheterized urinary tract-like conditions in vitro and dissemination from the bladder to the kidneys in a mouse CAUTI model. Together, our data not only provide insight into the regulatory pathway controlling S. aureus urease but also emphasize the importance of studying these mechanisms in a model that mimics the urinary environment. IMPORTANCE: In this study, we investigate how regulatory pathways coordinate the expression and activity of urease in response to environmental signals present within the catheterized urinary tract. We show that growth during the post-exponential phase and in conditions that mimic the urinary tract increases urease expression and activity. This finding challenges the dogma that Staphylococcus aureus is a "weak" urease producer. We also identified three novel regulators of S. aureus urease-SigB, SrrA, and SaeR-and show that their respective activation signals can modulate urease expression. Additionally, single-nucleotide changes identified in the urease regulatory pathway of clinical urinary catheter-associated isolates enhance urease expression. Finally, urease promotes biofilm formation under conditions that mimic the catheterized urinary tract and dissemination during catheter-associated urinary tract infections (CAUTIs). Our study provides insight into the complex regulatory mechanisms controlling urease in the urinary tract and highlights the role urease plays in S. aureus CAUTI.

Urease↗

PubMed2026

A novel urease-producing strain effectively induces cadmium biomineralization under low-temperature stress.

Microbially induced carbonate precipitation (MICP) has been widely used to immobilize Cadmium (Cd) in contaminated soils in mining-affected regions. However, its remediation efficacy under low-temperature stress, as well as the nucleation process that regulates Cd biomineralization via carbonate precipitation by psychrophilic bacteria, has yet to be investigated. Here, we isolated Pseudomonas sp. J-6, a novel urease-producing strain from tailings in high-altitude cold regions, exhibiting unparalleled cold adaptability at 5 °C and achieving 95.85 % Cd removal efficiency by MICP at 10 °C. Furthermore, the coprecipitation process of Ca1-xCdxCO3 was clarified through the continuous observation of the precipitates after the low-temperature MICP reaction. The crystal morphology transitioned from loose vaterite in the early stage to a dense square-block morphology in the middle stage. Cd2+ progressively shifted from a surface-bound state to lattice incorporation, ultimately resulting in the formation of stable Cd-substituted calcite crystals. In this process, low temperatures led to the formation of larger, highly ordered Cd-substituted calcite crystals, thereby strengthening Cd sequestration and its long-term stability. In addition, under low-temperature stress, Pseudomonas sp. J-6 induced MICP reaction decreased the bioavailable Cd in alpine slag soil by 44.85 % and enhanced physical properties. In the freeze-thaw cycles, the remediation efficiency remained stable. This study clarified the biomineralization potential in high-altitude cryogenic environments and the nucleation process of Cd biomineralization by psychrophilic bacteria-induced carbonate precipitation, filling a critical research gap in its application under extreme conditions and highlighting its promise for sustainable remediation of heavy metal pollution under low-temperature stress.

Cadmium↗

PubMed2025

Leclercia barmai sp. nov., isolated from worm castings of Eisenia fetida, is a urease-positive, 3-nitropropionic acid and glycerol-consuming bacterium.

A comprehensive polyphasic characterization has validated the unique taxonomic position of a novel bacterium, strain EMC7T, isolated from the worm castings of earthworm, Eisenia fetida, collected from the Centre for Floriculture and Agri-Business Management (COFAM), NBU (26.7072° N, 88.3554° E). Whole-genome sequence of this Gram-stain-negative, facultatively anaerobic, motile, rod-shaped bacterium showed maximum sequence homology with Leclercia adecarboxylata NBRC 102595T, placing it within the genus Leclercia. The genome of EMC7T is 5.03 Mbp with a G + C content of 56.3 mol%. Phylogenetic analyses established its distinctiveness from Leclercia adecarboxylata and Leclercia tamurae. DNA-DNA hybridization (dDDH) value was 23.6%, and the average nucleotide identity (ANI) was 82.1%, both below the thresholds for prokaryotic species differentiation. Predominant fatty acids were C16:0 (29.53%), summed feature 3 (C16:1ω7c/C16:1ω6c, 16.51%), and C18:1ω7c (10.90%). Notably, EMC7T exhibited urease activity and could metabolize 3-nitropropionic acid (3-NPA), glycerol, tellurite, selenate, and selenite, suggesting potential bioremediation applications. Biochemical tests, phenotypic traits, genotypic data, and physiological properties cumulatively differentiated EMC7T from its closest relatives. Based on chemotaxonomic, phenotypic, genomic, and phylogenetic evidence, strain EMC7T represents a novel bacterial species of the genus Leclercia, for which the name Leclercia barmai sp. nov. (type strain EMC7T = MCC 5183T = JCM 36544T) is proposed.

Animals↗

PubMed2026

Alleviation of Helicobacter pylori-Induced Pathogenicity and Gastric Inflammation by Majonoside-R2- and Ginsenoside Rg1-Rich Fractions From Panax vietnamensis Ha Et Grushv.: A Metabolomics-Guided Investigation.

Helicobacter pylori infection remains a major global health concern due to its association with gastric inflammation, ulceration, and gastric malignancies. This study evaluated the effects of Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.) root fractions on H. pylori virulence and host inflammatory responses. UHPLC-MS/MS-based metabolomic profiling coupled with feature-based molecular networking was employed to characterize the chemical profiles of different solvent fractions, identifying the dichloromethane (DCM) fraction as enriched in ginsenosides, particularly the ocotillol-type saponin majonoside R2 (MR2). In vitro assays showed that, despite minimal direct antibacterial activity, the DCM fraction at sub-inhibitory concentrations significantly reduced urease activity, acid tolerance, biofilm formation, and the expression of major virulence genes, including vacA and cagA. In H. pylori-infected AGS gastric epithelial cells, the DCM fraction and MR2 decreased VacA and CagA translocation, suppressed pro-inflammatory signaling and cytokine production, restored antioxidant defenses, and alleviated mitochondrial apoptosis. By contrast, ginsenoside Rg1 selectively modulated host inflammatory and oxidative stress responses without affecting bacterial virulence gene expression. These results demonstrate that Ngoc Linh ginseng root fractions mitigate H. pylori-induced pathogenic effects primarily through anti-virulence and host-directed mechanisms, highlighting their potential relevance for the development of gastric health-promoting functional products.

Helicobacter pylori↗

PubMed2026

Multi-Omic Insights Into Mediterranean Diet-Associated Microbiota.

This study aimed to evaluate the gut microbiota and mycobiota composition, depending on the Mediterranean diet (MD) adherence, using metataxonomics. Combining metagenomics and metatranscriptomics, we also investigate the gene expression level in the bacterial community. Two groups of healthy subjects greatly differing in adherence were selected. Significant differences in microbiota composition were observed between individuals with high adherence (HAMD; mean 10.5 +/- 0.9 points) and low adherence (LAMD; 5.23 +/- 83 points). Notably, the olive oil, vegetable, and fruit consumption presented an important discriminant power between groups. Saccharomyces, Penicillium, and Candida were the most abundant genera. Mycobiota richness was higher in LAMD than in HAMD. Aspergillus was identified as a biomarker for LAMD, whereas Yarrowia, a potential probiotic, was a biomarker for HAMD. Metatranscriptomics indicated that Bacillota was the most metabolically active phylum in the gut microbiota. The low-abundant genus, Methanobrevibacter, showed high transcriptional activity, contributing to the crucial methanogenesis process. Gene expression analyses further highlighted functional differences. Overall, HAMD microbiota presented increased metabolic activity, protein synthesis, and cellular mobility. Overexpression of flagellin and urease genes may enhance immune response in HAMD. Further metatranscriptomic studies are necessary to deepen our understanding of intestinal microbiota transcriptional programs and their interactions with the diet and human health.

Humans↗

PubMed2026

Functional identification of the key gene Eh-fadB in nicosulfuron degradation by Enterobacter hormaechei ES1 based on multi-omics and enzymatic characterization.

Nicosulfuron is a sulfonylurea herbicide with residues that pose ecological risks in agricultural soils. Here we elucidated the degradation mechanism of Enterobacter hormaechei ES1 through whole-genome sequencing, transcriptomics, metabolomics, gene knockout, heterologous expression, and soil bioremediation assays. Under nicosulfuron stress, ES1 upregulated antioxidant enzymes including SOD, POD, and CAT, along with glutathione synthesis, to scavenge excess reactive oxygen species. HPLC-TOF-MS identified degradation intermediates such as ADMP and ASDM, indicating initial cleavage of the sulfonylurea bridge. Integrated multi-omics prioritized Eh-fadB, encoding a fatty acid β-oxidation multifunctional enzyme, as a novel degradative gene. Targeted knockout of Eh-fadB reduced nicosulfuron degradation from 87.6% to 37.04%, while genetic complementation restored nearly full activity. Purified Eh-FadB directly converted nicosulfuron, with optimal performance at 30 °C and pH 5-6; its activity was enhanced by Na+ and Pb2+ but inhibited by Fe3+. Molecular docking and dynamics identified His-450 and Asn-427 as key residues for substrate binding. In contaminated soil, inoculation with ES1 reduced nicosulfuron content within 21 days and promoted recovery of dehydrogenase and urease activities. This study provides the first genetic and biochemical evidence that a FadB-type enzyme participates in nicosulfuron catabolism, supporting sulfonylurea bridge cleavage and its potential for soil bioremediation.

Eh-fadB↗

PubMed2026

Association of IL-10 promoter and IL-12 gene polymorphisms with the risk of symptomatic Helicobacter pylori infection.

BACKGROUND: The host's immune response to Helicobacter pylori (H. pylori) infection is largely determined by its cytokine profile. Genetic variations within crucial immunomodulatory genes, including those for interleukin-10 (IL-10) and interleukin-12 (IL-12), are thought to influence an individual's vulnerability to the infection and its clinical consequences by modifying cytokine production. Nonetheless, research data derived from diverse human populations continue to show inconsistent results. AIM: This case-control analysis sought to examine a potential link between symptomatic H. pylori infection susceptibility in an Iranian population and specific genetic variants in the IL-10 (-1082G > A, -819 C > T) and IL-12 (+ 1188 A > C) genes. METHODS: In this investigation, 68 individuals with confirmed symptomatic H. pylori infection diagnosed by a positive rapid urease test and elevated anti-H. pylori IgG levels exceeding 90 ng/ml via ELISA were enrolled alongside 68 healthy controls. The control group was carefully matched to the patient group based on age, sex, and ethnic background. Genotyping for the IL-10 (-1082G > A, -819 C > T) and IL-12 (+ 1188 A > C) polymorphisms was conducted using the Amplification Refractory Mutation System-PCR (ARMS-PCR) method. To evaluate associations, the distribution of genotypes and alleles between the groups was contrasted using logistic regression, applying additive, dominant, and recessive inheritance models. The strength of any association was expressed as odds ratios (ORs) accompanied by 95% confidence intervals (CIs). RESULTS: The analysis revealed no statistically significant correlations linking the investigated IL-10 and IL-12 gene variants to an increased predisposition for H. pylori infection. A notable methodological observation was the deviation from Hardy-Weinberg equilibrium (HWE) across all studied polymorphisms in the control group. Regarding the IL-10 -1082G > A locus, the AA genotype was associated with a marginally elevated risk estimate; however, this finding was not statistically significant (OR = 3.45, 95% CI: 0.29-41.36; p = 0.327). Likewise, for the IL-12 + 1188 A > C polymorphism, the CC genotype, while more prevalent in the patient cohort, also demonstrated no significant association with infection risk (OR = 1.43, 95% CI: 0.42-4.87; p = 0.567). CONCLUSION: This investigation did not establish a significant link between the specific IL-10 and IL-12 gene variants analyzed and susceptibility to symptomatic H. pylori infection in the studied population. Although minor genetic associations were noted, they lacked statistical significance. Future research with larger sample sizes is required to validate these results and to investigate additional genetic determinants that may affect infection risk.

Humans↗