Search Results (9,695)

To address the limitation of traditional broad-spectrum antimicrobial agents in compromising skin microbiota homeostasis, this study developed Lactobacillus plantarum fermented milk (FM) as an innovative strategy for selectively regulating microbial communities to restore skin microbiota balance. FM was produced through protease hydrolysis in combination with L. plantarum fermentation. Selective antibacterial properties were evaluated via monoculture experiments (Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis) and pathogen–commensal co-culture systems. It was found that FM can selectively inhibit pathogens (E. coli and S. aureus) and promote the growth of commensal bacteria (S. epidermidis) in monoculture, and can reduce the growth and competitiveness of E. coli and S. aureus while relatively increasing the colony count of S. epidermidis in the co-culture system. Metabolomic profiling was further performed to identify metabolic alterations induced by FM. It was found that FM can activate the pyruvate metabolic node, significantly enhancing the metabolic fluxes of lactic acid, citric acid, and short-chain fatty acids, which triggered the acid stress response of pathogenic bacteria while consuming a considerable amount of energy, attenuating their reproductive capacity without impacting the growth of commensal bacteria. Overall, FM showed selective antimicrobial activity against pathogens (E. coli, and S. aureus) and preservation of commensal S. epidermidis, offering a foundational reference for the development of postbiotics aimed at maintaining cutaneous microbial homeostasis. Full article

Background/Objectives: Ocular drug delivery faces significant challenges due to anatomical and physiological barriers that limit drug bioavailability, particularly with conventional eye drops. Levofloxacin (LEVO), a broad-spectrum antibiotic, is widely used in the treatment of bacterial conjunctivitis, but its therapeutic efficacy is hindered by rapid precorneal clearance and short residence time. Methods: This study introduces a biorelevant 2 mL dissolution model to simulate ocular conditions better and evaluate the release kinetics of LEVO-loaded nanofibrous ophthalmic inserts. Compared to the conventional 40 mL setup, the 2 mL system demonstrated a slower and more sustained drug release profile, with kinetic modeling confirming a more controlled release behavior. Difference and similarity factor analysis further validated the distinct release profiles, highlighting the impact of dissolution volume on release dynamics. Results: Preliminary pharmacokinetic modeling suggested that the nanofiber inserts, particularly when applied twice daily, maintained levofloxacin concentrations above minimum inhibitory and bactericidal levels for extended durations across three bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus), potentially outperforming traditional eye drops. Conclusions: These findings suggest that small-volume dissolution testing may provide a more realistic method for evaluating ophthalmic insert formulations, though in vivo validation is needed. Moreover, the nanofibrous inserts show potential as a sustained-release alternative that warrants further investigation to improve patient compliance and therapeutic outcomes in ocular disease management. Full article

Background: Skin infections caused by Staphylococcus aureus represent a major public health concern, and plant extracts, such as those from Cochlospermum regium, have emerged as promising therapeutic alternatives. Methods: This study developed carbopol-based gel formulations containing ethanolic leaf extracts of C. regium (CRG 0.5% and 1%) and evaluated their physicochemical stability, antibacterial activity against S. aureus and a methicillin-resistant wound isolate, antioxidant potential, and biocompatibility. Results: Both CRG 0.5% and 1% were physically stable and maintained antibacterial activity for up to 90 days at 8 °C, while at 25 °C only CRG 1% retained activity throughout the evaluation period. In ex vivo pig skin assays, CRG 1% reduced methicillin-resistant S. aureus contamination by 99%, outperforming the conventional topical antibacterial agent (neomycin + bacitracin), which achieved 66% inhibition. The extract also exhibited high antioxidant activity without mutagenic or hemolytic effects. Although phenolic and flavonoid contents decreased over time, CRG 1% preserved adequate levels for therapeutic application. Conclusions: These findings indicate that CRG 1% has potential as a stable, safe, and effective alternative for the treatment of topical infections, particularly those caused by methicillin-resistant S. aureus. Full article

This article focuses on the utilization of the supramolecular self-assembly of renewable materials derivatives to obtain functional compounds. Novel bio-based amphiphile molecules (CALAH and PALAH) were synthesized through a tailored process, involving Williamson ether synthesis and amidation reactions, employing renewable amino acid and cashew nut shell liquid (CNSL) derivatives as essential reactants. Their molecular structures were confirmed by nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and Fourier-transform infrared spectroscopy (FT-IR). Notably, these compounds self-assemble into nanofibers that organize into a fibrous network, unexpectedly exhibiting two distinct morphologies: curved and rigid nanostructures. These structures were characterized by scanning electron microscopy (SEM), and their formation mechanisms were elucidated through temperature-dependent NMR studies and density functional theory (DFT) calculations. The sodium salts of the compounds (PALA and CALA) exhibited fundamental surfactant properties, exhibiting a hydrophilic lipophilic balance (HLB) value of 13.7 and critical micelle concentration (CMC) values of 1.05 × 10⁻⁵ M and 4.10 × 10⁻⁶ M. They also demonstrated low cytotoxicity, suggesting potential suitability in consumer applications. Furthermore, the compounds exhibited multi-functional performance as effective inhibitors of Staphylococcus aureus and efficient adsorbents for gaseous pollutants. Full article

The role of petting zoo animals in the dissemination of disease has been widely studied, yet understanding the potential reservoir of antimicrobial resistance (AMR) in these centres has not been explored in the United Kingdom (UK). To understand the carriage of AMR pathogens within petting zoos, this study aimed to identify AMR in E. coli and Staphylococcus intermedius group (SIG) isolated from faeces and skin, respectively, including selective cultures for ESBL-E. coli and methicillin-resistant staphylococci. Faecal samples and skin swabs were collected from 166 petted mammals across eight UK centres to recover E. coli and coagulase-positive staphylococci (CoPS), respectively, through enrichment culture methods, plating onto non-selective (tryptone bile-x agar, mannitol salt agar) and selective media (ESBL ChromID, mannitol salt agar with 6 mg/L oxacillin). Antimicrobial susceptibility was assessed using Kirby-Bauer disc diffusion, covering eight classes of antimicrobials. Antimicrobial usage records from the past 12-months were obtained from 7/8 centres. Overall, 145/166 faecal samples yielded 223 E. coli isolates, with an overall AMR prevalence of 42.6%. Thirteen E. coli isolates (from 8.5% of animals) were classified as multidrug-resistant. ESBL-producing E. coli were detected in 5/166 faecal samples. From 166 skin swabs, 84 yielded CoPS isolates, with S. aureus (n = 70), SIG (n = 13) and S. hyicus (n = 1) identified. Overall, 25.3% of SIG isolates exhibited resistance to at least one antimicrobial. Antimicrobial usage correlated positively with AMR prevalence for E. coli (p < 0.001), though was not associated with multidrug-resistance. This study demonstrates for the first time the presence of AMR within bacteria isolated from UK petting zoo animals, highlighting this reservoir of AMR bacteria. Full article

Background: In animals, staphylococci constitute a significant part of the normal skin microbiota and mucous membranes. There is limited information available on staphylococci isolated from healthy horses. These skin-associated bacteria can be easily transferred between animals and horse riders via direct contact. Patients undergoing hippotherapy (i.e., medical or therapeutic sessions with horses) are especially at risk of being colonized by horse skin-associated bacteria. However, it remains unclear whether equine skin is colonized by antimicrobial-resistant (AMR) opportunistic pathogens, which may be of concern to human health. Methods: We cultivate staphylococci from samples collected from healthy, non-vet-visiting horses who live on private farms in a rural area. In total, 61 strains were isolated and identified at the species level using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Results: The diversity of Staphylococcus species in the equine skin microbiota was relatively high and, with the exception of S. aureus, all the other recovered strains were coagulase-negative staphylococci (CoNS). In total, eleven different staphylococcal species were identified: S. xylosus, S. sciuri, S. vitulinus, S. equorum, S. succinus, S. nepalensis, S. lentus, S. fleurettii, S. aureus, S. chromogenes, and S. simulans. Conclusions: These results indicate that healthy equine skin is colonized by opportunistic pathogens that can be causative agents of infections that are also severe in humans. The resistance among the isolated strains was observed in eight antimicrobials of the total tested and 36% (22/61) of the isolates were resistant to at least one antimicrobial. However, their resistance to critically important antibiotics used in human medicine was low. Seven isolates (11.5%; 7/61) were classified as multidrug-resistant (MDR). S. aureus (1/61) showed MDR and was methicillin-resistant. The S. aureus isolate contained genes conferring resistance to antibiotics, i.e., β-lactams (blaZ, mecA), aminoglycosides (aac(6′)/aph(2″)), and macrolide–lincosamide–streptogramin B (erm(B), erm(C), and lun(A/B)). Also CoNS harbored genes conferring resistance to β-lactams (blaZ), aminoglycosides (aac(6′)/aph(2″), ant(4′)-Ia), MLSB (erm(B), erm(C), lun(A/B)), and tetracycline (tetK, tetL). Full article

Acute rhinosinusitis in children is typically caused by viral or bacterial infections. However, methicillin-resistant Staphylococcus aureus (MRSA) is increasingly linked to recurrence and severe complications, including orbital involvement. We present a case of a 6-year-old boy with periorbital swelling, proptosis, and fever following upper respiratory symptoms. Imaging revealed pansinusitis with a subperiosteal orbital abscess. He was treated empirically with intravenous ceftriaxone and metronidazole, followed by endoscopic sinus surgery. Intraoperative cultures confirmed MRSA, leading to a switch to vancomycin. The patient recovered fully without complications. This case illustrates the clinical challenges posed by MRSA sinusitis and emphasises its public health implications. Integrating antimicrobial stewardship, promoting community hygiene, ensuring early diagnostics and healthcare access, and enhancing epidemiological surveillance can play a pivotal role in reducing the burden of MRSA-related complications in children. Full article

In the pursuit of addressing the persistent challenge of bacterial adhesion and biofilm formation in dental care, this study investigates the efficacy of electric current as an alternative strategy, specifically focusing on its application in dental contexts. Polyether ether ketone (PEEK), known for its excellent biocompatibility and resistance to bacterial plaque, was enhanced with conductive properties by incorporating silver (Ag), a well-known antibacterial material. Through systematic in vitro experiments, the effectiveness of alternating current (AC) and direct current (DC) in reducing bacterial proliferation was evaluated. The tests were conducted using two bacterial strains: the Gram-positive Staphylococcus aureus and the Gram-negative Pseudomonas aeruginosa. Various configurations, current parameters, and two different electrode configurations were assessed to determine their impact on bacterial reduction. A notable finding from this study is that alternating current (AC) demonstrates superior efficacy compared to direct current (DC). The more significant decrease in CFUs/mL for P. aeruginosa with AC was recorded at the current levels of 5 mA and 500 nA. In opposition, S. aureus exhibited the greatest reduction at 5 mA and 1 mA. This study highlights the potential of using electric current within specific intensity ranges as an alternative strategy to effectively mitigate bacterial challenges in dental care. Full article

Bacteriocins from lactic acid bacteria have attracted considerable attention as natural alternatives to conventional antimicrobial agents. Weissellicin LM85, a bacteriocin purified from Weissella confusa LM85, has been less extensively studied in terms of its mechanism of action and potential applications. In this study, purified weissellicin LM85 exhibited potent inhibitory effects against Gram-positive bacteria, with minimum inhibitory and bactericidal concentrations determined against Micrococcus luteus MTCC106. Time-kill assays and fluorescence staining indicated a concentration-dependent reduction in cell viability, accompanied by membrane disruption. Further analyses revealed potassium ion efflux, dissipation of membrane potential (Δψ) and pH gradient (ΔpH), genomic DNA fragmentation, and pronounced morphological alterations in target cells. These findings are strongly suggestive of membrane-targeted bactericidal activity, likely involving pore-forming effects. In addition, weissellicin LM85 inhibited both growth and biofilm formation of Salmonella enterica subsp. enterica serovar Typhimurium ATCC13311 and Staphylococcus aureus subsp. aureus ATCC25923. Mechanistic analyses revealed the disruption of cell membrane integrity, leakage of potassium ions, cytoplasmic contents, and non-specific DNA degradation, indicating a multifaceted antibacterial mode of action. These findings highlight weissellicin LM85 as a promising natural antimicrobial with potential applications in food preservation and the control of foodborne pathogens and biofilm-associated infections. Further studies on cytotoxicity and in vivo efficacy are required to advance its practical application. Full article

Coconut oil is highly regarded for its nutritional and functional attributes, making it an attractive candidate for diverse food and health applications. This study evaluates the fatty acid profile, antioxidant and antimicrobial activities, oxidative stability, and sensory properties of selected coconut oils (Coco24, Health, Kospa, Smetol, and Vita) from the Slovak republic market. Acid values (0.09 ± 0.060–0.42 ± 0.060 mg KOH/g) and peroxide values (0.51 ± 0.058–1.20 ± 0.010 mmol O₂/kg) were within recommended safety limits. Oxidative stability varied significantly (p ˂ 0.05), with Smetol showing the highest induction time (124.5 ± 0.98 h) and Coco24 the lowest (25.8 ± 0.22 h). DPPH antioxidant activity was highest in health (469.2 ± 2.01 mg TEAC/kg) and Coco24 (369.3 ± 1.99 mg TEAC/kg) (TEAC—Trolox equivalent antioxidant capacity). Coco24, Health, and Kospa exhibited the most potent antimicrobial activity against Staphylococcus aureus (2.01 ± 0.001 mm, 1.37 ± 0.021 mm, 1.15 ± 0.010 mm, respectively), Candida glabrata (1.17 ± 0.015 mm, 1.17 ± 0.015 mm, 0.45 ± 0.025 mm, respectively), Candida tropicalis (2.12 ± 0.017 mm, 2.13 ± 0.017 mm, 1.52 ± 0.006 mm, respectively), and Bacillus subtilis (1.29 ± 0.055 mm, 1.35 ± 0.006 mm, 0.31 ± 0.020 mm, respectively). FAME analysis revealed that saturated fatty acids dominated, especially in Smetol (97.6 ± 0.067%), while Coco24 had the highest levels of unsaturated fatty acids. Vita and Kospa received the highest panel ratings for smell, taste, and overall acceptability, indicating superior sensory appeal, whereas Smetol scored the lowest. Correlation analysis showed strong positive relationships between MUFA and PUFA (r = 0.986) and taste and acceptability (r = 0.993), as well as between antioxidant activity and Candida albicans inhibition (r = 0.859). Oxidative stability was negatively correlated with PUFA (r = –0.924). PCA grouped oils high in MUFA/PUFA (Kospa, Vita) with superior sensory scores, while PC2 reflected microbial safety. These differences suggest that Coco24, Health, Vita, and Kospa offer enhanced functional and sensory benefits, whereas Smetol is better suited for applications that prioritize oxidative stability. Full article

We report for the first time a method for forming polyacrylate nanoparticles using N-acryloylciprofloxacin as a sole monomer for emulsion polymerization. The procedure involves a free radical-induced emulsion polymerization of N-acryloylciprofloxacin monomer to produce a stable aqueous emulsion comprising uniformly sized polyacrylate nanoparticles. Dynamic light scattering analysis of the emulsions showed a single population of nanoparticles having an average diameter of 970 nm and average surface charge of −63 mV, indicative of the high stability of the emulsion and significantly enhance lipophilicity of the polymeric matrix of the nanoparticle. Antibacterial testing of the emulsions against the Gram-positive microbe Staphylococcus aureus and the Gram-negative Escherichia coli found in vitro activities identical to those of the reference clinical agent, ciprofloxacin. Assays against human colorectal carcinoma cells and human embryonic kidney cells showed essentially no cytotoxicity. This is the first study on the synthesis of aqueous nanoparticle emulsions assembled solely from a single monomer derived from the antibiotic agent. Full article

Changes in membrane lipid composition constitute a key bacterial resistance mechanism. In Staphylococcus aureus, phosphatidylglycerol undergoes lysine modification to form lysyl-phosphatidylglycerol, a cationic lipid that reduces the net negative surface charge and thereby enhances resistance to cationic antimicrobial peptides. In this study, we examined the influence of lysyl-PG on the membrane activity of three antimicrobial peptides with distinct physicochemical characteristics: LL-37, F5W Magainin II, and NA-CATH:ATRA-1-ATRA-1. Model membranes composed of phosphatidylglycerol and cardiolipin were supplemented with increasing molar fractions of lysyl-phosphatidylglycerol, and peptide–membrane interactions were characterized using Fourier-transform infrared spectroscopy. Membrane fluidity was evaluated through shifts in the symmetric methylene stretching bands, while changes in interfacial polarity were assessed via the carbonyl and phosphate asymmetric stretching bands. LL-37 induced pronounced disruption of anionic bilayers, an effect progressively attenuated by lysyl-phosphatidylglycerol, particularly within the hydrophobic core. F5W Magainin perturbed both hydrophobic and interfacial regions across a broader range of lysyl-phosphatidylglycerol concentrations, whereas NA-CATH:ATRA-1-ATRA-1 primarily targeted interfacial domains, with minimal disruption of acyl chain order. Increasing lysyl-PG content modulated the extent of bilayer disorder and dehydration at the hydrophobic–hydrophilic interface, with each peptide exhibiting a distinct interaction profile. Collectively, these findings provide mechanistic insights into lysyl-PG-mediated modulation of peptide activity and highlight the role of lipid remodeling as a bacterial defense strategy. Full article

Background/Objectives: In this work, expanded electrospun poly(vinyl alcohol) (PVA) nanofiber mats incorporating tetracycline-loaded mesoporous silica nanoparticles (MSNs) were fabricated for antimicrobial wound dressing applications. Methods: MSNs with high surface area were synthesized and efficiently loaded with tetracycline, achieving sustained drug release. These nanoparticles were then embedded into both conventional (2D) and gas-expanded (3D) electrospun PVA mats. Results: The gas-foaming process significantly enhanced the mat’s thickness, promoting improved nanoparticle loading and diffusion properties. Physicochemical characterization confirmed the structural integrity, thermal stability, and successful drug incorporation within the hybrid scaffolds. Antimicrobial tests against Escherichia coli and Staphylococcus aureus demonstrated excellent bactericidal effects, with superior inhibition observed in 3D mats due to their higher drug loading capacity and faster drug release related to the expanded structure. Conclusions: These results highlight the potential of combining electrospinning, gas expansion, and nanocarriers to engineer advanced, drug-loaded fibrous scaffolds for wound healing. Full article

Background: Despite efforts to rely on arteriovenous fistulas/grafts for maintenance hemodialysis, a significant number of patients still depend on tunnel hemodialysis catheters for treatment. This poses a risk factor for central line-associated bloodstream infection (CLABSI) and, subsequently, vascular access compromise. Method: We conducted a retrospective study in five dialysis centers to determine the potential factors resulting in vascular access loss, CLABSI incidence, and microbe distribution patterns in Saudi Arabia at centers under the Ministry of National Guard Health Affairs. Adults who regularly received hemodialysis and had positive blood cultures between January 2019 and December 2023 were the subjects of the study. Results: Our study identified the presence of tunnel infection (p < 0.001), the presence of a Gram-negative pathogen (p = 0.036), and a high body mass index (BMI > 30) (p = 0.04) as potential risk factors leading to the loss of tunnel central venous catheters. In contrast, there was a lower probability of central venous catheter loss due to Gram-positive pathogens (p = 0.01). The CLABSI rate was 1.55 per 100 patients per month over a five-year period. Patients with CVC required more hospital treatment and had a significantly higher rate of vascular access loss (p < 0.001). Both central and peripheral blood cultures had nearly identical microbe spectra. Methicillin-sensitive Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus epidermidis had the highest prevalence rates among Gram-positive organisms. Among the Gram-negative bacteria, Enterobacter cloacae was the most common, followed by Klebsiella pneumonia and Pseudomonas aeruginosa. Conclusions: Our findings indicate the need for rigorous measures and interventions to prevent Gram-negative infections and decrease the reliance on central venous catheters, to decrease infections in hemodialysis patients, and decrease morbidity and cost. Strict hand hygiene, patient education, and surveillance programs are recommended to monitor these patients. Full article

Background/Objectives: Antimicrobial resistance is a critical global health challenge. Among resistant pathogens, the group of bacteria collectively referred to as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) is of particular concern due to their ability to evade multiple classes of antimicrobials. This study aimed to investigate the occurrence and resistance patterns of ESKAPE bacteria in wild birds from Northern and Central Italy sites, and to assess the presence of other bacteria of public health relevance. Methods: Cloacal swabs were collected from 141 wild birds. Samples were processed on selective and differential media, and bacterial identification was performed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Antimicrobial susceptibility was evaluated through Minimum Inhibitory Concentration assays and interpreted according to international guidelines. Results: Thirty-seven isolates belonging to the ESKAPE group were identified: E. faecium (n = 10), K. pneumoniae (n = 9), P. aeruginosa (n = 8), Enterobacter spp. (n = 7), S. aureus (n = 2), and A. baumannii (n = 1). Multidrug-resistant isolates were observed among K. pneumoniae and Enterobacter hormaechei. Escherichia coli, although not included in the ESKAPE group, was frequently detected and often co-isolated with clinically relevant bacteria, highlighting its potential role as a reservoir of resistance genes. Conclusions: Wild birds can harbor resistant bacteria of clinical importance, including multidrug-resistant ESKAPE species. Their presence in avian populations underscores the role of wildlife in the environmental dissemination of antimicrobial resistance, with implications for both animal and human health. Full article