Search Results (7,332)

A clinical strain of the opportunistic pathogen Serratia rubidaea, a known contaminant of healthcare environments and an emerging cause of invasive infections, is described. The studied isolate, recovered from a nurse’s hand skin swab during routine screening, exhibits a broad profile of antibiotic resistance combined with reduced susceptibility to several disinfectants. Phenotypic susceptibility testing using a tablet-based microdilution and disk diffusion method was employed to determine the minimum inhibitory concentrations (MICs) of antimicrobial agents from different classes, while broth microdilution assays with disinfectants revealed high-level tolerance to widely used agents, including 70% C₂H₅OH, 3% H₂O₂, 0.05% polyhexamethylene guanidine (PHMG) and others. Whole-genome sequencing identified multiple resistance-associated determinants, such as chromosome-encoded class C $\beta$-lactamase (ampC), several efflux systems (sdeXY, macAB, and emrAB) combined with multicopy tolC, and specific transferases (fos and arnT). Shotgun bottom-up HPLC-MS/MS proteomics confirmed baseline expression of these and other stress-tolerance-related proteins under non-inducing conditions. Taken together, these data underscore the importance of surveillance for Serratia spp. in healthcare facilities to detect strains that combine intrinsic or acquired multidrug resistance with robust survival traits such as disinfectant tolerance and biofilm formation. The present study provides a reference-level phenotypic, genomic, and proteomic characterization of a S. rubidaea clinical isolate, contributing to the understanding of the adaptive potential of this resilient opportunistic pathogen in clinical environments. Full article

Globally, the rise in MDR P. aeruginosa infections poses a serious threat to public health, as these strains frequently exhibit extensive resistance to conventional antibiotics, prompting interest in bacteriophages as alternative treatments. In this study, we isolated and characterized a lytic P. aeruginosa phage, vB_Pae_YuaWU01, from hospital sewage in southern Thailand. Morphological analysis revealed Siphovirus-like characteristics. The phage demonstrated efficient host adsorption, with approximately 85.9% of particles attached within 15 min, and exhibited a latent period of 50 min with a burst size of 17.2 PFU/cell. It showed strong lytic activity, consistently suppressing bacterial growth without no regrowth observed over 72 h. Notably, the phage significantly inhibited biofilm formation by up to 59.9% and reduced pre-established biofilms by 39.78% at the highest tested concentration (10⁹ PFU/mL). Genome analysis revealed a 61,824 bp double-stranded DNA genome with 64.48% GC content and 88 predicted genes. Bioinformatic analysis suggests that the genome is organized into structural, replication, and lysis modules. Importantly, no toxin, antimicrobial resistance, lysogeny, or tRNA genes were identified, suggesting a favorable safety profile. The phage was classified within the genus Yuavirus, showing 97.4% genomic similarity to Sphaerotilus phage SN1, which infects a different host strain. The findings highlight its potential as a genetically safe therapeutic agent; however, its limited host range indicates that it may be best positioned as a strategic component of phage cocktails or as a synergistic partner with antibiotics to maximize therapeutic efficacy. Full article

Antimicrobial peptides (AMPs) are natural bioactive peptides produced by all organisms—from plants to insects, microbes and animals—and constitute a first line of defense. As they exhibit a broad spectrum of activity (antibacterial, antiviral, antifungal, antiparasitic, anticancer), strong efforts are being made to integrate AMPs into clinical use. AMPs are also being investigated as anticancer agents to overcome the side effects and/or resistance associated with current chemotherapies. In this context, we identified the natural AMP chionodracine from a new biological source: an Antarctic fish. Starting from the fragmentation of a chionodracine mutant peptide, a rational modular design approach was applied to develop three very short peptides (Pep-A, Pep-B and Pep-C), which were further modified with an N-terminal myristic acid lipid tail. The anticancer activity of the three N-myristoylated short peptides (Myr-A, Myr-B and Myr-C) was explored against the human cervical cancer HeLa cell line. The rationale behind this study is based on the previously reported antifungal activity of these myr peptides and on their ability to interact selectively with biological membrane-mimicking synthetic phospholipids without being particularly hemolytic or cytotoxic towards normal cells. We first demonstrated that myr peptides had cytotoxic activity against HeLa cells (IC₅₀ from 32 to 47 μM) but spared healthy primary human fibroblasts, whereas the corresponding non-myr peptides failed to kill cancer cells. The peptide with no hemolytic activity and a low IC₅₀, labeled Myr-B, was selected for subsequent analyses. Lactate dehydrogenase (LDH) assay and scanning electron microscopy (SEM) analysis revealed membrane damage and predominantly necrotic cell death in HeLa cells exposed to IC₅₀ doses of the Myr-B peptide, compared with cells treated with Pep-B. To thoroughly investigate the molecular effects of Myr-B in HeLa cells, we employed high-resolution label-free shotgun quantitative proteomics coupled with bioinformatics. Our results showed that exposing HeLa cells to Myr-B led to the under-expression of proteins belonging to the “apoptosis- and splicing-associated protein complex”, potentially influencing the alternative splicing process and consequently leading to a possible susceptibility to programmed cell death. These findings indicate that modifying natural AMPs may be a promising strategy for developing selective anticancer drugs and pinpoint Myr-B as an interesting target for future studies. Full article

Diabetic chronic wounds (particularly diabetic foot ulcers) are difficult to heal due to factors such as high glucose levels, infection, and inflammatory imbalance. In severe cases, they can lead to tissue necrosis and amputation. Hydrogel materials, as moist wound dressings, possess high water content, biocompatibility, and tunability, making them an important platform for promoting diabetic wound healing. In recent years, novel smart hydrogels have been developed to integrate multiple functions. They respond to abnormal stimuli in the wound microenvironment—such as acidic pH, high glucose levels, or excessive reactive oxygen species—to trigger the release of drugs, delivering on-demand antimicrobial, antioxidant, and anti-inflammatory effects. Simultaneously, they modulate immune responses (promoting macrophage polarization toward the M2 type) and stimulate angiogenesis, creating a microenvironment conducive to tissue regeneration. Some hydrogels incorporate antimicrobial agents, anti-biofilm components, or photothermal/photodynamic agents to effectively eliminate drug-resistant pathogens and control infections. Others serve as carriers for delivering stem cells and their exosomes, enhancing cell survival rates and releasing growth factors to accelerate wound healing. This review systematically summarizes recent advances in hydrogel strategies for diabetic wound treatment, focusing on stimulus-responsive hydrogels, antimicrobial and immune modulation mechanisms, pro-angiogenic and oxygen-supplying therapies, smart dressings and monitoring technologies, integration of stem cells and exosomes, as well as hydrogel injection, self-healing, and adhesion properties. Based on this, we analyze challenges and prospects for clinical translation of these strategies. Collectively, functionalized hydrogels hold promise as multifunctional therapeutic platforms for diabetic non-healing wounds. They offer a multi-pronged approach to disrupt the vicious cycle of “infection–inflammation–tissue destruction” thereby achieving more efficient wound healing. Full article

Background/Objectives: Staphylococcus aureus persister cells significantly undermine antimicrobial therapy through their transient antibiotic tolerance, contributing to chronic and recurrent infections. Although monoglycerides have shown potential as membrane-active antimicrobial agents, their effect on persister cells remains insufficiently understood. Methods: In this study, we evaluated the anti-persister activities of monocaprin, monolaurin, and monomyristin against S. aureus persister cells. Mechanistic analyses were performed using membrane permeability assays and fluorescence microscopy. Results: All three monoglycerides reduced persister cell survival, with varying degrees depending on fatty acid chain length. Monolaurin exhibited the greatest anti-persister activity, whereas monocaprin and monomyristin exerted concentration-dependent bactericidal effects. Mechanistic analyses revealed that these compounds increased membrane permeability, thereby compromising cell viability in S. aureus persister cells. In contrast, Tween 80 attenuated both the bactericidal effect and the increase in membrane permeability, supporting the involvement of membrane disruption in their mode of action. Conclusions: The antibacterial activity of monocaprin, monolaurin, and monomyristin against S. aureus is closely associated with membrane damage. These membrane-active monoglycerides represent promising antimicrobial candidates for the eradication of S. aureus persister cells. Full article

As global demand grows for natural health-promoting food ingredients, the agri-food industry’s organic wastes are emerging as promising alternatives thanks to attributes such as biocompatibility, nutritional value and nutraceutical effect. During saffron (Crocus sativus L.) production, approximately 53 kg of petals are obtained as a by-product for every 1 kg of saffron spice. The use of saffron petals and petal extracts in bakery products improves products’ shelf life due to the petals’ high content of nutraceuticals and minerals acting as natural preservatives. Petal-enriched bakery products contain high levels of fiber, minerals and antioxidants. Addition of saffron petals into bread dough reduces gluten network strength, increases crumb hardness, enhances acidity, improves water retention, alters color profiles and increases the duration of the shelf life. The formulation for incorporating saffron petals or petal extracts into food products must address three primary criteria: the maximum concentration of bioactive compounds per 100 g of the finished matrix, the thermal stability of these compounds during the baking process, and their bioavailability (in the food matrix) within the human gastrointestinal tract. Nutraceuticals with pharmacological potential are also influenced by the compositional profile: the proximate composition, minerals, phenolic content, flavonols, and antioxidant capacity of saffron petals and bakery products containing saffron petals. Saffron petals exhibit diverse therapeutic potentials, acting as antidepressants, anxiolytics, anticonvulsants, and neuroprotective agents. They also offer metabolic, cardiovascular, hepatoprotective, and renoprotective benefits, along with anti-inflammatory, antimicrobial, and antitumor activities. This article proposes a roadmap for developing bakery products enriched with saffron petals or petal extracts, targeting both pharmacological applications and consumer goods focused on disease prevention and general wellness. This study investigates the biochemical composition of saffron petals and their integration into bakery products. It evaluates the influence of petal-derived additives on rheological properties, shelf stability, and organoleptic characteristics, alongside an assessment of their bioactivity and toxicological profiles. Furthermore, the analytical methodologies employed for ingredient and biological sample characterization are discussed, emphasizing their role in verifying the authenticity, safety, and nutritional functionality of both raw materials and finished formulations. Full article

The rise in antimicrobial resistance represents a significant challenge to global health. The reason partially lies in an inappropriate use of conventional antibiotics and the subsequent rapid spread of multidrug-resistant pathogen strains. This emergency requires an urgent search for conceptually new antimicrobial agents. A viable alternative to conventional antibiotics is antimicrobial peptides (AMPs), which are ribosomally synthesized molecules with considerable potential as next-generation anti-infectious therapeutics. Previously, we have reported on the β-hairpin peptide Ap9, an analog of abarenicin from the marine polychaeta Abarenicola pacifica, with potent activity against key Gram-negative pathogens. Here, it is shown that Ap9 acts in a manner resembling polymyxin B, namely via interaction with lipopolysaccharide (LPS), and retains its activity against polymyxin-resistant isolates without observed cross-resistance, and causes insignificant damage in cytoplasmic membrane at bactericidal concentrations. NMR spectroscopy reveals that LPS binding induces a conformational rearrangement of Ap9, its dimer formation, and local structural remodeling of the peptide region (residues 8–12) into 3₁₀-helix. Bacterial resistance to Ap9 was found to be relatively low with a reduced susceptibility associated with infrequent genetic alterations, such as the mutation in lptD or the deletion in mlaA. Furthermore, Ap9 demonstrates a favorable tolerability, a wider therapeutic window than that of polymyxin B, and a sufficiently long half-life through the systemic use, as well as in vivo efficacy in murine models of Gram-negative infections, including sepsis caused by the mcr-1-harboring Escherichia coli strain. The obtained results point to Ap9 as a promising candidate for further preclinical studies aimed at development of an alternative to polymyxins. Full article

Klebsiella pneumoniae, a member of the ESKAPEE group of priority pathogens, has become one of the most challenging bacterial pathogens in modern clinical practice, largely due to its multidrug resistance and the immune-evasive effect of its capsular polysaccharide (CPS). Phage-encoded depolymerases, which selectively degrade the capsular polysaccharide, have emerged as promising antimicrobial agents capable of restoring bacterial susceptibility to both immune clearance and phage infection. The fragment corresponding to the C-terminal region of a putative depolymerase of bacteriophage KlebP_144, namely DepKP144ΔC, was cloned, expressed in E. coli, and purified using immobilized metal affinity chromatography. DepKP144ΔC displays an enzymatic activity against capsular polysaccharides of 100% K1 capsular-type strains and 85% K2 capsular-type strains, including classical and hypervirulent isolates. It was demonstrated that this protein is capable of inhibiting K. pneumoniae biofilm formation, but it is unable to disrupt mature biofilms. In vivo experiments using a murine K. pneumoniae infection model further confirmed its therapeutic potential: treatment with DepKP144ΔC improved survival rate in mice infected with K2-type K. pneumoniae, indicating significant attenuation of bacterial virulence. Therefore, these results demonstrate the potential role of the C-terminal domain of the bacteriophage KP144 tail-fiber protein in phage entry and show that its carbohydrate-recognition motifs possess enzymatic activity against the Klebsiella capsular polysaccharides. Full article

Anti-inflammatory agents, antipyretics, and antibiotics are commonly used to manage fever and pain associated with infectious diseases in both adults and children. Despite their effectiveness, inappropriate and unnecessary prescriptions remain widespread, leading to adverse patient outcomes and, in the case of antibiotics, contributing to antimicrobial resistance. Addressing these issues requires effective stewardship programs focused on educating healthcare professionals and the public on evidence-based guidelines for optimal prescribing practices. This paper explores the five “A”s fundamental to infection management in pediatric and adult patients: appropriateness, abuse, antipyretics, anti-inflammatory agents, and antibiotics. Through a comprehensive literature review, expert perspectives, and clinical guidelines, the study evaluates the roles of anti-inflammatory agents (e.g., ibuprofen), antipyretics (e.g., paracetamol), and antibiotics in clinical practice, highlighting best practices for their use. Current guidelines emphasize that antipyretics should only be administered when fever is accompanied by significant discomfort or pain, as fever itself plays a role in the immune response. Based on the available literature, experts also suggest that paracetamol should be preferred as a first-line antipyretic due to its favorable safety profile, while ibuprofen should be used with caution, particularly during respiratory infections, varicella, and severe bacterial infections, due to its potential to exacerbate complications. According to experts, special consideration is also required for patients with renal or gastrointestinal comorbidities to prevent toxicity. Regarding antibiotics, prescriptions should be limited to clear evidence of bacterial infection to avoid unnecessary patient exposure and the development of antimicrobial resistance. Stewardship programs underscore the importance of selecting the right agent, optimizing dosing, and introducing shorter treatment regimens where supported by evidence, to improve therapeutic outcomes while minimizing resistance risks. Ultimately, this paper provides practical, evidence-based recommendations to support rational prescribing of antipyretics, anti-inflammatory drugs, and antibiotics, aiming to optimize patient outcomes, prevent unnecessary toxicity, and contribute to global efforts against antimicrobial resistance. Full article

Background: Sulfated chitosan (ChS) is a chemically modified polysaccharide derived from chitin that mimics heparan sulfate (HS) structures and has emerged as a promising antimicrobial biomaterial. Piscirickettsia salmonis, the etiological agent of Salmonid Rickettsial Septicemia (SRS), represents the main driver of antibiotic use in Chilean aquaculture. Objective: In this study, the in vitro antibacterial activity of ChS against P. salmonis was evaluated. Methods: Elemental characterization by SEM-EDS and FTIR analysis confirmed successful sulfation of the polymer, with a degree of sulfation ranging from 0.92 to 0.95. Additionally, X-ray diffraction (XRD) analysis revealed a reduction in polymer crystallinity, indicating a transition toward a more amorphous structure associated with increased molecular flexibility and functional group accessibility. Results: Antibacterial assays revealed a minimum inhibitory concentration (MIC) of 1500 µg/mL and a minimum bactericidal concentration (MBC ≥ 1500 µg/mL). LIVE/DEAD™ fluorescence imaging showed the formation of bacterial aggregates with increasing size, frequency, and red fluorescence compared to controls over the exposure to ChS, indicating progressive membrane damage. This was supported by a reduction (p < 0.05) in the Green/Red fluorescence ratio of 37–46% between 5 h and 96 h of exposure, corresponding to alteration of the cell membrane. Scanning electron microscopy revealed pronounced morphological alterations by ChS, including surface disruption and loss of cellular integrity. This was more severe compared to commercial chitosan (ChC). Also, ChS reduced (p < 0.05) biofilm formation (>50% at day 6 and 34.8% at day 8). Conclusions: These results demonstrated that ChS disrupts the cell membrane and reduces biofilm formation in P. salmonis, thereby affecting viability. This is the first report of the antibacterial effect of ChS, an HS analogue, against P. salmonis. Full article

Antimicrobial resistance in Escherichia coli (E. coli) is a major public health concern globally, driven by increased resistance to commonly used antimicrobial agents such as β-lactams and fluoroquinolones. The main goal of our research is to develop a machine learning framework to predict antimicrobial resistance in E. coli by integrating antimicrobial susceptibility testing data with genomic biomarker analysis. A dataset comprising 17,122 E. coli clinical isolates was obtained from the Bacterial and Viral Bioinformatics Resource Center (BV-BRC). After preprocessing, fivefold cross-validation was used to train and test five machine learning models: Random Forest, XGBoost, Support Vector Machine, Logistic Regression, and k-Nearest Neighbors. The highest-performing model was XGBoost, with 0.86 accuracy and 0.932 ROC-AUC, followed by Random Forest, with 0.82 accuracy and 0.89 ROC-AUC. Phylogenetic analysis revealed that resistant isolates clustered together relative to the reference genome of E. coli K-12 MG1655. Genomic biomarkers such as gyrA, parC, CTX-M-15, OXA-1, and various multidrug efflux pumps were identified by the Comprehensive Antibiotic Resistance Database (CARD) and ResFinder as significant resistance determinants in this study. In conclusion, this study demonstrates that combining antimicrobial susceptibility testing with machine learning and genomic biomarkers is a powerful framework for predicting antimicrobial resistance in E. coli. Full article

Chloramphenicol is a broad-spectrum antimicrobial agent whose use in food-producing animals is prohibited in many countries due to its association with severe adverse effects, including idiosyncratic aplastic anemia and genotoxicity. Despite these restrictions, chloramphenicol residues continue to be detected in food products, environmental compartments, and biological matrices, highlighting the need for reliable and sensitive analytical monitoring. This review provides a comprehensive overview of current analytical strategies for the detection of drugs in food and environmental samples, covering screening and confirmatory techniques, sample preparation approaches, and regulatory aspects. Rapid screening methods, such as enzyme-linked immunosorbent assays (ELISAs), lateral flow immunoassays (LFIAs), and biosensors based on antibodies, aptamers, and molecularly imprinted polymers, enable fast and cost-effective preliminary detection. Recent advances in nanomaterials and signal amplification strategies, including fluorescent reporters and surface-enhanced Raman scattering (SERS), have significantly improved sensitivity and assay performance. However, confirmatory methods based on liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) remain the reference standard due to their superior selectivity, sensitivity, and quantitative reliability. Attention is given to sample preparation workflows, including QuEChERS-based protocols and microextraction techniques, which enable efficient analysis of complex matrices. Finally, current regulatory frameworks and analytical challenges related to zero-tolerance policies are discussed, emphasizing the importance of robust and validated analytical methods for effective monitoring and food safety assurance. Full article

The rapid emergence of multi-drug resistant (MDR) bacteria has become a major health concern, driving the need to identify new antimicrobial resources. Recently, endophytes, inhabiting in internal tissues of medicinal plants, have drew important interest from the scientific community, as reservoirs of bioactive metabolites. Numerous studies highlight the symbiotic relationship between plants and their endophytes, in which these microorganisms produce antimicrobial compounds, helping the host plant’s defense against pathogens. Plantago major (commonly known as plantain) is widely recognized for its therapeutic properties, especially for its antimicrobial properties. In this study, endophytic fungi were isolated from Plantago major, morphologically characterized and identified using ITS sequencing. Their antibacterial activity was assessed using the agar diffusion assay. In total, 21 endophytic fungal isolates were obtained from different plant tissues, including leaves, stems, roots, and flowers. Antibacterial assays against methicillin-resistant Staphylococcus aureus (MRSA) were investigated on PDA, SDA, and CDA media. Amongst the isolates, nine strains (MD-H1, MD-L1, MD-L2, MD-L3, MD-L4, MD-L5, MD-R1, MD-T1, MD-T2, and MD-T10) showed medium to strong antibacterial effects, with inhibition zones exceeding 15 mm. The result suggests that endophytic fungi associated with Plantago is a valuable source of anti-MRSA compounds. Further work will focus on identifying the secondary metabolites responsible for this activity and elucidating their chemical structures, providing a basis for the development of new potent antibiotic agents. Full article

Neonatal infections remain a leading cause of morbidity and mortality worldwide, particularly among preterm and low-birth-weight infants and in low- and middle-income countries. This burden has intensified with the global increase in multidrug-resistant (MDR) bacteria, especially in neonatal intensive care units, where prolonged hospitalization, invasive interventions, and exposure to broad-spectrum antibiotics promote colonization, transmission, and invasive infection. In this narrative review, we explore the epidemiology and microbiological characteristics of MDR bacterial infections in newborns, alongside their associated risk factors, diagnostic challenges, treatment outcomes, and prevention strategies. Across different settings, Gram-negative pathogens, particularly Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii, account for a substantial proportion of severe neonatal infections, whereas methicillin-resistant Staphylococcus aureus remains important in selected units. The risk of MDR infection is driven by a complex interplay of factors, ranging from maternal and perinatal exposures to the inherent immunological vulnerability of newborns, hospital-based transmission, antibiotic selection pressure, and structural deficiencies in healthcare infrastructure. Diagnosis remains challenging because clinical presentations are nonspecific and culture-based methods are constrained by low blood volumes, prior antimicrobial exposure, and delayed turnaround times. Treatment is increasingly complicated due to resistance to standard empirical regimens, substantial regional variation in susceptibility profiles, and limited neonatal pharmacokinetic and safety data for reserve agents. Current evidence mainly supports surveillance-informed empirical therapy, susceptibility-guided treatment adjustment, antimicrobial stewardship, and strict infection prevention measures. Future progress will require neonatal-specific clinical trials, harmonized surveillance systems, stronger molecular epidemiology, and more equitable access to microbiological diagnostics and effective treatment. Full article

The present work aimed to obtain antibacterial wound dressings using bacterial cellulose (BC) as a support, to improve wound treatment and reduce the incidence of infections. To enhance the antibacterial activity of the synthesized dressings, the introduction of ZnO nanoparticles into the BC network by precipitation was pursued. The method chosen to develop ZnO NPs was green synthesis, an ecological and sustainable method for obtaining nanomaterials using plant extracts as reducing agents or stabilizers. Thus, the chosen plants were Ginger rhizomes, Bay leaves, and Rose hips, in both fresh and dry form, due to the natural benefits they possess, and the Soxhlet method was used to obtain the plant extracts desired to be used in the synthesis. The composite dressings were developed in two distinct sample series, differentiated by the immersion time of BC in the precursor Zn²⁺ solution. The samples in the first series were obtained by precipitation in a mixture of Zn²⁺ solution and natural extract, whereas the samples in the second series were obtained by successive immersion in Zn²⁺ solution and then in natural extract, which demonstrated a considerable difference. The best antimicrobial activity tested against Gram-negative bacterium Escherichia coli was recorded for the composite material obtained in the presence of fresh rose hip extract, an aspect most likely related to the morphological and crystalline features of the ZnO phase, but also to the phytochemical profile of the extract used. Such eco-friendly materials represent valuable candidates for wound dressing applications due to their ability to support wound healing, relief burns, and skin irritation, provide antimicrobial protection, promote skin regeneration and reduce scarring, protect sensitive skin, and act as a barrier against external contaminants. Full article