Search Results (8,569)

Plant-parasitic nematodes (PPNs) rank among the most economically destructive soilborne pathogens worldwide, causing annual crop losses estimated at USD 125–175 billion. Traditional management of plant parasitic nematodes has depended significantly on synthetic nematicides; however, increasing regulatory constraints, environmental pollution, and the rise of resistant nematode populations have generated an urgent need for sustainable alternatives. Humic substances (HS), comprising humic acids, fulvic acids, and humins derived primarily from leonardite and lignite, represent biologically active components of soil organic matter. Their different functional groups, like carboxylic, phenolic, and carbonyl groups, have direct nematicidal and nematostatic effects by stopping eggs from hatching, slowing down juvenile development, and lowering infectivity. They also indirectly improve soil structure, nutrient bioavailability, and the composition of the rhizosphere microbiome. Plant growth-promoting rhizobacteria (PGPR), particularly Bacillus spp. and Pseudomonas spp., suppress PPN populations through antibiotic biosynthesis, cuticle-degrading hydrolytic enzymes, nematostatic volatile organic compounds, and elicitation of induced systemic resistance (ISR). This review methodically analyzes the individual and synergistic processes by which HS and PGPR inhibit PPNs and enhance plant growth. Humic compounds strongly promote PGPR rhizosphere colonization, augmenting microbial metabolic activity and bioinoculant stability, hence producing combinatorial suppressive effects unattainable by either input independently. The combined HS-PGPR approach is reliable and environmentally sustainable for comprehensive nematode control, requiring multidisciplinary research to achieve global sustainable agriculture. Full article

Background/Objectives: Patients in long-term care hospitals (LTCHs) are at increased risk of harboring antimicrobial-resistant organisms due to frequent healthcare exposure and multiple comorbidities. This retrospective observational study aimed to compare the antimicrobial susceptibility of bacterial isolates from LTCH-onset infections (LTCHIs) with those from community-acquired infections (CAIs) in elderly patients. Methods: This study was conducted at a 700-bed urban tertiary university hospital and included patients aged ≥65 years with positive cultures for bacteremia, lower respiratory tract infections (LRTIs), or urinary tract infections (UTIs) within 48 h of admission. Medical records, including antimicrobial susceptibility test results, were reviewed for a total of 1780 patients and their isolates. Antimicrobial susceptibility patterns were compared between LTCHI and CAI patients. Results: Patients with LTCHI exhibited significantly higher antimicrobial non-susceptibility than those with CAIs across multiple pathogens and antimicrobial classes (p < 0.05). In bacteremia, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae from LTCHI cases showed increased non-susceptibility to β-lactams and fluoroquinolones. In LRTIs, Pseudomonas aeruginosa and Acinetobacter baumannii demonstrated high non-susceptibility to carbapenems (52.9% and 90%, respectively) and aminoglycosides. In UTIs, LTCHI isolates exhibited broader resistance among Enterobacterales and P. aeruginosa. Notably, the proportion of multidrug-resistant organisms, including carbapenem-resistant Enterobacterales (15.4–50.0%) and carbapenem-resistant Acinetobacter baumannii (90.5%), was substantially higher in the LTCHI group across all infection sites. Conclusions: Elderly patients with LTCHI are more likely to harbor antimicrobial-resistant pathogens than those with CAIs. Careful consideration of LTCHI origin is therefore essential for empirical antibiotic selection and for strategies aimed at limiting further resistance. Full article

Using beneficial bacteria from the plant microbiome to combat pathogens is an environmentally friendly strategy for biological control. Although significant progress has been made in characterizing microorganisms with biocontrol potential, the optimal methods for applying such biological preparations to achieve maximum effectiveness against plant pathogens remain insufficiently defined. Our goal was to select rhizobacteria from the sugar beet microbiome and analyze their biocontrol capacity in both indirect and direct applications to protect the plant from Pseudomonas syringae pv. aptata P21. The methodological approach differed: indirect application involved seed priming with selected strains, Bacillus safensis MRh275, B. pseudomycoides JRh226, Stenotrophomonas maltophilia JRh266, or the T2 consortium (MRh275 and JRh266), while direct application involved simultaneous treatment of both the pathogen and the biocontrol strain. Although the direct approach resulted in a greater reduction in lesions and a lower concentration of H₂O₂, the indirect approach showed higher activity of peroxidase and superoxide dismutase as antioxidant enzymes, as well as phenylalanine ammonia-lyase, which is involved in the phenylpropanoid pathway and plant defense mechanisms. Infected plants showed higher expression of NPR1, MYC2, and LOX defense-related genes only under indirect biocontrol with all three strains, except in the T2 application. The T2 consortium performed best in direct biocontrol, where it most effectively reduced lesions. Since encounters between plants and pathogens cannot be accurately predicted, and the application of biological preparations should be easy and accessible for farmers, this study highlights the use of indirect biocontrol through seed priming to enhance the plant’s intrinsic defense capacity. Full article

Background: Periprosthetic joint infections (PJIs), a significant complication of total knee replacement surgery, are influenced by patient, surgeon, and healthcare system factors. Natural disasters can disrupt healthcare services and alter microbiological factors in the hospital environment. The impact of natural disasters on pathogen distribution in periprosthetic joint infection (PJI) is unclear. Therefore, this study investigated the association between the 2023 Kahramanmaraş-centered earthquakes in Türkiye and changes in microbiological patterns of PJI after knee arthroplasty. Methods: This retrospective cohort study included patients who developed PJI following total knee arthroplasty at the study center. The patients were divided into two groups based on the timing of their PJI diagnosis: pre-earthquake and post-earthquake. The demographic characteristics, comorbid diseases, and perioperative characteristics of each patient were recorded, and their microbiological profiles were analyzed. Logistic regression analysis examined the relationships between patient-related factors and causative agents. Results: 56 patients were studied and divided into two groups: 26 patients in the pre-earthquake group and 30 in the post-earthquake group. Furthermore, 79 bacterial isolates were obtained from these patients. Demographic, metabolic, and preoperative characteristics were similar between the two groups. No significant difference was found in the overall distribution of bacterial isolates. However, Gram-negative organisms, primarily Acinetobacter baumannii and Pseudomonas aeruginosa, increased in the isolate distribution after the earthquake. Patient analysis revealed that polymicrobial PJIs were significantly more frequent after the earthquake (56.7% vs. 23.1%; p = 0.011). Diabetes mellitus (DM) and smoking were associated with an increased risk of polymicrobial infection; the association was not statistically significant. Conclusions: In the post-earthquake period, patients who had undergone total knee arthroplasty and developed PJI showed a higher proportion of polymicrobial infections and a numerical increase in Gram-negative pathogens, along with more complex infection patterns compared to the pre-earthquake period. Although both patient groups demonstrated similar characteristics regarding patient-related and surgical factors, the observed changes indicate that the pressure on the healthcare system after a natural disaster can affect a hospital’s microbiological ecology. Identifying these indirect effects is crucial for guiding microbiological surveillance and infection control during post-disaster recovery periods, even for elective patients. Full article

Pseudomonas fluorescens is a rare, environmental Gram-negative bacterium that has been rarely reported as a cause of respiratory tract infections. This paper presents a case of a 72-year-old male who developed community-acquired pneumonia due to P. fluorescens. The diagnosis was made by sputum culture and he responded to meropenem treatment. A literature search revealed three previously reported cases of P. fluorescens pneumonia. These cases primarily affected elderly male patients. All reported patients demonstrated positive clinical outcomes following appropriate antimicrobial therapy. This case highlights that although P. fluorescens is often considered a colonizer, it may act as a potential pathogen in selected clinical settings. Full article

Nanotextured thin film metallic glasses (TFMGs) have emerged as promising antimicrobial coatings for biomedical applications; however, systematic comparisons across compositionally distinct Ti- and Zr-based systems, as well as their early-stage bactericidal mechanisms, remain limited. Here, we show, for the first time, a comparative, compositionally resolved correlation linking alloy chemistry, nanotexture, and bactericidal mechanisms across polymorphic TFMGs. Three co-sputtered biocompatible coatings (Ti₄₇Fe₄₁Cu₁₂, Zr₇₁Fe₃Al₂₆, and Zr₅₈W₃₁Cu₁₁) were deposited on medical-grade titanium and stainless steel (SS316L) via magnetron co-sputtering, producing uniform amorphous films (190–298 nm) with nanoscale roughness of 1.6 ± 0.05 to 8.1 ± 0.05 nm. Surface wettability spanned hydrophilic (71.1 ± 5.6°) to hydrophobic (106.5 ± 3.5°), modulating bacterial interactions. Antimicrobial performance against Pseudomonas aeruginosa was evaluated using live/dead fluorescence imaging, quantitative image analysis, and electron microscopy after 2–4 h incubation. All coatings reduced bacterial adhesion and viability relative to bare substrates, with Zr₅₈W₃₁Cu₁₁ achieving >60% reduction in surface-associated bacterial coverage. Time-resolved analysis revealed a rapid transition to predominantly non-viable populations on coated surfaces, in contrast to sustained viability on controls. Mechanistically, bactericidal activity arises from the synergistic coupling of nanotopography-induced membrane stress, wettability-governed adhesion energetics, and in situ formation of CuO, Fe₂O₃, WO₃, and ZrO₂ oxides that promote electrostatic interactions and proposed reactive oxygen species generation, driving oxidative membrane damage. These results establish a scalable design framework for TFMGs, while highlighting the need for long-term biofilm and electrochemical validation. Full article

According to an FAO report, the total area of saline-alkali land worldwide is approximately 954 million hectares, accounting for about 20% of global cultivated land. Saline-alkali stress significantly reduces soybean (Glycine max L.) yield and quality, and saline-alkali-tolerant plant growth-promoting bacteria (PGPB) have shown important application value for soybean planting in such farmlands. In this study, 15 strains of saline-alkali-tolerant bacteria were isolated from saline-alkali soil in Anda City, Heilongjiang Province, China, and identified morphologically, belonging to the genera Enterobacter, Bacillus, Chryseobacterium, Acinetobacter, Enterococcus, and Pseudomonas. Through tests for nitrogen fixation, phosphorus solubilization, potassium solubilization, hydrolase production (including pectinase, amylase, and protease), and germination promotion assays, Bacillus pumilus AD14 was identified as having the best growth-promoting effect on soybean seedlings. Pot experiments in saline-alkali soil showed that AD14 significantly promoted soybean seedling growth, increasing plant height by 5.63–6.37 cm and root length by 3.58–3.99 cm compared to the control. AD14 also enhanced saline-alkali tolerance by improving the activity of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and increasing soluble sugar and protein contents. Meanwhile, soil pH decreased by 10.94–12.15% and soluble salt content decreased by 9.59–13.39% after planting, and soil enzyme activities (including urease, sucrase, and catalase) increased markedly. These results demonstrate the great potential of AD14 for soybean planting in saline-alkali soil. This study provides a relevant reference for enriching the resources of saline-alkali-tolerant PGPB and developing new biological agents suitable for soybean planting in saline-alkali soils. Full article

Botrytis cinerea is a globally distributed phytopathogenic fungus that causes gray mold in eucalyptus seedlings, posing a severe threat to eucalyptus nursery production. Pseudomonas eucalypticola Liu et al. NP-1 is an endophytic bacterium isolated from eucalyptus with broad-spectrum antifungal activity. In this study, the fermentation broth extract of strain NP-1 was prepared using the organic solvent extraction method. The inhibitory effects, antifungal mechanisms, and biocontrol efficacy of the extract against B. cinerea were investigated. The results suggested that the NP-1 extract effectively inhibited mycelial growth, conidial germination, and germ tube development of B. cinerea. The EC₅₀ and EC₉₀ values for mycelial inhibition were 110 μg/mL and 332 μg/mL, respectively, while those for conidial germination inhibition were 126 μg/mL and 310 μg/mL. Microscopic and ultramicroscopic observations indicated that while the mycelial structures in the control and EC₅₀ groups remained intact, the EC₉₀ treatment significantly was associated with protoplasmic aggregation, leakage, and cavitation, suggesting potential structural damage to the fungal cells. In vitro and in vivo biocontrol assays showed that the control efficacy against gray mold reached 90.0% on detached eucalyptus leaves and 93.3% on eucalyptus seedlings. These findings elucidate the biocontrol potential of NP-1 and lay a foundation for the development of bio-based pesticides. Full article

Auranofin (AF), an FDA-approved drug for rheumatoid arthritis, exhibits strong antibacterial activity against Gram-positive bacteria, while Gram-negative species remain largely tolerant. This study assessed the antimicrobial activity of AF and three analogues against clinically relevant Gram-negative pathogens and explored tolerance mechanisms in Pseudomonas aeruginosa. Broth microdilution assays were performed on reference strains and clinical isolates of Escherichia coli, Klebsiella pneumoniae, and P. aeruginosa. Synergy studies with the most active analogue, PEt₃AuCl (AF-Cl), were conducted against P. aeruginosa using polymyxin B (PMB), two efflux-pump inhibitors, and two glutathione (GSH) depletors. Gold compounds showed MICs between 4 and >64 µg/mL, with AF-Cl displaying the highest activity. AF-Cl activity was markedly enhanced by PMB and efflux-pump inhibitors, indicating that outer membrane permeability and efflux contribute to tolerance. Additionally, GSH depletion significantly potentiated AF-Cl, implicating redox homeostasis in resistance. Overall, AF-Cl shows potential against Gram-negative bacteria when combined with agents targeting membrane integrity, efflux systems, or redox balance, supporting combinatorial strategies to overcome resistance in P. aeruginosa and related pathogens. Full article

Transient receptor potential ankyrin 1 (TRPA1) channels detect noxious cold and inflammatory mediators in mammals; yet their evolutionary origins and roles in neuro-immune integration remain unclear. Here, we investigated TRPA1 in Hydra vulgaris, an early metazoan with a simple nervous system, exposing polyps to noxious cold and Pseudomonas aeruginosa lysate. Using Western blotting, pharmacological modulation, and gene expression analyses, we demonstrated that TRPA1 mediates upregulation of nociceptive markers (Nrf2, NOS, SOD) and immune effectors (NF-κB, NOS, periculin, hydramacin). TRPA1 antagonism significantly reduced these responses, indicating its role as an amplifier of both nociceptive and innate immune signaling. These findings suggest that TRPA1-dependent coupling of nociceptive-like and immune responses is an ancient, conserved mechanism, providing insights into the molecular basis of integrated threat detection and offering potential avenues for targeting pain and inflammation-associated pathologies. Full article

Cystic fibrosis (CF) lung disease is characterized by chronic infection and progressive airway damage, driven by interactions between epithelial dysfunction, immune dysregulation, and microbial adaptation. Defective cystic fibrosis transmembrane conductance regulator (CFTR) function disrupts airway hydration and mucociliary clearance, creating a microenvironment that facilitates infection, particularly with Pseudomonas aeruginosa (P. aeruginosa). Within this environment, P. aeruginosa undergoes adaptive changes, including biofilm formation and metabolic reprogramming, which support long-term survival in the airway. Concurrently, host immune responses become dysregulated, with ineffective bacterial clearance and sustained neutrophil-dominated inflammation contributing to tissue injury. These processes establish a self-reinforcing cycle that drives disease progression. Importantly, early infection represents a critical therapeutic window during which bacterial populations remain more amenable to eradication before irreversible airway remodeling occurs. Delayed intervention promotes transition to a more treatment-refractory state and accelerates disease progression. Despite the clinical benefits of CFTR modulators, airway damage and established infections often remain. The relative contributions and interactions of epithelial dysfunction, immune dysregulation, and bacterial adaptation in sustaining chronic infection remain incompletely defined, representing a key knowledge gap. In this context, this review aims to integrate current evidence on host–pathogen co-adaptation in CF lung disease, with a particular focus on P. aeruginosa, and highlight emerging therapeutic strategies. Full article

Antibiotic resistance remains a major public health concern, particularly in regions with high rates of hospital- and community-acquired infections. This study aimed to quantify multidrug-resistant (MDR) bacterial strains in northern Mexico and to identify the most prevalent resistance phenotypes, the antibiotic classes with the highest resistance and susceptibility rates, the predominant MDR species, and the specimen types yielding the greatest number of isolates. Clinically relevant strains were collected from patients with confirmed infections. Microorganism identification and antimicrobial susceptibility test-ing were performed using the Vitek 2 Compact system (bioMérieux), and the results were analyzed descriptively. Of the 1544 strains analyzed, 761 (49.29%) exhibited multidrug resistance. Escherichia coli was the most frequently isolated MDR species, followed by Pseudomonas aeruginosa. Acinetobacter baumannii showed the highest resistance rate, with 95.55% of its strains classified as MDR, whereas P. aeruginosa had the lowest MDR proportion at 30.73%. These findings underscore the urgent need for rational antibiotic use and the development of new therapeutic agents, particularly those targeting Gram-negative bacilli, to mitigate the growing threat of antimicrobial resistance in this region. Full article

Ammonium nitrogen pollution presents a significant challenge in wastewater treatment. Traditional activated sludge processes often suffer from limitations such as low efficiency and high energy consumption when treating high-ammonium nitrogen wastewater. This study utilized previously screened high-efficiency heterotrophic nitrification aerobic denitrification (HN-AD) bacterial strains (Pseudomonas alcaliphila and Paracoccus versutus) synergistically with microalgae to construct an immobilized bacteria algae symbiotic system (IBAS). The nitrogen removal performance and microbial community response of the system were investigated under different nitrogen sources, carbon to nitrogen (C/N) ratios, and light intensities. Results demonstrated that the system achieved a removal rate of over 95% for nitrite and nitrate. Under conditions of C/N = 15 and high light intensity (335.36 μmol/(m² · s)), the removal rates of NH₄⁺-N, TN, and COD exceeded 90% without nitrite accumulation. Microbial community analysis revealed that high C/N conditions significantly enriched HN-AD functional bacteria (such as Acinetobacter) in the Pseudomonadota phylum and Gammaproteobacteria class. High light intensity promoted the proliferation of microalgae (Chlorella and Halochlorella), enhanced algal bacterial interaction, and improved system stability. This study elucidated the nitrogen removal mechanism of the IBAS under multi-factor regulation, providing a theoretical foundation and demonstrating application potential for low-carbon and high-efficiency wastewater treatment technologies. Full article

Background: Biofilm-associated urinary tract infections (UTIs) pose a significant therapeutic challenge due to the increased tolerance of biofilm-embedded bacteria to antimicrobial agents and the high risk of infection recurrence. The increasing prevalence of multidrug-resistant uropathogens necessitates the evaluation of alternative therapeutic strategies, including antibiotic combination therapy. This study aimed to assess the antibiofilm activity of selected antibiotics used individually and in combination against biofilms formed by clinically relevant uropathogens. Methods: Biofilms of Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Enterococcus faecalis isolated from patients with UTIs were developed on polystyrene microtiter plates and exposed to ciprofloxacin, nitrofurantoin, amikacin, and imipenem applied as monotherapy and in combinations. Biofilm biomass reduction was quantified spectrophotometrically using crystal violet staining and expressed as a percentage relative to untreated controls. Results: Antibiotic monotherapy produced moderate reductions in biofilm biomass, with efficacy dependent on bacterial species and antibiotic concentration. In contrast, antibiotic combinations demonstrated enhanced antibiofilm activity. The ciprofloxacin–nitrofurantoin combination showed increased biofilm biomass reduction compared with monotherapy against P. aeruginosa and E. coli. The imipenem–amikacin combination reduced P. mirabilis biofilm biomass by over 80%. Conclusions: These findings suggest that rationally selected antibiotic combinations may represent a more effective strategy than monotherapy for controlling biofilm-associated UTIs. Full article

The increasing demand for safer and environmentally sustainable products has intensified the search for natural alternatives to synthetic dyes. Filamentous fungi are promising sources of natural pigments due to their metabolic diversity and the feasibility of large-scale production. In this study, filamentous fungi isolated from Amazonian freshwater environments were evaluated for their potential to produce natural pigment-associated metabolites under different nutritional conditions. Forty-five fungal isolates were screened in solid media and subsequently cultivated in submerged fermentation using three media: potato dextrose broth supplemented with yeast extract (BD + YE); malt extract broth (ME); and yeast extract–sucrose broth supplemented with magnesium sulfate (YES). Among the 39 pigment-producing isolates, seven were selected for further investigation. Sucrose favored the highest absorbance values of pigment extracts, particularly for isolates identified as Talaromyces amestolkiae. In addition, the extract of T. amestolkiae TA10P5-3 exhibited the highest absorbance value (6.83 abs. units at 400 nm) when cultivated in YES medium, indicating stronger chromophore-associated spectral signals. This extract also showed antimicrobial activity against Pseudomonas aeruginosa (625 μg/mL), Staphylococcus epidermidis (312 μg/mL), and Candida tropicalis (625 μg/mL). Finally, the TA10P5-3 extract presented high total phenolic content (246.30 mg GAE/g) and antioxidant activity (EC₅₀ = 5470 μg/mL). These findings highlight Amazonian freshwater fungi as promising sources of natural pigments with potential industrial applications. Full article