Skin Infections Research Articles

Post-war status of water supply, sanitation, hygiene and related reported diseases in Tigray, Ethiopia: A community-based cross-sectional study

Water, sanitation and hygiene (WASH) associated diseases remain a global public health issue and linked with Sustainable Development Goal 6. In November 2020, a war broke out in Tigray, Ethiopia, resulting in a negative health consequence. The post war status of WASH and its associated diseases are not documented. The aim of this study was to assess the status of drinking water, sanitation and hygiene practices and the prevalence of WASH-associated diseases in Tigray, Ethiopia following the war. A community-based cross-sectional study was conducted in 24 randomly selected accessible districts of Tigray, Ethiopia. A standardized questionnaire was used to collect data from households in the study. Data was collected from 2338 households. Descriptive statistics and binary logistic regression were used to analyze the data. The average age of respondents was 28.7 years (SD = 6.2). The majority of respondents 2030 (86.8%) were married and 1698 (72.6%) were rural residents. Nearly one third of the respondents were uneducated and around 40% have either radio or TV as means of communication. More than half (55.2%) of the respondents had a family size of over 5.A quarter (25%, 95% CI: 23.3, 26.8) of study participants had access to a basic water supply. Less than a tenth (7.7%, 95% CI: 6.6, 8.8) of households had access to basic sanitation. Basic hand washing was available in 2% of households. Malaria, diarrhoea, skin infection and eye infection were the common reported disease in the community. Marital status, family size, place of residence and liquid waste management were the most important predictors of reported diseases.Access to basic water, sanitation and hygiene services was low, and the prevalence of malaria, diarrhoea and skin infections was higher. There were differences in WASH services and reported diseases according to zone and place of residence (urban-rural). Post war, improved access to basic water, sanitation and hygiene services is recommended to prevent WASH-associated diseases in Tigray, Ethiopia. Furthermore, the prevention oriented policy of the country needs better implementation to reduce preventable diseases and ensure better health status in the community.

On-Demand Removable Chitosan Based Self-Healing and Antibacterial Hydrogel for Delivery of Tetracycline and Curcumin As Potential Wound Dressing Material.

Wound care is a flourishing branch of healthcare wherein a great amount of research is devoted to develop competent wound dressings. Safe, cost-effective, and biocompatible dressings aid in wound healing without inflicting external trauma and subsequent scar formation. Toward this, we have attempted to develop robust wound dressing material with self-healing and antibacterial properties. We have cross-linked chitosan with 4-formyl phenylboronic acid (4-FPBA) and in situ generated dehydroascorbic acid (DHA) utilizing the dynamic imine and boronate ester linkages. Displaying a channeled microstructure in the SEM micrographs, the hydrogel exhibits a massive water uptake capacity of ∼900% at acidic pH. The hydrogel could completely self-heal within 3 min, and the results are further supported by rheological analysis. By virtue of positive surface charge, it shows a promising tissue adhesive property. Moreover, it affords clean and compliant removal from the wound surface via dissolution induced by dopamine to potentially reduce secondary scarring from peeling of wound dressings. The dressing could significantly act against skin infections caused by S. aureus bacteria with enhanced antimicrobial efficiency via loading of antibiotic drug, tetracycline hydrochloride. A sustained release of tetracycline and Curcumin was observed, which demonstrated the release ability for hydrophilic and hydrophobic bioactive agents. In-vitro studies revealed 93% cell viability with a hemolytic ratio as low as 2.5%, thereby presenting a good self-healing and biocompatible material for wound healing.

Gram stain of skin tissue sections: The difficulty in establishing diagnostic standards for skin and soft tissue infections.

Gram stain of skin tissue sections: The difficulty in establishing diagnostic standards for skin and soft tissue infections.

Retrospective clinical and microbiologic analysis of metagenomic next-generation sequencing in the microbiological diagnosis of cutaneous infectious granulomas

BackgroundCutaneous infectious granulomas (CIG) are localized and chronic skin infection caused by a variety of pathogens such as protozoans, bacteria, worms, viruses and fungi. The diagnosis of CIG is difficult because microbiological examination shows low sensitivity and the histomorphological findings of CIG caused by different pathogens are commonly difficult to be distinguished.ObjectiveThe objective of this study is to explore the application of mNGS in tissue sample testing for CIG cases, and to compare mNGS with traditional microbiological methods by evaluating sensitivity and specificity.MethodsWe conducted a retrospective study at the Department of Dermatology of Sun Yat-sen Memorial Hospital, Sun Yat-sen University from January 1st, 2020, to May 31st, 2024. Specimens from CIG patients with a clinical presentation of cutaneous infection that was supported by histological examination were retrospectively enrolled. Specimens were delivered to be tested for microbiological examinations and mNGS.ResultsOur data show that mNGS detected Non-tuberculosis mycobacteria, Mycobacterium tuberculosis, fungi and bacteria in CIG. Compared to culture, mNGS showed a higher positive rate (80.77% vs. 57.7%) with high sensitivity rate (100%) and negative predictive value (100%). In addition, mNGS can detect more pathogens in one sample and can be used to detect variable samples including the samples of paraffin-embedded tissue with shorter detective time. Of the 21 patients who showed clinical improvement within a 30-day follow-up, eighteen had their treatments adjusted, including fifteen who continued treatment based on the results of mNGS.ConclusionsmNGS could provide a potentially rapid and effective alternative detection method for diagnosis of cutaneous infectious granulomas and mNGS results may affect the clinical prognosis resulting from enabling the patients to initiate timely treatment.

Specific Antidermatophytic Activity of Trifluoromethylthiolated Cinnamate Derivatives: A New Approach to the Therapy of Superficial Fungal Infections of the Skin

AbstractDermatomycoses are the most widespread fungal skin infections worldwide and directly affect patients’ quality of life. They are challenging to manage because of the need for prolonged treatment and the development of resistance to antifungal agents. This article studies the antifungal activity of trifluoromethylthiolated cinnamate derivatives on Candida species and dermatophytes as well as possible mechanisms of action, irritability, and cytotoxicity tests. These molecules show activity against dermatophyte fungi with minimum inhibitory concentrations (MIC) as low as 0.39 μg mL−1. In particular, chloroaromatic derivatives demonstrated the best inhibition profile (1.56–6.25 μg mL−1). Importantly, our series of molecules were not active against Candida spp., being selective for dermatophytes. A study of the mechanism of action suggests that our SCF3 cinnamates do not bind directly to ergosterol or the cell wall. The physicochemical parameters and the absence of irritability resulting from the HET‐CAM test demonstrate that compound 8 can be considered a future candidate for the therapy of dermatophytosis.

A triple-mode strategy combining low-temperature photothermal, photodynamic, and chemodynamic therapies for treating infectious skin wounds.

The skin is the first natural barrier of the human body. Bacterial infections severely hinder the healing process of skin wounds and pose a great threat to human health. Therefore, it is particularly urgent to develop new antimicrobial strategies for bacterial pathogen clearance and wound healing. In this study, a metal-organic framework (MOF), Fe-MIL88B-NH2, was incorporated with the photosensitizer indocyanine green (ICG) to construct composite nanoparticles (MOF@ICG NPs) with multiple antibacterial activities. Under mild near-infrared (NIR) irradiation, the photosensitizer ICG in the MOF@ICG NPs undergoes photothermal conversion (∼45 °C) and photodynamic reactions to generate heat and singlet oxygen (1O2). In addition, the Fenton reaction of the NPs with hydrogen peroxide (H2O2) in the bacterial infection microenvironment resulted in the generation of hydroxyl radicals (˙OH), thus achieving the three-mode combination of low-temperature photothermal therapy (PTT)/photodynamic therapy (PDT)/chemodynamic therapy (CDT). The in vitro experimental results showed that MOF@ICG MPs had excellent antibacterial properties and good cytocompatibility, with some ability to promote the migration of L-929 fibroblasts. Furthermore, under NIR irradiation, MOF@ICG NPs could significantly kill bacteria and promote skin wound healing according to the results of animal experiments. The wound healing rate reached 87.1% after 7 days of treatment. The research results break through the limitations of single-mode antibacterial technology and provide certain theoretical guidance and technical support for the research and development of new antibacterial materials.

Pre- and Post-admission Care for Children Hospitalized With Skin and Soft Tissue Infections.

Although skin and soft tissue infections (SSTIs) are among the most common indications for pediatric hospitalization, little is known about outpatient care received for SSTI before and after hospitalization. We assessed peri-hospitalization care for SSTI, including antibiotic exposures and their impact on hospital length of stay (LOS). This is a retrospective cohort study of 1229 SSTI hospitalizations in 2019 from children aged 1-to-18 years enrolled in Medicaid from 10 US states included in the Merative Marketscan Medicaid database. We characterized health service utilization (outpatient visits, laboratory and diagnostic tests, antibiotic exposures) 14 days before and 30 days after hospitalization and evaluated the effects of pre-hospitalization care on hospital LOS with linear regression. Only 43.1% of children hospitalized with SSTI had a preceding outpatient visit with a SSTI diagnosis, 69.8% of which also filled prescription for an antibiotic. Median LOS for SSTI admission was 2 days (interquartile range 1-3). Pre-hospitalization visits with a diagnosis of SSTI were associated with a 0.7 day reduction (95% confidence interval: 0.6-0.81) in LOS (P < .001), but pre-hospital antibiotic exposure alone had no effect on LOS. Most children (81.7%) filled antibiotic prescriptions after hospital discharge and 74.5% had post-discharge ambulatory visits. Although most children did not receive pre-admission care for SSTI, those that did had a shorter hospitalization. Further investigation is necessary on how to optimize access and use of outpatient care for SSTI.

BRAF Inhibition and UVB Light Synergistically Promote Mus musculus Papillomavirus 1-Induced Skin Tumorigenesis.

The development of keratinocytic skin tumors, presumably attributable to paradoxical activation of the MAPK pathway, represents a relevant side effect of targeted therapies with BRAF inhibitors (BRAFis). The role of cutaneous papillomavirus infection in BRAFi-associated skin carcinogenesis, however, is still inconclusive. Employing the Mus musculus papillomavirus 1 (MmuPV1) skin infection model, the impact of BRAFis and UVB exposure on papillomavirus induced skin tumorigenesis was investigated in immunocompetent FVB/NCrl mice. Systemic BRAF inhibition in combination with UVB light induced skin tumors in 62% of the MmuPV1-infected animals. In contrast, significantly fewer tumors were observed in the absence of either BRAF inhibition, UVB irradiation or virus infection, as demonstrated by lesional outgrowth in 20%, 5% and 0% of the mice, respectively. Combinatory exposure to BRAFis and UVB favored productive viral infection, which was shown by high numbers of MmuPV1 genome copies and E1^E4 spliced transcripts and an abundance of E6/E7 oncogene mRNA and viral capsid proteins. BRAF inhibition, but not viral infection or UVB light, activated ERK1/2, whereas γH2AX expression, inducible by UVB light, remained unaltered by BRAFis. These results provide experimental evidence that BRAF inhibition and UVB irradiation synergistically promote MmuPV1-induced skin tumor development in vivo. This indicates an alternative pathway by which papillomavirus skin infection may contribute to BRAFi-associated skin tumorigenesis.

Green synthesis of polyethylene glycol coated, ciprofloxacin loaded CuO nanoparticles and its antibacterial activity against Staphylococcus aureus

Antibacterial resistance requires an advanced strategy to increase the efficacy of current therapeutics in addition to the synthesis of new generations of antibiotics. In this study, copper oxide nanoparticles (CuO-NPs) were green synthesized using Moringa oleifera root extract. CuO-NPs fabricated into a form of aspartic acid-ciprofloxacin-polyethylene glycol coated copper oxide-nanotherapeutics (CIP-PEG-CuO) to improve the antibacterial activity of NPs and the efficacy of the drug with controlled cytotoxicity. These NPs were charachterized by Fourier transform infrared spectroscopy (FTIR), x-rays diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Antibacterial screening and bacterial chemotaxis investigations demonstrated that CIP-PEG-CuO NPs show enhanced antibacterial potential against Gram-positive and Gram-negative clinically isolated pathogenic bacterial strains as compared to CuO-NPs. In ex-vivo cytotoxicity CIP-PEG-CuO-nano-formulates revealed 88% viability of Baby Hamster Kidney 21 cell lines and 90% RBCs remained intact with nano-formulations during hemolysis assay. An in-vivo studies on animal models show that Staphylococcus aureus were eradicated by this newly developed formulate from the infected skin and showed wound-healing properties. By using specially designed nanoparticles that are engineered to precisely transport antimicrobial agents, these efficient nano-drug delivery systems can target localized infections, ensure targeted delivery, enhance efficacy through increased drug penetration through physical barriers, and reduce systemic side effects for more effective treatment.

Hyaluronic Acid/Gelatin-Based Multifunctional Bioadhesive Hydrogel Loaded with a Broad-Spectrum Bacteriocin for Enhancing Diabetic Wound Healing.

The development of multifunctional wound adhesives is critical in clinical settings due to the scarcity of dressings with effective adhesive properties while protecting against infection by drug-resistant bacteria. Polysaccharide and gelatin-based hydrogels, known for their biocompatibility and bioactivity, assist in wound healing. This study introduces a multifunctional bioadhesive hydrogel developed through dynamic covalent bonding and light-triggered covalent bonding, comprising oxidized hyaluronic acid, methacrylated gelatin, and the bacteriocin recently discovered by our lab, named jileicin (JC). The adhesion strength of the hydrogel, measured at 180 kPa, was 4.35 times higher than that of the fibrin glue. Furthermore, the hydrogel demonstrated robust platelet adhesion, procoagulant activity, and outstanding hemostatic properties in a mouse liver injury model. Incorporating JC significantly enhanced the phagocytosis and bactericidal capabilities of the macrophages. This immunomodulatory function on host cells, coupled with its potent bacterial membrane-disrupting ability, makes JC an effective killer against methicillin-resistant Staphylococcus aureus. In wound repair experiments on diabetic mice with infected full-thickness skin defects, the hydrogel treatment group showed a notable reduction in bacterial load, accelerated M2-type macrophage polarization, diminished inflammation, and hastened wound healing. Owing to its outstanding biocompatibility, antibacterial activity, and controlled adhesion, this hydrogel presents a promising therapeutic option for treating infected skin wounds.

The role of male hormones in bacterial infections: enhancing Staphylococcus aureus virulence through testosterone-induced Agr activation.

Staphylococcus aureus is a notorious pathogen predominantly involved in skin and soft tissue infections, exhibiting a distinct innate sex bias. This study explores the influence of testosterone on the virulence of S. aureus and elucidates its underlying mechanisms. Utilizing a skin abscess model in intact and castrated male mice, we assessed the effects of testosterone on S. aureus pathogenicity. Compared to controls, castrated mice showed significantly reduced abscess sizes and decreased bacterial loads, highlighting the role of testosterone in modulating the severity of S. aureus infections. In vitro experiments revealed that testosterone enhances the hemolytic activity, cytotoxicity, and oxidative stress resistance of S. aureus. Real-time quantitative PCR analysis showed a significant upregulation of the genes encoding α-hemolysin (hla) and phenol-soluble modulin (psmα). Importantly, testosterone treatment significantly enhanced the expression of the accessory gene regulator (Agr) quorum-sensing system components (agrC, agrA, agrB, agrD), while the SaeRS system (saeR, saeS, and sbi) exhibited only slight changes. Gene knockout experiments revealed that deletion of agrC, rather than saeRS and agrBD, abolishes the testosterone-induced enhancement of hemolysis and gene expression, underscoring the key role of AgrC. Molecular docking simulations indicated a direct interaction between testosterone and AgrC protein, with a strong binding affinity at the active site residue SER201. This study provides new insights into the mechanistic basis of how testosterone enhances the pathogenicity of S. aureus, potentially contributing to increased male susceptibility to S. aureus infections and offering a targeted approach for therapeutic interventions.

In Vitro Anti-inflammatory Effects of Larch Turpentine, Turpentine Oil, Eucalyptus Oil, and Their Mixture as Contained in a Marketed Ointment.

An ointment containing larch turpentine, turpentine oil, and eucalyptus oil has been used for almost a century for the symptomatic treatment of mild, localized, purulent inflammations of the skin. Its clinical efficacy in the treatment of skin infections has been shown in clinical trials, but the mode of action of the active ingredients on inflammation is not known. We studied the anti-inflammatory properties of the active ingredients of the ointment and their mixture in a human monocyte cell model, in which the cells were stimulated with lipopolysaccharide and incubated with the test substances. The cytotoxic threshold of each test substance and the mixture was identified using the alamarBlue assay, and their anti-inflammatory activity was assessed by measuring the release of interleukins IL-1β, IL-6, IL-8, monocyte chemoattractant protein-1, prostaglandin E2, and TNF-α. Cell toxicity was observed at a mixture concentration of 10 µg/mL. All immunological assays were carried out at nontoxic concentrations. Larch turpentine decreased IL-1β, monocyte chemoattractant protein-1, and prostaglandin E2 release at a concentration of 3.9 µg/mL and TNF-α at concentrations > 1.95 µg/mL, whereas eucalyptus oil and turpentine oil had no relevant inhibitory effects. The mixture dose-dependently inhibited IL-1β, IL-6, monocyte chemoattractant protein-1, prostaglandin E2, and TNF-α release at concentrations > 1 µg/mL. IL-8 release was only marginally affected. The anti-inflammatory activity of the herbal ingredients and their mixture was confirmed in this model. This effect seems to be mediated mainly by larch turpentine, with turpentine oil and eucalyptus oil exerting an additive or possibly synergistic function.

Antibacterial and Anti-Inflammatory Activity of Branched Peptides Derived from Natural Host Defense Sequences.

Antibiotic resistance is a major global health threat, necessitating the development of new treatments and diverse molecules to combat severe infections and preserve the efficacy of existing drugs. Antimicrobial peptides (AMPs) offer a versatile arsenal against bacteria, and peptide structure branching can enhance their resistance to proteases and improve their overall efficacy. A small library of peptides derived from natural host defense peptides and synthesized in a tetrabranched form was selected against E. coli. Six selected branched peptides were further studied for antibacterial activity against a panel of strains, biofilm inhibition, protease resistance, and cytotoxicity. Their structure was predicted computationally and their mechanism of action was investigated by electron microscopy and by using fluorescent dyes. The peptide BAMP2 showed promise in a mouse skin infection model, indicating the potential for local infection treatment.

Impact of Extended Prophylactic Antibiotics on Risk of Prosthetic Joint Infection in Primary Total Hip Arthroplasty: A Matched Cohort Analysis.

Extended oral prophylactic antibiotics have been increasingly used in arthroplasty with the goal of reducing the risk of prosthetic joint infection (PJI). While a reduction in the rate of PJI has been noted with extended oral antibiotic regimens in high-risk patients, no large database study has assessed infection risk after primary total hip arthroplasty among well-balanced cohorts receiving and not receiving postoperative extended oral antibiotics. A retrospective cohort study was conducted using a national database, TriNetX, to identify patients who underwent primary total hip arthroplasty. This cohort was stratified by oral antibiotic prescription within one day of procedure. A one-to-one propensity score matching based on age, sex, class of obesity, and medical comorbidities was conducted. Outcomes explored in this study were 90-day risk of PJI, superficial skin infection, deep skin infection, and all-cause revision. 90-day postoperative infection complications of PJI were higher in the group receiving antibiotics (hazard ratio: 1.83, P-value = 0.012). Other complications such as superficial skin infection, deep skin infection, and all-cause revision showed no statistically significant differences. This database analysis of 5,476 patients demonstrated no decrease in complications of PJI, superficial or deep skin infection, or revision at 90 days. Future randomized controlled trials are needed to evaluate the efficacy of extended oral antibiotics. III.

Point-of-Care Ultrasound Diagnosis of Early Pyomyositis in a Pediatric Patient: A Case Report.

Skin and soft tissue infections are common in the pediatric emergency department. Because pyomyositis occurs deep to the fascial plane, it is often difficult to appreciate on physical examination. The utility of point-of-care ultrasound for identifying pyomyositis is of great value to the pediatric emergency physician as this diagnosis has a different expected clinical course and requires different management than other skin and soft tissue infections. This case report describes a child who presented to the pediatric emergency department with leg pain and redness, initially concerning for an abscess based on clinical findings. Point-of-care ultrasound diagnosed early pyomyositis, prompting early involvement of the pediatric surgical service and urgent computed tomography imaging, which confirmed the diagnosis.

The influence of marine fungal meroterpenoid meroantarctine A toward HaCaT keratinocytes infected with Staphylococcus aureus.

A new biological activity was discovered for marine fungal meroterpenoid meroantarctine A with unique 6/5/6/6 polycyclic system. It was found that meroantarctine A can significantly reduce biofilm formation by Staphylococcus aureus with an IC50 of 9.2 µM via inhibition of sortase A activity. Co-cultivation of HaCaT keratinocytes with a S. aureus suspension was used as an in vitro model of skin infection. Treatment of S. aureus-infected HaCaT cells with meroantarctine A at 10 µM caused a reduction in the production of TNF-α, IL-18, NO, and ROS, as well as LDH release and caspase 1 activation in these cells and, finally, recovered the proliferation and migration of HaCaT cells in an in vitro wound healing assay up to the control level. Thus, meroantarctine A is a new promising antibiofilm compound which can effective against S. aureus caused skin infection.

A specific and ultrasensitive Cas12a/crRNA assay with recombinase polymerase amplification and lateral flow biosensor technology for the rapid detection of Streptococcus pyogenes.

Patients may experience a range of symptoms due to Streptococcus pyogenes infections, including superficial skin infections, pharyngitis, and invasive diseases in subcutaneous tissues like streptococcal toxic shock syndrome. At present, the clinical diagnostic detection of S. pyogenes is based on serological identification, culture, and PCR. These detection methods are time-consuming and require sophisticated equipment, making these methods challenging for routine laboratories. Thus, there is a need for a detection platform that is capable of quickly and accurately identifying S. pyogenes. In this study, a rapid and sensitive Cas12a/crRNA assay using recombinase RPA and LFB was developed to detect S. pyogenes. The Cas12a/crRNA-based assay exhibited high specificity among different bacteria strains and extremely high sensitivity. This method probably plays an important role for S. pyogenes detection and screening.

Light‐Activated Nanocatalyst for Precise In‐Situ Antimicrobial Synthesis via Photoredox‐Catalytic Click Reaction

AbstractThe excessive and prolonged use of antibiotics contributes to the emergence of drug‐resistant S. aureus strains and potential dysbacteriosis‐related diseases, necessitating the exploration of alternative therapeutic approaches. Herein, we present a light‐activated nanocatalyst for synthesizing in situ antimicrobials through photoredox‐catalytic click reaction, achieving precise, site‐directed elimination of S. aureus skin infections. Methylene blue (MB), a commercially available photosensitizer, was encapsulated within the CuII‐based metal–organic framework, MOF‐199, and further enveloped with Pluronic F‐127 to create the light‐responsive nanocatalyst MB@PMOF. Upon exposure to red light, MB participates in a photoredox‐catalytic cycle, driven by the 1,3,5‐benzenetricarboxylic carboxylate salts (BTC−) ligand presented in the structure of MOF‐199. This light‐activated MB then catalyzes the reduction of CuII to CuI through a single‐electron transfer (SET) process, efficiently initiating the click reaction to form active antimicrobial agents under physiological conditions. Both in vitro and in vivo results demonstrated the effectiveness of MB@PMOF‐catalyzed drug synthesis in inhibiting S. aureus, including their methicillin‐resistant strains, thereby accelerating skin healing in severe bacterial infections. This study introduces a novel design paradigm for controlled, on‐site drug synthesis, offering a promising alternative to realize precise treatment of bacterial infections without undesirable side effects.

Exploring ethnic disparities in pediatric molluscum contagiosum in Southern Israel

Molluscum contagiosum (MC) is a common skin infection affecting children globally, including in Israel, which has a diverse population comprising mainly Jews (73.2%) and Arabs (21.1%). Despite documented disparities in various diseases between these groups, research on differences in dermatological care is scarce. This study aimed to investigate MC as a potential differentiator between Arab and Jewish children. A retrospective analysis of MC cases among children (0–18 years) from 2013 to 2022 was performed at Soroka University Medical Center, a tertiary hospital serving over a million patients. 615 patients participated in our study, with 95.2% Jewish and 4.8% Arab. Both groups showed similar characteristics in lesion quantity (P = 0.535), diameter (P = 0.341), inflammation markers, and lesion location. Additionally, management, treatment response, and outcomes were found to be similar between the two groups. In conclusion, the Arab representation in the study was disproportionately low compared to their population in the area. While Jewish patients may rely more on medical specialists, we believe Arabs may prefer self-management practices, such as the use of traditional medicine, possibly hindering effective physician-led care. Understanding such disparities could improve dermatological care by tailoring approaches to diverse populations.

Light-Activated Nanocatalyst for Precise In-Situ Antimicrobial Synthesis via Photoredox-Catalytic Click Reaction.

The excessive and prolonged use of antibiotics contributes to the emergence of drug-resistant S. aureus strains and potential dysbacteriosis-related diseases, necessitating the exploration of alternative therapeutic approaches. Herein, we present a light-activated nanocatalyst for synthesizing in situ antimicrobials through photoredox-catalytic click reaction, achieving precise, site-directed elimination of S. aureus skin infections. Methylene blue (MB), a commercially available photosensitizer, was encapsulated within the CuII-based metal-organic framework, MOF-199, and further enveloped with Pluronic F-127 to create the light-responsive nanocatalyst MB@PMOF. Upon exposure to red light, MB participates in a photoredox-catalytic cycle, driven by the 1,3,5-benzenetricarboxylic carboxylate salts (BTC-) ligand presented in the structure of MOF-199. This light-activated MB then catalyzes the reduction of CuII to CuI through a single-electron transfer (SET) process, efficiently initiating the click reaction to form active antimicrobial agents under physiological conditions. Both in vitro and in vivo results demonstrated the effectiveness of MB@PMOF-catalyzed drug synthesis in inhibiting S. aureus, including their methicillin-resistant strains, thereby accelerating skin healing in severe bacterial infections. This study introduces a novel design paradigm for controlled, on-site drug synthesis, offering a promising alternative to realize precise treatment of bacterial infections without undesirable side effects.