Search Results (939)

This decade-long surveillance study (2016–2025) investigates the acquisition of multidrug-resistant (MDR) bacteria in South Atlantic cetaceans to evaluate how ecological niches modulate exposure to biological pollution. Analyzing clinical isolates from stranded cetacean carcasses (n = 346), we used Generalized Linear Mixed-Effects Models (GLMMs) to mitigate multi-center analytical biases and compare resistance profiles across coastal and oceanic species. We observed a significant, progressive upward trend in the overall MDR probability over the decade. Although raw MDR was higher in the demersal-feeding Pontoporia blainvillei (58.2%) than in the sympatric, water-column-foraging Sotalia guianensis (22.0%), multivariate modeling revealed that this difference was primarily driven by the geographic stranding location rather than by intrinsic foraging ecology. High gastrointestinal MDR (73.9%) suggests dietary intake as a primary biological gateway. Demographic modeling revealed a significant sex-based association in P. blainvillei, with females facing a higher risk (p = 0.009), although the specific ecological or physiological mechanisms underlying this difference remain unknown. High MDR rates in deep-diving Lagenodelphis hosei (70.8%) and Kogia breviceps (67.9%) suggest that resistant pathogens may reach bathypelagic food webs, potentially via vertical trophic pathways. These findings suggest that spatial environmental contamination, alongside foraging and reproductive ecologies, is a key driver of exposure to the anthropogenic resistome. Because carcass-based sampling inherently targets a diseased or senescent fraction, these high prevalences may overestimate the resistome burden of healthy free-ranging populations. The detection of human pathogens across coastal and offshore habitats indicates persistent deficiencies in terrestrial effluent management, reinforcing cetaceans as One Health sentinels. Full article

The Blattella germanica L. (Blattodea: Ectobiidae) is a major urban pest with widespread insecticide resistance. This study evaluated the synergistic effect of combining Metarhizium anisopliae with beta-cypermethrin (β-CYP) and investigated its mechanisms. Compatibility assays showed that β-CYP (1–10 μg/mL) was highly compatible with M. anisopliae (1 × 10⁷–1 × 10⁹ cfu/mL), with enhanced compatibility at lower concentrations. Bioassays confirmed significant synergy, increasing mortality and shortening median lethal time. Mechanistically, the combination accelerated histopathological damage to the midgut, hindgut, Malpighian tubules, and fat body, while promoting fungal proliferation in hemolymph and gut tissues. 16S rRNA sequencing revealed gut microbiota dysbiosis: Firmicutes replaced Bacteroidetes as the dominant phylum, opportunistic pathogens (Weissella, Alistipes) increased, and beneficial bacteria (Enterococcus, Fusobacterium) decreased. Weissella recolonization experiments confirmed its mortality-enhancing role. Additionally, the combination suppressed carboxylesterase activity and modulated immune gene expression (CYP4G19, BgPo), compromising host defense. Collectively, these findings demonstrate that β-CYP and M. anisopliae exert synergistic effects through multi-target mechanisms, offering a promising integrated pest management strategy that reduces chemical usage while enhancing biocontrol efficacy. Full article

Background/Objectives: Surveillance of local antibiotic resistance plays a critical role in guiding empirical antibiotic therapies in emergency departments (EDs). This study aimed to collect and analyze a five-year period of prevalence and AMR rates among “ESKAPE” pathogens in a tertiary-care ED setting. Methods: This retrospective observational study included a complete census of microbiological specimens collected from patients presenting to the emergency department between 1 January 2019 and 31 December 2023. Data was retrieved from the MedBakter laboratory information system. Non relevant isolated and duplications were excluded. Only the first isolates per patient per phenotype were included in the final dataset. Results: The final dataset contained 6510 isolates. The most frequent isolates were E. coli (2717, 41.7%), K. pneumoniae (715, 11.0%), and P. mirabilis (696, 10.7%) followed by E. faecalis (662, 10.2%). Prevalence of multi-drug resistance (MDR) was 23.26% among “ESKAPE” pathogens, with highest prevalence in M. morganii (79.6%), P. stuartii (78.5%) and S. marcescens (77.1%). Difficult-to-treat resistance (DTR) was found in 32 isolates, while extensive drug resistance (XDR) was found in 5 isolates. The prevalence of other high-priority MDR bacteria was 12.4% for MRSA and 4.7% for VRE, while among Gram-negative bacteria the prevalence of carbapenem-resistant Enterobacterales was 0.52%. The prevalence of cephalosporin-resistant Enterobacterales varied greatly between 0 and 33%. Conclusions: Despite these important AMR trends, the cumulative antibiogram, according to the World Health Organization (WHO)-issued Access, Watch and Reserve (AWaRe) classification, revealed room for empirical antibiotic choices that spare Watch and Reserve agents. The results will aid the revision of the local antibiotic guidelines. Full article

Objectives: The escalation of multidrug-resistant (MDR) clinically relevant bacterial isolates, including Escherichia coli and key ESKAPE pathogens, represents a critical global healthcare threat. While antimicrobial peptides (AMPs) offer promising alternatives, metabolic instability often limits their clinical use. This study investigated the therapeutic potential, antimicrobial efficacy, and resistance dynamics of peptide D-TN6 against highly resistant bacterial strains. Methods: D-TN6 efficacy was evaluated against 164 clinical isolates, including pan-drug-resistant, carbapenem-resistant, and polymyxin-resistant phenotypes. A 20-passage serial induction assay compared resistance development kinetics of D-TN6 against gentamicin over an extended period. Results: D-TN6 demonstrated potent efficacy against MRSA (minimum inhibitory concentration (MIC)₉₀: 1 µg/mL) and remained effective against polymyxin B-resistant Klebsiella pneumoniae (MIC₉₀: 8 µg/mL) and pan-drug-resistant Acinetobacter baumannii (MIC₉₀: 8 µg/mL). In resistance assays, while the gentamicin MIC increased 256-fold by the 17th passage, the D-TN6 MIC remained constant at 1 µg/mL throughout the 20-passage study. Conclusions: These findings underscore D-TN6 as a robust therapeutic candidate. Its efficacy against MDR strains and its feature of low propensity for resistance development—likely due to membrane disruption—position D-TN6 as a promising solution for life-threatening infections where conventional last-resort agents fail. Full article

Precision nutrigenomics requires a diet–microbiome–host perspective because microorganisms can transform feed substrates, generate bioactive metabolites, compete with pathogens, and modify intestinal and systemic gene regulation. This structured narrative review synthesizes representative controlled feeding trials, transcriptomic and targeted gene-expression studies, microbiome analyses, and complementary multi-omic evidence concerning dietary regulations in cultured finfish. The available evidence is concentrated particularly on soybean-derived proteins, lipid-source replacements, selected amino acids and micronutrients, functional additives, probiotics, and fermented ingredients in a limited range of cultured finfish species; therefore, the synthesis is not intended to provide exhaustive coverage of every dietary intervention or finfish taxon. Recurrent host responses involve intestinal inflammation and barrier integrity, nutrient transport, lipid and bile-acid metabolism, long-chain polyunsaturated fatty-acid biosynthesis, targets of rapamycin/insulin-like growth factor (TOR/IGF) signaling, and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) antioxidant defense. The expanded microorganism-centered synthesis shows that dietary effects depend on microbial niche, substrate availability, community succession, metabolite production, and strain-specific probiotic or pathobiont activity. Lactic-acid bacteria, Bacillus-associated interventions, butyrate-generating strategies, fermented ingredients, and microbial biomass may support digestion, immune balance, and disease resistance, but taxonomic shifts alone do not demonstrate functional benefit. Current evidence is limited by extensive reliance on 16S ribosomal RNA (16S rRNA) relative-abundance data, inconsistent digesta-versus-mucosa sampling, inadequate feed and water controls, and weak causal validation. Future precision aquafeed studies should combine host transcriptomics with absolute microbial quantification, shotgun metagenomics, metatranscriptomics, metabolomics, culturomics, histology, and pathogen challenge. Integrating microbial function with host phenotype can improve sustainable feed design, intestinal health, and resilience. Full article

Pseudomonas aeruginosa poses major public health threats, due to its robust, treatment-resistant biofilms, which contribute to multi-drug resistance. Bacteriophages offer a promising alternative. This study evaluates giant Phikzvirus and conventional Pbunavirus phages against pre-formed biofilms from four multi-drug-resistant P. aeruginosa clinical isolates. We tested six phages (three Phikzvirus, three Pbunavirus) against four clinical strains, isolated from chronic urological and pulmonary infections (Ur1, Ur14, Lu3, Lu9) at MOIs 0.001–0.1, quantifying biofilm biomass by crystal violet and visualizing architecture by SEM. Phage treatment leads to significant disrupted biofilms in three isolates achieving more than 50% reduction—comparable with typical antibiotic efficacy against mature biofilms. All biofilms retained their EPS architecture after the treatment, as revealed by SEM, suggesting that residual eDNA-polysaccharide complexes could maintain structural cohesion even after bacterial lysis. The phage’s ability to reduce biofilm biomass demonstrated a significant dependence on the multiplicity of infection (MOI). The best results of anti-biofilm activity of phages (reduction in biofilm biomass by more than 75%) were observed for the phage phiKZ for two strains—Ur1 at MOI = 0.001 and Lu9 at MOI = 0.01—and for the phage phi14/1 for the Ur1 strain at MOI = 0.001. The biofilm formed by the antibiotic-resistant clinical isolate Ur14 demonstrated exceptional resistance to both types of bacteriophages despite the sensitivity of bacteria of this strain to the studied phages. This highlights the need for personalized phage therapy, where tailored phage cocktails are selected for each specific bacterial strain to achieve optimal destruction of the biofilm. Full article

Antimicrobial peptides (AMPs) are promising alternatives to antibiotics for combating multidrug-resistant bacteria, yet their practical application is hindered by the low content of natural AMPs and the high cost of chemical synthesis. In this study, we developed a high-efficiency heterologous expression system for the proline-rich cationic antimicrobial peptide Api137 in Saccharomyces cerevisiae CENPK2 by engineering the Ty retrotransposon system composed of multi-locus integration. Recombinant plasmids carrying Api137 encoding elements were constructed and integrated into the CENPK2 genome, generating the engineered strain CENPK2 + Ty1-2/2/3/4. The target fusion peptide (5.2 kDa) was successfully expressed and identified by Tris-tricine-SDS-PAGE and liquid chromatography–tandem mass spectrometry (LC-MS/MS). The quantification of Api137 from fermentation broth was applied by high-performance liquid chromatography (HPLC) which showed that the yield of tandem peptide in the fermentation supernatant reached 20.5 mg/L and the intracellular retention rate was 33.0%. Comparative analysis of MIC and MBC values revealed that the biologically synthesized Api137 exhibited slightly superior antibacterial activity relative to the chemically synthesized Api137. In vitro functional assays demonstrated that the fermentation supernatant of the engineered strain exhibited broad-spectrum antibacterial activity against five pathogenic bacteria, with a maximum antibacterial rate of 92.9% against Aeromonas veronii. Hemolysis assays and cytotoxicity tests confirmed that the fermentation supernatant exhibited neither hemolytic activity nor cytotoxicity. Moreover, the expression of Api137 did not impose a metabolic burden on the host. This study establishes a Ty transposon-mediated strategy for the high-level expression of Api137 in S. cerevisiae, which significantly demonstrates the antibacterial activity of Api137 while ensuring excellent biosafety. Full article

Gamma (γ)-aminobutyric acid (GABA) is a non-proteinogenic amino acid recognized for its primary function as the main inhibitory neurotransmitter in the mammalian central nervous system and its role as a stress-responsive metabolite in various microorganisms. This review critically examines the biosynthesis of GABA by lactic acid bacteria (LAB) via the glutamate decarboxylase (GAD) system and evaluates its potential applications in food and health sectors. The mechanistic details of the GAD pathway are analyzed, focusing on the integrated roles of gadA/gadB decarboxylases, the gadC antiporter, and pyridoxal−5′-phosphate (PLP) dependency in relation to acid resistance, metabolic flux, and strain variability. Taxonomic and strain-level diversity among GABA-producing LAB is assessed, with emphasis on the highly strain-specific nature of GABA production rather than broad species or genus generalizations. Fermentation optimization parameters (pH, temperature, substrate loading, and cofactor management) and scale-up challenges, including techno-economic feasibility and downstream recovery efficiency, are critically evaluated. Integration of LAB-derived GABA into fermented food matrices is discussed with attention to sensory compromises, stability, regulatory factors, and clean-label considerations. Evidence from clinical and preclinical studies is synthesized to assess the physiological significance of dietary GABA, distinguishing between purified GABA supplementation, GABA-enriched fermented foods, and probiotic effects of live LAB, while addressing the GABA paradox and gut–brain axis interactions. Significant research gaps are identified, including the need for standardized quantification methodologies, multi-omics-guided strain engineering, predictive bioprocess modeling, and rigorously designed human trials in realistic food matrices. This review provides a systems-oriented, critical framework to promote scalable and evidence-based advancement of GABA-enriched functional foods. Full article

Background: Wound infections are common sequelae of wound treatment in horses. Secondary bacterial colonization with antimicrobial resistant microorganisms is of particular concern and is of crucial importance regarding the “One Health Concept”. Due to frequent antimicrobial resistance (AMR), conventional treatments often involve determining resistance and sensitivity using time-consuming antibiograms. Infections with multi-resistant pathogens are especially challenging. This case series presents studies of four horses evaluating the efficacy of Cold Atmospheric Plasma-Aerosol (CAP-A) as a standalone treatment for equine wound infections. Methods: A sampling unit of horses aged 5 weeks to 11 years presented with various infected wounds which were treated with CAP-A. Treatment was administered once daily for up to two months; each session consisted of 2 × 3 min nebulization cycles. Following 10 days of treatment, methicillin-resistant Staphylococcus aureus (MRSA) was no longer culturally detectable, and advanced wound healing was observed. Microbiological samples were collected before and after the treatment period, and the antibiotic resistance of pathogens was determined. Photographs were used to document wound progression and healing process. Results: Antibiograms and microbiological examinations identified several multi-resistant bacteria in all horses. CAP-A treatment decreased microbial load of pathogenic flora and removed MRSA without the use of antibiotics. Conclusions: CAP-A therapy demonstrated promising results as a non-pharmacological treatment option for equine wound infections with multi-resistant bacteria such as MRSA and multi-resistant Gram-negative bacteria, achieving both clinical and microbiological improvement. Horses tolerated sessions without any signs of discomfort. Further research should be based on a clinical follow-up as part of a prospective study with a larger sample size and negative control to draw definite conclusions about the efficacy of the treatment. Full article

Colistin (polymyxin E), a last-resort antibiotic for the treatment of multidrug-resistant Gram-negative bacterial infections, is becoming increasingly compromised by the rapid emergence and dissemination of resistance. The extensive use of colistin in agriculture and veterinary medicine has accelerated the spread of plasmid-mediated mobile colistin resistance (mcr) genes, facilitating transmission across human, animal, and environmental reservoirs. This review provides a comprehensive overview of the epidemiology, molecular mechanisms, and geographical distribution of colistin resistance in the Middle East and North Africa (MENA) region. Analysis of the available literature indicates that Tunisia reports the highest prevalence of colistin-resistant Gram-negative bacteria in North Africa (58.09%), followed by Egypt (24.76%), Algeria (14.29%), and Libya (2.86%). Across the region, mcr-1 is the predominant plasmid-mediated resistance determinant, whereas chromosomal alterations involving the mgrB, pmrA/pmrB, and phoP/phoQ regulatory systems are the principal non-plasmid-mediated mechanisms. Resistance has been documented in major clinical pathogens, including Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, as well as in livestock, poultry, aquaculture, wildlife, food products, and environmental samples, highlighting the interconnected nature of resistance transmission under a One Health framework. The evidence demonstrates substantial geographical variability and significant gaps in surveillance across several MENA countries, limiting accurate regional burden estimates. Strengthening antimicrobial stewardship, harmonized surveillance programs, molecular monitoring of resistance determinants, and the implementation of One Health strategies are essential to limit the continued emergence and dissemination of colistin resistance throughout the region. Full article

With the rapid expansion of intensive aquaculture, the frequent outbreak of diseases and the overuse of antibiotics have become increasingly critical issues. Therefore, developing green and efficient antibiotic alternatives is essential for the sustainable growth of the industry. As a novel probiotic, Bacillus velezensis has shown great potential in improving the disease resistance of aquatic animals, owing to its excellent spore-forming ability, broad-spectrum antibacterial activity, and immunoregulatory functions. This paper systematically reviews the main mechanisms by which B. velezensis enhances disease resistance in aquatic animals, including directly inhibiting pathogens through the secretion of various lipopeptides and polyketides such as surfactin, iturin, and fengycin; interfering with pathogen quorum sensing systems via quorum quenching enzymes, thereby suppressing virulence factor expression and biofilm formation; modulating intestinal microbiota structure to increase the abundance of beneficial bacteria while reducing pathogenic proliferation; and activating the non-specific immune system of the host to upregulate immune-related indicators such as acid phosphatase, superoxide dismutase, and key cytokines (such as IL-1β, TNF-α). In addition, this review summarizes the application effects of B. velezensis on improving aquaculture water quality and promoting host growth. Furthermore, the potential ecological impacts on natural microbial communities and strain-dependent biosafety risks are evaluated. Finally, current research limitations—such as strain-specific functional differences, insufficient in-depth analysis of mechanisms, and inconsistent application outcomes—are discussed. Future prospects for promoting the efficient and stable application of B. velezensis in aquaculture through strategies including gene editing, multi-omics integration, and precise formulation compounding are also proposed. Full article

Background: Gram-negative bacteria resistant to multiple drugs are a major cause of illness and death worldwide. Their remarkable capacity to develop resistance to antibiotics makes them a serious concern in medical practice. Methods: A simple, green, novel method is used to synthesize ZnO nanoparticles (ZnO NPs) using ethanolic extracts of Diplazium esculentum via precipitation. Results: ZnO NPs exhibit a hexagonal structure with a particle size of ~30 nm and a band gap of 3.24 eV. The defect sites formed in ZnO NPs were estimated using prominent peaks in the photoluminescence spectra. ZnO NPs displayed a more than 4-log reduction in multi-drug-resistant E. coli and K. pneumoniae clinical isolates at a 500 μg/mL concentration. Moreover, ZnO NPs significantly reduced the biofilm bacterial cell viability of clinical isolates of Gram-negative bacteria. Complete eradication of biofilms was achieved for drug-resistant E. coli clinical isolates using a combination of sub-MIC of gentamicin and 500 μg/mL ZnO NPs. Green-synthesized ZnO NPs did not induce oxidative stress in mice, as indicated by unchanged GST, GSH, and thiol levels across all the tested organs. ZnO NPs showed both antibacterial and antibiofilm efficacy against drug-resistant strains of E. coli, K. pneumoniae, and S. aureus and completely eradicated E. coli biofilm in combination with gentamicin. Conclusions: Our study focuses on the sustainable synthesis of biocompatible ZnO NPs for the treatment of infections caused by pathogens belonging to the high-priority ESKAPE group. Full article

Metabolic syndrome (MetS) is a complex and heterogeneous condition characterized by the coexistence of obesity, type 2 diabetes mellitus (T2DM), hypertension, chronic low-grade inflammation, and metabolic dysfunction. Increasing evidence suggests that the gut microbiota plays a central role in the development and progression of MetS by influencing host metabolism, intestinal barrier integrity, immune activation, endocrine signaling, and vascular homeostasis. This narrative review summarizes current evidence regarding gut microbiota alterations across major obesity-related metabolic phenotypes, including obesity alone, obesity complicated by T2DM, and obesity associated with hypertension. Obesity is generally characterized by reduced microbial diversity, depletion of beneficial taxa such as Faecalibacteriumprausnitzii and Akkermansia muciniphila, impaired short-chain fatty acid (SCFA) signaling, increased intestinal permeability, and metabolic endotoxemia. The coexistence of T2DM is associated with a more pronounced depletion of butyrate-producing bacteria, altered bile acid metabolism, impaired incretin signaling, and enhanced inflammatory activation that may contribute to insulin resistance and hyperglycemia. In hypertensive obesity, gut dysbiosis appears to preferentially involve disturbances within the gut–vascular axis, including reduced SCFA-producing taxa, increased trimethylamine N-oxide production, endothelial dysfunction, oxidative stress, and vascular inflammation. Although microbial signatures partially overlap among metabolic phenotypes, functional alterations in microbial metabolites and host–microbiota interactions may better explain disease heterogeneity than isolated taxonomic changes. Current evidence supports the potential role of microbiota-targeted interventions and integrated multi-omics approaches in future precision medicine strategies for cardiometabolic disease prevention and management. Full article

Background/Objectives: Antibiotic resistance in bacteria poses a major health problem worldwide. Therefore, to counteract this life-threatening problem, we sought to investigate in the present study the possible potentiation of the efficacy of amoxicillin (AMX) and clavulanic acid (CA) by 1,8-cineole (CN), a candidate resistance-modulating agent. The approach seeks to investigate, in vitro and in silico, the interactions among these three molecules. Methods: The antibacterial activity was determined against resistant Escherichia coli (E. coli) using microdilution methods, synergy tests, and time-kill assays for AMX, CA, and CN, used either separately or in combinations: AMX–CA, AMX–CN, CA–CN, and AMX–CA–CN. Furthermore, an in silico drug design methodology was employed, utilizing an integrated workflow that combines Density Functional Theory (DFT) for ligand optimization with molecular docking simulations to evaluate binding energies and interactions between the penicillin-binding protein (PBP) and ligands. Results: In vitro synergy experiments and time-kill assays revealed substantial antibacterial efficacy of the AMX–CA–CN combination. In silico analyses, performed under the simplifying assumption of a pre-assembled multi-ligand entity, were consistent with these findings: within our docking model, the AMX–CA–CN combination exhibited the most favorable computed binding affinity to a representative penicillin-binding protein (PBP3, PDB 7ONW). Conclusions: 1,8-cineole can potentiate the antibacterial effects of AMX–CA, indicating that the AMX–CA–CN combination warrants further evaluation as a candidate adjunctive strategy against ESBL-producing E. coli. Full article

Background: Multi-drug resistant Gram-negative bacteria (GNB) are major contributors to the antimicrobial resistance (AMR) burden. AMR mechanisms are primarily mediated by proteoforms; therefore, proteomic analyses of GNB offers a significant advantage in understanding the mechanisms of AMR. A large portion of these mechanisms are mediated by membrane proteins; however, they are often difficult to extract due to their hydrophobic nature and complex interactions with other components of the cell membrane. To extract the greatest number of proteoforms, an efficient homogenisation protocol is required to effectively disrupt the rigid cell wall and membrane. Methods: Using Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, we systematically compared the extraction efficiency of bead-beating with flash frozen and lyophilized cell pellets. Results: We demonstrate that lyophilization improves bead-beating extraction methods by increasing the detection of membrane proteins. We detected numerous unique membrane proteins in each bacterial isolate, including ABC transporters and proteins involved in lipopolysaccharide synthesis, when lyophilizing prior to bead-beating, compared to only flash-freezing. Conclusions: As membrane proteins play a central role in AMR mechanisms, this improvement in their isolation and identification will aid in understanding the resistance and molecular mechanisms associated with multi-drug resistant GNB. Full article