Search Results (8,872)

Background: Canine otitis externa caused by Pseudomonas aeruginosa is frequently chronic and treatment refractory, yet integrated historical phenotype–genotype data remain limited. We characterized an archival Hungarian collection obtained in 2010 and 2017. Methods: Broth microdilution minimum inhibitory concentrations (MICs) were determined for 67 isolates against 13 antimicrobial agents and chlorhexidine, and 59 isolates had matched long-read whole-genome assemblies. Resistance-associated determinants were identified using the Comprehensive Antibiotic Resistance Database, and their predicted proximity to mobile genetic elements and plasmid-like contigs was evaluated. Results: Current canine Clinical and Laboratory Standards Institute breakpoints classified 59/67 isolates (88.1%) as enrofloxacin resistant and 43/67 (64.2%) as marbofloxacin resistant. European Committee on Antimicrobial Susceptibility Testing epidemiological cut-off values identified non-wild-type subsets for ciprofloxacin (7/67), tobramycin (4/67), imipenem (1/67), and piperacillin–tazobactam (51/67), whereas all isolates remained within the available wild-type distributions for ceftazidime, gentamicin, and amikacin. No continuous MIC distribution changed significantly between sampling years after false-discovery-rate correction, although categorical marbofloxacin resistance decreased from 87.5% in 2010 to 42.9% in 2017. Resistance-gene screening identified 64 unique determinants, including near-universal efflux-system components, PDC and OXA-50-like β-lactamases, APH(3′)-IIb, arnA, and basS. The fluoroquinolone-associated determinant crpP occurred in 37/59 genomes and was located on plasmid-predicted contigs in six isolates. No determinant–MIC association remained significant after correction for multiple testing. Conclusions: The discordance between conserved resistance-gene repertoires and heterogeneous MICs demonstrates that sequence-based detection alone is insufficient for therapeutic inference. Integrated phenotypic and genomic surveillance is therefore required to support evidence-based antimicrobial stewardship in canine pseudomonal otitis. Full article

Background: Antimicrobial resistance (AMR) remains a major public health threat in Italy, where high incidence and mortality persist. In this study we aimed to describe national and regional trends in AMR rates from 2015 to 2024. Methods: We conducted an ecological time-series analysis using publicly available data from the Italian AMR surveillance system (AR-ISS). We included six priority pathogens: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE-faecium), third-generation cephalosporin-resistant Escherichia coli (3GCREC), carbapenem-resistant Klebsiella pneumoniae (CRKP), Pseudomonas aeruginosa (CRPA), and Acinetobacter spp. (CRAS). We analyzed annual resistance rates at national and regional level. Temporal trends were estimated using linear regression models, with calendar year as the independent variable. Regression coefficients, 95% CIs, and p-values were used to assess direction and significance. Relative percentage changes were calculated for 2015–2024 and, when relevant, for 2023–2024. Results: Resistance declined over time for four of six pathogens, but increased markedly for VRE-faecium, from 11.1% to 34.9%. Significant downward trends were observed for MRSA (β = −0.91, 95% CI: −1.35; −0.48, p = 0.0013), 3GCREC (β = −0.53, 95% CI: −0.99; −0.06, p = 0.0304), CRKP (β = −0.94, 95% CI: −1.35; −0.53, p = 0.0008), and CRPA (β = −0.86, 95% CI: −1.44; −0.27, p = 0.0095); VRE-faecium showed a strong upward trend (β = +2.76, 95% CI: 2.58; 2.94, p < 0.0001). CRAS remained consistently high throughout the study period. Considerable regional heterogeneity was observed across pathogens and geographical areas. Conclusions: Despite progress for several pathogens, AMR remains a critical challenge in Italy. The persistent increase in VRE-faecium and the high burden of CRAS support the need for strengthened surveillance, stewardship, and region-specific infection prevention interventions. Full article

The fate of heavy metals in agricultural soils is governed by organo-mineral–microbial interactions, which predictive models often fail to capture. The competitive sorption mechanisms of Cd(II) and Cu(II) on montmorillonite/kaolinite composites (Mont/Kao) functionalized with humic acid (HA) and Pseudomonas putida (P. p), a model system representative of contaminated agricultural soils, were investigated. Batch experiments, XRD, FTIR, and thermodynamic analysis reveal that metal retention is a non-additive function of competing interfacial processes. Bacterial biomass dominated sorption, accounting for >50% of total metal uptake, with capacity ranked as: P. p > Mont/Kao-P. p > Mont/Kao-HA-P. p > Mont/Kao-HA > Mont/Kao. Humic acid exerts a dual, concentration-dependent role: Low levels enhanced adsorption via mineral dispersion, while high levels induced surface masking, suppressing bacterial binding sites. Competition was highly asymmetric: Cd(II) reduced Cu(II) maximum adsorption capacity by 75.5% in the Mont/Kao-HA system by preferentially occupying montmorillonite interlayer sites, whereas Cu(II) inhibited Cd(II) below pH 6. Single-metal sorption was characterized by positive ΔS° (32.96–58.89 J·mol⁻¹·K⁻¹), indicative of inner-sphere complexation, while negative ΔS° under competitive conditions signals a transition to outer-sphere complexation. This work provides mechanistic insights into site masking, competitive displacement, and ternary cation bridging controlling metal immobilization in organo-mineral assemblages. Full article

Hemp (Cannabis sativa L.) inflorescences have been extensively characterized for their bioactive compounds, whereas less information is available on hemp leaves despite their potential as a source of nutrients and phytochemicals. This study compared leaves and inflorescences of four organically grown hemp cultivars (Finola, Futura 75, Dioica, and Kompolti) in terms of cannabinoid, terpene, and fatty acid profiles, lipid quality indices, and in vitro antibacterial activity. Antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was evaluated using MIC, MBC, and time–kill assays. Total cannabinoid content was approximately 2.7-fold higher in inflorescences than in leaves, which were also generally richer in terpenes. Leaves showed a more favorable fatty acid profile, with higher n-3 polyunsaturated fatty acid proportions and a lower n-6/n-3 ratio. All extracts exhibited antibacterial activity. Among the tested bacteria, S. aureus was the most susceptible to the hemp extracts, with both growth inhibition and bactericidal activity observed at the lowest tested concentration (MIC/MBC = 0.005%), compared with 0.625% for E. coli and 1.25–2.5% for P. aeruginosa, depending on the extract. Finola and Kompolti inflorescence extracts showed the fastest bactericidal activity against S. aureus. These findings demonstrate distinct and complementary characteristics of hemp leaves and inflorescences and provide a basis for further investigation of their potential relevance to canine nutrition. Full article

The present study investigated the chemical composition, antimicrobial, insecticidal, and food preservation potential of Ligusticum chuanxiong CO₂ oil (LCCO) standardised to a ligustilide content of ≥35%. The volatile composition of LCCO was characterised by GC-MS and found to be dominated by cis-ligustilide (63.3%), senkyunolide (15.8%), 3-butylidenephthalide (5.4%), and trans-neocnidilide (4.9%). In vitro antimicrobial activity was evaluated by disc diffusion and broth microdilution against six bacterial and five yeast reference strains. The largest inhibition zones were observed against Enterococcus faecalis (14.33 mm) and Staphylococcus aureus (13.67 mm). MIC₅₀ values ranged from 0.064 mg/mL (Yersinia enterocolitica) to 3.492 mg/mL (Candida tropicalis), while MIC₉₀ values ranged from 0.151 to 3.800 mg/mL. In situ vapour-phase antimicrobial activity was evaluated on pear, banana, white radish, and carrot at concentrations of 62.5–500 µL/L, demonstrating a clear concentration-dependent inhibitory effect across all tested food matrices and microorganisms. Insecticidal activity against Callosobruchus maculatus and Megabruchidius dorsalis was confirmed under fumigation conditions, with LC₅₀ values of 17.50% and 20.99% and LC90 values of 83.10% and 87.60%, respectively. The effect of LCCO, applied alone and in combination with vacuum packaging, on the microbiological quality of fresh white radish was evaluated over 28 days of refrigerated storage at 4 °C. The combined treatment resulted in the lowest total viable count (2.75 log CFU/g) and coliform bacteria count (2.58 log CFU/g) on day 28. A total of 404 bacterial isolates were identified using MALDI-TOF MS Biotyper, comprising 22 species. Acinetobacter pittii was the predominant species (33%), followed by Pantoea agglomerans (7%) and Serratia nematodiphila (7%). No Pseudomonas species were recovered from the EO vacuum treatment. Overall, these findings demonstrate the potential of LCCO, particularly in combination with vacuum packaging, as a natural antimicrobial agent for the postharvest preservation of fresh white radish. Full article

Spontaneously fermented camel milk from Xinjiang is valued for its nutrition but faces quality inconsistency due to complex microbial ecosystems. This study investigated how regional microbial communities correlate with volatile flavor profiles. Nine samples from three distinct areas—Dabancheng, Hami, and Keping—were analyzed using bacterial 16S rRNA gene and fungal ITS region amplicon sequencing combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-TOF MS). Bacterial communities were dominated by Firmicutes and Proteobacteria, while Ascomycota and Basidiomycota prevailed among fungi. Dominant genera varied by region: Lactobacillus and Dekkera in Dabancheng; Lactobacillus and Dipodascus in Hami; Lactococcus and Cutaneotrichosporon in Keping. Flavor profiles also diverged, with Dabancheng being rich in esters, alcohols, and ketones; Hami featuring hydrocarbons and alcohols; and Keping containing elevated hydrocarbons, alcohols, and esters. Key statistical associations were identified: Lactobacillus, Rahnella, and Acetobacter were positively associated with propene and 3-decyn-2-ol (VIP > 1.0, |r| > 0.8), while Pseudomonas, Lactococcus, and Klebsiella showed negative correlations with vinyl n-caproate. These findings reveal statistical associations between geographic origin, specific microbial taxa, and flavor attributes, providing a scientific foundation that may inform future efforts toward developing targeted starter cultures pending microbial isolation and functional validation. Full article

Pseudomonas syringae pv. actinidiae (Psa) is the most destructive pathogen of kiwifruit, and the absence of curative measures makes the management of Psa-induced kiwifruit bacterial canker (KBC) particularly challenging. Elettaria cardamomum produces an essential oil (CAR) rich in bioactive compounds with demonstrated potential to act directly against Psa, but its mechanisms of action remain insufficiently explored. Here, we investigated CAR’s mode of action in plants with established mild KBC symptoms, and assessed its potential as a plant elicitor. In the in planta assay, CAR application (0.1% w/v, applied 7 days after inoculation) reduced KBC symptoms, with the strongest effect observed 14 days after treatment (DAT). However, CAR did not significantly affect oxidative stress biomarkers, antioxidant system, pigments and primary metabolism, or the expression of target genes related to systemic acquired resistance or salicylic acid and jasmonic acid pathways. For instance, Psa inoculation significantly upregulated PR1 (≈5.4-fold) and PR5 (≈4.3–5.5-fold), irrespective of CAR application. Complementary in vitro assays revealed a transient, phase-dependent antimicrobial activity of CAR: although the effect disappeared by 32 h in liquid-phase assay and no inhibition was observed under vapor-phase exposure, a strong reduction in Psa viable cells (79.7%) was observed after 8 h exposure in the liquid phase. This study demonstrates that CAR exerts a direct, albeit transient, antibacterial effect against Psa, conferring curative activity when applied to plants with mild KBC symptoms. Consequently, repeated applications may be required to maintain disease suppression, as CAR does not appear to induce a sustained preventive defense response in the host. Full article

In 2024, an accident involving two tankers in the Kerch Strait resulted in the release of approximately 2400 tons of fuel oil into the Black Sea, causing significant contamination of seawater and the coastal zone. This study presents the first microbiological and molecular–ecological assessment of prokaryotic community composition and hydrocarbon-oxidizing bacteria (HOB) in coastal seawater and sand near Anapa (Russian Federation) following the spill. The taxonomic composition of nine samples was analyzed using high-throughput sequencing of 16S rRNA genes (V3–V4 regions), identifying Bacteria as the dominant domain (85.3–99.8%). In seawater samples, bacteria of the phyla Pseudomonadota, Cyanobacteriota, and Bacteroidota and archaea of the phyla Thermoplasmatota and Crenarchaeota predominated. Eighteen aerobic bacterial strains, including members of the genera Shewanella, Pseudoalteromonas, Halopseudomonas, Marinomonas, Pseudomonas, Vibrio, Alcanivorax, Ectopseudomonas, Nitratireductor, and Echinicola, were isolated from the zone of fuel oil spill. Several isolates demonstrated heavy oil degradation and biosurfactant production. Screening of collection strains isolated from other habitats revealed that Rhodococcus erythropolis TG65 and Marinobacter lutaoensis Pd1 and Pd2 degraded 92–94% of fuel oil n-alkanes. Elevated dissolved iron concentrations in the seawater indicate the possibility of a metabolic coupling between hydrocarbon oxidation and microbial iron reduction, mediated by indigenous Shewanella and Pseudomonas species. These findings indicate that indigenous HOB may contribute to the natural attenuation of aliphatic hydrocarbons in fuel oil. Full article

Background: Hospital water systems are major environmental reservoirs of Pseudomonas aeruginosa, but evidence on the long-term impact of Water Safety Plans (WSPs) on environmental prevalence, antimicrobial resistance, and biofilm-forming ability remains limited. This study evaluated the long-term occurrence of P. aeruginosa in a hospital water distribution system over a 15-year surveillance period. Methods: A 15-year environmental surveillance study was conducted in a tertiary-care hospital in Northern Italy. Water samples were cultured for P. aeruginosa, and recovered isolates were assessed for antimicrobial susceptibility and biofilm-forming ability. Temporal trends were analysed using generalized linear and segmented logistic regression models. Results: Among 1696 water samples, the overall prevalence of P. aeruginosa was 2.93%, with a significant annual decline of 12% (OR 0.88, 95% CI 0.82–0.94; p < 0.001). Segmented regression identified a marked reduction after the fourth year (OR 0.18, 95% CI 0.06–0.55; p = 0.003). Over time, isolates shifted toward weak or non-biofilm-producing phenotypes while maintaining high antimicrobial susceptibility, with only one multidrug-resistant isolate detected. Conclusions: Long-term surveillance integrated within a comprehensive WSP was associated with reduced P. aeruginosa contamination, decreased biofilm-forming ability, and persistently low antimicrobial resistance. Full article

The degradation of Calcisols in the arid regions of Central Asia constrains sustainable agricultural production because of low organic matter content, poor aggregate stability, nutrient limitations, and increasing climatic stress. This study evaluated a rhizosphere engineering approach based on the native plant growth-promoting bacterium Pseudomonas veronii Ps-S/Sh-1503/2022 for the rehabilitation of degraded Calcisols. Four-year field experiments (2022–2025) using Sorghum bicolor assessed plant growth, rhizosphere microbial indicators, physiological responses, pathogen suppression, crop productivity, and implementation feasibility through economic and environmental assessments. Inoculation with P. veronii increased root depth by 45%, improved aboveground biomass, increased the ratio of culturable bacteria to Fusarium spp. from 6.1 to 10.3, and reduced Fusarium abundance by 29.4%. Structural equation modeling suggested that trophic support (42.1%), aggregate stabilization (27.4%), biocontrol (23.3%), and defense-related responses (7.2%) were the principal pathways associated with soil rehabilitation. Economic assessment indicated that the combined inoculation and mineral fertilization treatment provided the highest profitability, while environmental assessment estimated potential reductions in mineral fertilizer use and greenhouse gas emissions. These findings suggest that rhizosphere engineering using a native P. veronii strain represents a promising, economically viable, and climate-smart approach for improving the biological functioning of degraded Calcisols and supporting sustainable agricultural production. Full article

Agricultural intensification with synthetic fertilisers has systematically disrupted soil organic carbon (SOC), influenced rhizosphere networks, and affected human health via the soil–human microbial continuum. Plant Growth-Promoting Microorganisms (PGPMs) can restore biogeochemical cycles; however, field performance varies due to spatial stoichiometric variation. In order to visualise the problem and provide a potential solution, we use global soil carbon-to-nitrogen (C/N) ratio stratification over three depth profiles (0–5, 5–15, and 15–30 cm) to create a potential spatially explicit framework for site-specific PGPM application. In comparison to contemporary models that attribute stable soil organic matter creation mostly to microbial necromass buildup as mineral-associated organic matter (MAOM) via the microbial carbon pump, we assess diazotrophic nitrogen fixation, phosphate solubilisation, and glomalin-mediated aggregation. According to stoichiometric analysis, low C/N ratios (<10:1) increase organic matter mineralisation via priming effects, resulting in clay compaction and sandy soil desiccation, while wide ratios (>30:1) cause microbial nitrogen immobilisation (“nitrogen depression”). To mitigate these limitations, we proposed depth-stratified inoculation, applying chemotactic taxa (Variovorax paradoxus) at 15–30 cm in carbon-depleted subsoils; co-inoculating diazotrophs and arbuscular mycorrhizae (Rhizophagus irregularis) at 5–15 cm for stoichiometric balance and phosphorus acquisition and deploying exopolysaccharide-producing and 1-aminocyclopropane-1-carboxylate (ACC) deaminase-active taxa (Pseudomonas putida, Funneliformis mosseae) at 0–5 cm for erosion. In conclusion, in order to maximise fertiliser use efficiency, improve structural stability, and protect metabolic health within the interdisciplinary One Health framework, we assess the shift toward trait-based, multi-kingdom Synthetic Microbial Communities (SynComs), assembled via genomic metabolic reconstructions and machine learning. We explicitly acknowledge methodological limits in existing field applications, such as substantial spatial variability, equipment constraints, and biotic competition, putting scientific validity ahead of generalised efficacy. Full article

Yak meat faces limitations in the packaging methods available to extend its shelf life and maintain quality. This study compared the effects of tray packaging (YM), vacuum packaging (YZ) and 70% O₂/30% CO₂ modified-atmosphere packaging (YP) on the extension efficiency of yak longissimus dorsi muscles stored at 4 °C. Physicochemical parameters and total viable counts (TVCs) were measured for all three groups, while 16S rRNA sequencing and untargeted metabolomics were performed only on YM and YP samples to explore the mechanisms underlying quality differences. YP treatment significantly delayed the pH increase and color deterioration compared with YM and YZ. Furthermore, YP samples exhibited lower increases in TVB-N, TVC, and drip loss than YZ and YM samples during storage. The genera Brochothrix, Macrococcus, Photobacterium, Delftia, Acinetobacter, Pseudomonas, and Lactococcus were considered predominant spoilage organisms of yak meat. Notably, Lactococcus and Pseudomonas showed a significantly decreased proportional representation in YP samples over the storage period. Through untargeted metabolomics, a total of 818 metabolites were identified. Several pathways, including 2-oxocarboxylic acid metabolism, histidine metabolism, biosynthesis of amino acids, and D-amino acid metabolism, were identified as the main pathways influencing the metabolic differences between the YP and YM samples near spoiled stages. Pearson correlation analysis showed that bacterial genera such as Macrococcus, Photobacterium, Pseudomonas, Lactococcus, and Enhydrobacter were significantly correlated with key differential metabolites. Furthermore, 1-methylhistidine, 3-methylhistidine, alpha-ketoglutaric acid, PC 34:2, ergothioneine, anserine, LPC 16:0, and L-methionine sulfone were positively correlated with predominant spoilage microorganisms. These findings enhance our understanding of the spoilage characteristics of yak meat stored under the most prevalent commercial option (tray packaging) and the most promising modified-atmosphere packaging alternative (70% O₂/30% CO₂ MAP). Full article

Determining the oxygen barrier packaging material is crucial for maintaining the quality and freshness of chilled chicken during low-temperature storage. Chilled chicken was packaged in three materials with different oxygen permeability: medium-oxygen-barrier packaging (MORP, 23.95 cm³/(m²·24 h·0.1 MPa)), low-oxygen-barrier packaging (LORP, 1631.44 cm³/(m²·24 h·0.1 MPa)), and polyethylene packaging (OPP, 10,600.00 cm³/(m²·24 h·0.1 MPa)). The packaged samples were then stored at 4 °C for 9 d. Compared to the OPP group, where Pseudomonas, Acinetobacter, and Lactobacillus dominated, MORP and LORP significantly inhibited Pseudomonas growth, resulting in slower microbial population growth during storage. Owing to the distinct composition of dominant spoilage bacteria, the LORP group demonstrated significantly lower levels of sulfide and nitrogen oxides during storage compared to other groups. Within the first 7 days, the LORP group exhibited markedly lower TVB-N levels in comparison to both the MORP and OPP groups. During the late storage stage, the muscle fiber structure in both the MORP and LORP groups remained relatively intact. In summary, packaging materials with low to medium barrier properties are more effective in maintaining chicken freshness and extending its shelf life to up to 9 days. This method potentially provides an effective foundation for maintaining the quality of poultry meat. Full article

Systemic biologicals have emerged as a disruptive technology for overcoming the limitations of conventional biologicals. The effectiveness of systemic and conventional biological products in improving the growth and yield of two carrot cultivars was compared. Carrot plants were inoculated with either systemic or conventional biofertilizers and nematicides, and various growth parameters and yields were compared. As expected, the first indicator of the proper functioning of the systemic biofertilizer was increased chlorophyll content (two-variety averages: systemic = 17.1, conventional = 11.8, control = 10.9 mg g⁻¹ FW). The results indicated the superior performance of the systemic biologicals in carrot production. The two-variety average yield increased by 11.92 t ha⁻¹ (32%) in plants inoculated with systemic biologicals compared with the control plants and by 6.62 t ha⁻¹ (15.4%) compared with plants inoculated with conventional products (p ≤ 0.05). For the biological nematicides, the two-variety average damage rate was 10.15% in plants treated with the systemic bionematicide, 21.15% in plants treated with the conventional bionematicide, and 31.6% in non-inoculated plants. Analyses revealed the presence of microorganisms in plants inoculated with systemic biologicals, although beneficial fungi were detected at relatively low levels. In conclusion, systemic products offer a more robust and consistent technology for improving crop health and yield and are considered the next generation of biologicals. Full article

Pseudomonas aeruginosa (PA) is a clinically relevant opportunistic pathogen whose persistence and antimicrobial tolerance are largely driven by biofilm formation and quorum-sensing (QS)-regulated virulence. Targeting QS has therefore emerged as an antivirulence strategy that attenuates pathogenicity without exerting strong selective pressure on bacterial growth. This systematic review (2020–2024) analyzes recent advances in the identification of QS inhibitors against PA, emphasizing studies that integrate in silico approaches. Forty-six studies met the inclusion criteria. All employed molecular docking, and 36.9% (n = 17) incorporated molecular dynamics simulations. While valuable for initial detection, these computational predictions have inherent limitations in accurately estimating binding energy and conformational dynamics, requiring empirical validation to confirm actual biological activity. Approximately one-fifth of the studies were exclusively computational, whereas the remainder combined in silico screening with in vitro and, in some cases, in vivo assays. The most frequently investigated QS regulators were LasR, PqsR, and RhlR, alongside additional virulence-associated proteins. The evaluated compounds encompassed phytochemicals, synthetic molecules, nanomaterials and natural product-derived compounds, several of which demonstrated experimental evidence of biofilm attenuation and reduction in QS-regulated virulence factors. Overall, the findings highlight the value of integrating computational and experimental strategies to rationally prioritize antivirulence candidates. However, the intrinsic complexity and redundancy of the QS network suggest that future research should increasingly focus on multitarget approaches and on the exploration of chemically diverse and previously underexplored compound libraries to improve efficacy against PA biofilms. Full article