Search Results (6,774)

Background/Objectives: Gram-negative neonatal sepsis remains a cause of morbidity and mortality in preterm infants, yet the relationship between early clinical severity and long-term neurodevelopmental outcomes is incompletely defined. This study aimed to characterize Gram-negative sepsis in preterm infants and to evaluate its short-term and 18–24-month neurodevelopmental consequences. Methods: We conducted a retrospective observational cohort study of preterm infants admitted to a tertiary neonatal intensive care unit between 1 January 2022 and 31 December 2023. Infants with culture-proven Gram-negative neonatal sepsis, including both early-onset sepsis (EOS) and late-onset sepsis (LOS), were included. Clinical, microbiological, therapeutic, and laboratory data were collected, and survivors were assessed at 18–24 months’ corrected age using the Bayley Scales of Infant and Toddler Development. Results: Among infants with culture-proven Gram-negative sepsis, late-onset cases were more frequent than early-onset cases, and Klebsiella pneumoniae was the most common pathogen (38.0%). Multidrug-resistant organisms were associated with 52.0% of infections. In-hospital mortality was 26.0%. Major short-term complications included intraventricular hemorrhage (24.0%), severe intraventricular hemorrhage (20.0%), necrotizing enterocolitis (12.0%), bronchopulmonary dysplasia (20.0%), and meningitis (10.0%). Among survivors who underwent neurodevelopmental assessment, neurodevelopmental impairment was observed in 38.0%, most frequently affecting the language (22.5%) and cognitive (20.0%) domains. Infants with neurodevelopmental impairment had significantly lower gestational age and birth weight and higher inflammatory biomarker levels. In multivariable analyses, lower gestational age emerged as the strongest independent predictor of both mortality (adjusted OR 0.19, 95% CI 0.04–0.99) and neurodevelopmental impairment (adjusted OR 0.12, 95% CI 0.02–0.71). Conclusions: Gram-negative neonatal sepsis in preterm infants was associated with substantial mortality, severe neonatal complications, and a high burden of later neurodevelopmental impairment. Lower gestational age was independently associated with adverse short- and long-term outcomes. These findings support early recognition, targeted antimicrobial therapy, and structured neurodevelopmental follow-up in this high-risk population. Full article

Clonal hematopoiesis of indeterminate potential (CHIP) and the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) are both linked to NLRP3-mediated cardiovascular inflammation, but their interaction has not previously been explored. This work proposes the CHIDT axis (clonal hematopoiesis–dysbiosis–TMAO), a feed-forward mechanism in which TET2 loss-of-function CHIP- and TMAO-generating Gram-negative gut dysbiosis mutually enhance cardiovascular risk. The model proceeds in three nodes. CHIP-associated intestinal immune dysregulation promotes luminal expansion of Gammaproteobacteria, which produce both trimethylamine via CntA/CntB-mediated L-carnitine oxidation and ADP-heptose as an obligate LPS biosynthetic intermediate. TMAO amplifies NLRP3 inflammasome activation through the SIRT3 → SOD2 → mtROS pathway. The evidence base of the CHIDT model is strongest for TET2-CHIP; the proposed extension to DNMT3A-CHIP rests on indirect, associative data and requires dedicated experimental confirmation before it can be considered established. TXNIP cascade, with predicted disproportionate potency in macrophages epigenetically primed by TET2 haploinsufficiency. High concentrations of TMAO have also been shown to suppress TET2 expression in endothelial cells through CYTB promoter hypermethylation, inducing NLRP3–GSDMD-dependent pyroptosis, although it remains unclear whether physiological TMAO levels can trigger this effect. Concurrently, ADP-heptose activates the ALPK1–TIFA–NF-κB pathway in bone marrow progenitors, favoring the expansion of mutant hematopoietic stem and progenitor cells. The model identifies three potential therapeutic strategies: NLRP3 inhibition, microbial TMA lyase inhibition, and microbiome-targeted reduction in Gram-negative bacteria. None has been tested in CHIP carriers stratified by plasma TMAO. Further studies in preclinical models and human cohorts integrating CHIP genotyping and TMAO quantification are needed to validate the CHIDT axis as a target for precision cardiovascular prevention. Full article

The rapid hemostasis of deep and irregular wounds is of great clinical significance. In this study, an injectable hemostatic hydrogel based on bioorthogonal conjugation was developed. This gel uses thrombin (TMB) as the hemostatic active substance and 4ARM-PEG-N₃ as the crosslinking agent, which undergo orthogonal conjugation via the classic azide–alkyne click reaction to form an injectable hydrogel (TMB-PEG). The resulting hydrogel exhibited a transparent, injectable gel state. TEM images revealed that the hydrogel comprised sheet-like structures and interwoven fibers with a diameter of approximately 100 nanometers. In a puncture bleeding wound model, hemostasis with the TMB-PEG hydrogel required only 25 s, with a blood loss of 1.9 ± 1.3 mg, both approximately one-sixth of that of the control group. Moreover, the hemostatic performance of the TMB-PEG hydrogel was far superior to that of three other commonly used hemostatic materials. Furthermore, cephalosporin antibiotics were conjugated to the hemostatic gel via orthogonal reactions, endowing it with significant broad-spectrum antibacterial activity, achieving over 99% antibacterial efficacy against both Gram-negative and Gram-positive bacteria. Full article

Antimicrobial resistance (AMR) is a growing global public health challenge. Its development is strongly associated with the inappropriate and excessive use of antimicrobial agents, leading to reduced treatment effectiveness, limited availability of therapeutic options, constraints on medical procedures, and an increasing economic burden. This narrative review synthesizes current knowledge on antibiotic-resistant bacteria detected in airborne samples from healthcare environments and examines their reported resistance profiles. The review focused on the bacterial species identified, methods used for antimicrobial susceptibility assessment, types of healthcare facilities investigated, and environmental and behavioral factors influencing the occurrence and dissemination of airborne antibiotic-resistant bacteria. The clinical relevance of the reported pathogens was discussed in the context of the WHO Bacterial Priority Pathogens List (BPPL), while the WHO AWaRe classification and TrACSS framework were used as complementary interpretative tools to contextualize resistance patterns and their implications for antimicrobial stewardship and AMR surveillance. The reviewed studies showed that airborne bacterial communities in healthcare settings were dominated by Gram-positive bacteria, particularly Staphylococcus spp. and Bacillus spp., while clinically relevant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Acinetobacter baumannii were also frequently detected. Resistance to β-lactam antibiotics was the most frequently reported resistance pattern. Considerable heterogeneity in sampling strategies, antimicrobial susceptibility testing methods, and interpretive criteria limited direct comparison among studies. The findings highlight the need for standardized monitoring methods, long-term surveillance, and integrated environmental and clinical research to support infection prevention strategies and mitigate antimicrobial resistance. Full article

Orchid plants, due to their high aesthetic qualities of large inflorescences, long flowering period, and ease of care, have high commercial potential; however, when grown industrially in factories, they are susceptible to infectious diseases. In this study, we isolated from Phalaenopsis spp. plants epiphytic, rhizospheric, and endophytic bacteria associated with soft rot symptoms. Twenty-nine isolates exhibiting pectolytic activity were identified as strains of the genera Bacillus, Klebsiella, Microbacterium, Paenibacillus, Paracidovorax, Pseudomonas, and Psychrobacillus based on 16S rRNA analysis. These isolates were tested for their ability to produce cellulase, amylase, sucrase, proteinase, and lipase; to form biofilms; and to exhibit motility (swimming and swarming). Potato microplants under in vitro conditions were used as a model object for initial screening of the strains’ potential phytotoxicity. Most strains were shown to inhibit plant growth, particularly root development. Injection of suspensions of these strains into orchid leaves caused symptoms of soft rot. Thus, we isolated Gram-positive bacteria for the first time from orchid tissues with soft rot symptoms and demonstrated an association of these strains with plant tissue maceration in potato and orchids. Gram-positive bacteria with pectolytic activity are not typical pathogens of orchid soft rot and may require changes in approaches to the monitoring of phytopathogens for this group of plants. Full article

Uterine infections (metritis and endometritis) are a leading cause of culling and reproductive failure in transition dairy cows, and antibiotic-resistant Gram-negative pathogens limit conventional therapy. This randomized, controlled, multi-farm field trial evaluated whether four intravaginal infusions of a host-adapted lactic acid bacteria (LAB) cocktail (Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, P. acidilactici FUA3140; 10⁸–10⁹ cfu/dose) at −3, −2, +3, and +4 weeks relative to calving reduce periparturient disease and improve milk production. A total of 526 pregnant cows (426 Holstein, 100 Jersey) from four commercial Alberta farms (automatic-milking, parlor, and certified-organic systems) were block-randomized within farm and parity to TRT1 (saline; n = 175), TRT2 (saline + skim milk; n = 176), or TRT3 (LAB cocktail in saline + skim milk; n = 175). Uterine infection incidence was assessed by Metricheck™ mucus scoring and transrectal ultrasonography at +3 and +4 weeks postpartum. Across the principal peripartum infectious outcomes, TRT3 showed a consistent protective effect: uterine infection incidence was lowest in TRT3 (18.8% vs. 25.1% in pooled controls; OR = 0.69; 95% CI, 0.44–1.09; an approximately 25% relative reduction; exact p = 0.12), and this metritis signal was additionally supported by a repeated-measures mixed model accounting for farm, parity, and week (p = 0.0175), although the Bonferroni-adjusted pairwise contrasts were tendencies (adjusted p ≈ 0.12), and the effect did not differ by parity (treatment × lactation interaction, p = 0.97). Subclinical mastitis was numerically lower in TRT3 than in pooled controls (5.3% vs. 8.9%; OR = 0.57; 95% CI, 0.27–1.24; exact p = 0.16), whereas retained placenta, milk fever, displaced abomasum, and lameness showed no clear cow-level treatment effect in the cow-level exact analyses. Milk yield increased significantly in multiparous cows, which produced 4.6 L/day more milk than TRT1 and 3.22 L/day more than TRT2 over the first 50 days in milk (p < 0.01 for both contrasts; treatment × parity interaction, p = 0.01). No effect was seen on milk composition, uterine involution, or reproductive performance. The trial supports intravaginal LAB as a candidate antibiotic-free prophylactic whose response depends on farm- and cow-level contexts and whose mechanisms require confirmation through microbiological and metabolic measurements. Full article

Background: Essential oils (EOs) are promising natural antimicrobials against food-borne pathogens, yet their efficacy depends on complex chemical profiles that vary by species and origin. The evaluation of underexplored aromatic plants from the Peruvian Amazon may reveal novel bioactive agents. Methods: We chemically characterized six EOs from Aloysia citrodora, Arracacia xanthorrhiza (two cultivars), Baccharis genistelloides, Piper acutifolium, and Piper lanceifolium using GC-MS and assessed their antibacterial activity against Escherichia coli (ATCC 25922), Salmonella enterica (ATCC 14028), Enterococcus faecalis (ATCC 29212), and Staphylococcus aureus (ATCC 49476). Results: EOs of Aloysia citrodora and Arracacia xanthorrhiza cv. Yellow exhibited the strongest inhibition, effective against both Gram-positive and Gram-negative bacteria, potentially associated with higher relative abundances of oxygenated monoterpenes and aliphatic aldehydes. Dose–response analysis supported their superior antibacterial potency, with the lowest LD₅₀ values observed for these oils. Oils rich in sesquiterpenes showed lower activity. Conclusions: These findings underscore the importance of EO chemical composition for antibacterial potency and suggest that select Amazonian EOs have potential as natural preservatives for food safety applications. Full article

Recent evidence suggests that microbiota-derived porphyrins contribute to skin aging, a phenomenon termed porphyr’aging. These pro-inflammatory molecules alter the expression of genes involved in senescence, trigger melanogenesis, and decrease collagen I synthesis in skin. The aim of this study was to evaluate the anti-aging properties of an upcycled Laminaria hyperborea extract (LHE) targeting bacterial porphyrins discovered after screening. The impact of LHE on porphyrin biosynthesis and on melanogenesis and wrinkles was evaluated using in vitro and ex vivo tests and by conducting a double-blinded vs. placebo clinical trial. LHE significantly reduced coproporphyrin III production in Gram-positive skin bacteria and significantly decreased porphyrin levels in vivo at the skin surface. This activity was supported by a specific composition of LHE, comprising laminaran and mannitol. It also significantly decreased melanin content in skin explants and pigmentation in the clinical study (−5.9%). This effect was particularly pronounced in dark spots (ITA +39.9%), and the number of precursor spots also decreased (−6.9%). In addition, LHE significantly stimulated type I α-1 pro-collagen production in fibroblasts and increased collagen I and elastin expression in skin explants. These results were consistent with the clinical study, showing significant reductions in wrinkle number (−9.8%) and area (−5.8%). These findings suggest that targeting microbiota-derived porphyrins and their consequences may represent a promising approach to reduce the visible signs of aging. Full article

Bacterial extracellular vesicles (BEVs) are nanoscale spherical lipid bilayer structures secreted by bacteria, including outer membrane vesicles (OMVs) released by Gram-negative bacteria and membrane vesicles (MVs) produced by Gram-positive bacteria. Although the biogenesis of BEVs requires substantial energy expenditure, these vesicles provide bacteria with strategic advantages in the evolutionary interplay between pathogens and hosts. BEVs contribute to bacterial adaptation to environmental stress by remodeling membrane components, eliminating toxic substances, promoting biofilm formation, and mediating the interbacterial transfer of antibiotic resistance determinants. They can also function as decoys to protect bacteria from bacteriophage or antibiotic attack, deliver virulence factors, modulate host immune responses to facilitate bacterial colonization, and mediate interspecies competition. This review summarizes the central roles of BEVs as bacterial mediators of environmental responses, with particular emphasis on their involvement in immune regulation, environmental adaptation, and interspecies competition, thereby providing new insights into pathogen evolutionary strategies. Full article

Marine-derived microorganisms are a rich source of structurally diverse natural products with significant pharmaceutical potential. In this study, three new cyclic lipopeptides, amylimycins A–C (1–3), were isolated from a marine-derived Bacillus amyloliquefaciens strain. The chemical structures of these compounds were elucidated through comprehensive spectroscopic analyses and chiral derivatization using 1-fluoro-2,4-dinitrophenyl-5-alanine amide (FDAA). Amylimycins A–C (1–3) were identified as bacillomycin D analogs belonging to the iturin family, characterized by a cyclic heptapeptide core linked to a β-amino fatty acid moiety. Notably, these compounds featured uncommon branched β-amino fatty acid chains with varied chain lengths, representing a distinctive structural characteristic among bacillomycin D analogs. Amylimycins A–C (1–3) showed moderate antibacterial activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus epidermidis, while displaying weak to no activity against the Gram-negative strains Escherichia coli and Pseudomonas fluorescens. Full article

This study presents a transformative “one-pot” biorefinery approach for the simultaneous production of hyaluronic acid (HA) and polyhydroxybutyrate (PHB) using an engineered, non-pathogenic Halomonas bluephagenesis TD01 chassis. By leveraging the principles of Next-Generation Industrial Biotechnology (NGIB), a one-step fermentation process was developed in nutrient-rich 40-LBG-Y medium, achieving a balanced metabolic flux that yielded 1.99 g/L and high-molecular-weight (HMw) HA (9.6 × 10⁶ Da) as the highest HA-Mw reported by heterogeneous bacteria, alongside intracellular PHB (0.68 to 1.6 g/L). A bioactive HA-PHB nanoparticle scaffold was fabricated, exhibiting a highly porous, interconnected 3D sponge-like architecture with a significant particle size shift from 12 nm to 450 nm, confirming successful polymer complexation. Antimicrobial evaluations revealed that the scaffold exhibited preliminary antimicrobial potential against representative Gram-positive and Gram-negative strains against Staphylococcus aureus, Klebsiella variicola, and Candida albicans. Notably, while Pseudomonas aeruginosa metabolically exploited purified HA, the integrated scaffold reversed this effect, providing preliminary antimicrobial potential by sterically hindering bacterial hyaluronidases. Furthermore, Halomonas-derived HA consistently outperformed Moringa oil and complex emulsions in preliminary tests against a wide range of pathogenic microbes. These results demonstrate that this dual-product platform provides a sustainable, cost-effective source of high-performance functional materials for advanced antimicrobial coatings and clinical wound management. Full article

Several strategies can be employed for the identification of novel microbial lipases. Despite the increasing importance of metagenomics in bioprospecting, significant limitations in the expression of recombinant proteins, and lipases in particular, remain. Culture-based bioprospecting approaches are, therefore, still valuable. In this work, a collection of bacterial isolates, mainly of marine origin, was screened for lipase activity through a culture-based approach. Screening for lipolytic bacteria was performed in solid media containing olive oil emulsions and rhodamine B. Positive isolates were subsequently grown in liquid media, to confirm lipase production. Significant hydrolytic activity towards the triglyceride substrates tributyrin and triolein could be observed with the biomass produced, although no lipase activity could be detected in the culture supernatants. Six isolates presenting high activity were characterized as whole-cell biocatalysts, and all were found to be active at temperatures ranging between 25 and 65 °C, and at pH values between 6 and 10.5. Genomic analyses of two of these Gram-negative lipase-producing isolates revealed the presence of several hypothetical genes encoding for lipolytic enzymes, including outer cell-bound enzymes, predicted through the application of machine-learning tools. These natural isolates, containing cell-associated lipases, may therefore be of special interest for application as whole-cell biocatalysts. Full article

Background/Objectives: Resistant pathogenic bacteria and fungi are a growing problem worldwide; therefore, the discovery of new active ingredients is an important challenge for which the functionalization of natural terpenes with biologically active heterocycles can provide a basis. To reach this goal, a series of 1,4-disubstituted-1,2,3-triazole conjugates was designed and synthesized starting from commercially available α-santonin. Methods: The key azido derivative intermediate was prepared according to literature procedures via Michael addition between dehydrosantonin and the TMSN₃/AcOH/Et₃N system at its highly reactive α-methylene-γ-lactone motif. Subsequently, the obtained azide was applied to regioselective Huisgen 1,3-dipolar cycloaddition reaction with a wide range of terminal alkynes bearing N-, S- and O-heterocycles. These include pyridine, pyrimidine, purine, quinoline, indol, or coumarin to afford the sesquiterpene–heterocycle chimaeras. All triazole conjugates were screened for in vitro antiproliferative activity by MTT assay against HeLa, MDA-MB231, SiHa, MCF-7 and A2780 human cancer cell lines compared with fibroblast cells (NIH/3T3) to check their cytotoxicity and antimicrobial effects on two Gram-positive (B. subtilis, S. aureus) pathogenic bacteria, two Gram-negative (E. coli and P. aeruginosa) pathogenic bacteria, and two yeasts (C. krusei and C. albicans). Results: The results indicated that most of the examined compounds expressed weak activity against human cell lines, while some of them showed moderate activity against S. aureus (up to 99% inhibition at 100 µg/mL conc.), C. krusei (up to 51% inhibition at 10 µg/mL conc.) and C. albicans (up to 52% inhibition at 10 µg/mL conc.). Conclusions: Further structural modification of the best, selective antibacterial and antifungal compounds may open the possibility to the development of effective natural sesquiterpene-based selective antimicrobial agents. Full article

Background/Objectives: Oral and maxillofacial infections present polybacterial profiles, including both aerobic and anaerobic bacteria. Increasing antibiotic resistance poses a significant challenge to pharmacological treatment of these infections. The aim of this study was to present a bacterial profile and assess antibiotic resistance found in these infections. Methods: This retrospective analysis is based on medical records of 224 patients affected with maxillofacial infections. Microbiological cultures and antibiotic susceptibility testing were performed for all patients. Results: In 78.57% of the patients, a positive microbiological culture was obtained. A total of 72.72% of culture-positive patients showed multi-bacterial cultures (128/176). Predominant bacteria included Streptococcus, detected in 156 cases (39%), followed by Staphylococcus, found in 64 cases (16%), and Prevotella, detected in 56 of 400 total bacterial isolates (14%). The most often isolated aerobic strains were Streptococcus mitis/oralis detected in 64 (16%) cases and Staphylococcus epidermidis detected in 48 cases (12%), while the most common anaerobic strains were Prevotella buccae detected in 14 cases (3.5%). Streptococcus and Staphylococcus exhibited the greatest resistance to clindamycin, accounting for 51.74% and 47.63%, respectively. Aerobic Gram-positive cocci were more resistant to penicillin and amoxicillin than to cephalosporins. Among obligate anaerobes, the lowest antibiotic resistance seen was to metronidazole. The obligate anaerobes except Prevotella were sensitive to clindamycin. Conclusions: A high rate of clindamycin resistance among aerobic and facultatively anaerobic Gram-positive cocci indicates the need to reassess the use of clindamycin in empirical therapy. The bacterial composition of infections suggests the need to use combined antibiotic therapy. First- and second-generation cephalosporins may be an effective alternative to penicillin and its derivatives. Full article

To improve clinical decision-making about Carbapenem-resistant Gram-negative bacteria (CR-GNB) infections and halt the spread of resistant microbes, quicker and less expensive diagnostic techniques are required. Thus, the purpose of this study was to thoroughly evaluate the diagnostic efficiency (sensitivity, specificity, and concordance) of direct-from-specimen multiplex lateral flow immunoassay (LFIA) across diverse raw clinical specimens and pathogen types from critically sick patients. A total of 300 non-duplicate samples were tested to detect CR-GNB. Five major Carbapenemase genes were detected directly from the specimen using carbapenem-resistant K.N.I.V.O. detection K-Set and from culture using culture-enhanced multiplex PCR. Turnaround time (TAT) of each method was calculated. The direct LFIA revealed 100% specificity for NDM, KPC, and IMP enzymes in all tested clinical matrices (blood, urine, and respiratory samples). The study demonstrated 100% sensitivity and specificity with perfect categorical agreement (κ = 1.000) for the blaKPC in the Klebsiella pneumoniae and for blaOXA-48 and blaIMP in the Acinetobacter baumannii; however, sensitivity of blaVIM was significantly diminished across all isolates and samples. TAT decreased significantly (p < 0.001) from 30 to 70 h to about 50 min. The tested direct LFIA facilitates the prompt enhancement of lifesaving tailored antibiotic treatment for severe illnesses. Full article