Subcutaneous Infection Research Articles

On-demand bactericidal and self-adaptive antifouling hydrogels for self-healing and lubricant coatings of catheters

Catheter-related infections are one of the most common nosocomial infections with increasing morbidity and mortality, and robust antibacterial or antifouling catheter coatings remain great challenges for long-term implantation. Herein, multifunctional hydrogel coatings were developed to provide persistent and self-adaptive antifouling and antibacterial effects with self-healing and lubricant capabilities. Polyvinyl alcohol (PVA) with β-cyclodextrin (β-CD) grafts (PVA-Cd) and 4-arm polyethylene glycol (PEG) with adamantane and quaternary ammonium compound (QAC) terminals (QA-PEG-Ad) were crosslinked through host-guest recognitions between adamantane and β-CD moieties to acquire PVEQ coatings. In response to bacterial infections, QACs exhibit reversible transformation between zwitterions (pH 7.4) and cationic lactones (pH 5.5) to generate on-demand bactericidal effect. Highly hydrophilic PEG/PVA backbones and zwitterionic QACs build a lubricate surface and decrease the friction coefficient 10 times compared with that of bare catheters. The antifouling hydrated layer significantly inhibits blood protein adsorption and platelet activation and reveals negligible hemolysis and cytotoxicity. The dynamic host-guest crosslinking achieves full self-healing of cracks in PVEQ hydrogels, and the mechanical profiles were recovered to over 90 % after rejuvenating the broken hydrogels, exhibiting a long-term stability after mechanical stretching, twisting, knotting and compression. After subcutaneous implantation and local bacterial infection, the retrieved PVEQ-coated catheters display no tissue adhesion and 3 log folds lower bacterial number than that of bare catheters. PVEQ coatings effectively prevent the repeated bacterial infections and there are few inflammatory reactions in the surrounding tissue, while substantial lymphoid infiltration and inflammatory cell aggregation occur in muscle tissues around the bare catheter. Thus, this study demonstrates a catheter coating strategy by on-demand bactericidal, self-adaptive antifouling, self-healing and lubricant hydrogels to address medical devices-related infections. Statement of significanceIt is estimated over two billion peripheral intravenous catheters are annually used in hospitals around the world, and catheter-associated infection has become a great clinical challenge with rapidly rising morbidity and mortality. Surface coating is considered a promising approach, but substantial challenges remain in the development of coatings that simultaneously satisfy both anti-fouling and antibacterial attributes. Even more, few attempts have been made to design mechanically robust coatings and reversible antibacterial or antifouling capabilities, which are critical for long-term medical implants. To address these challenges, we propose a concise strategy to develop hydrogel coatings from commercially available poly(ethylene glycol) and polyvinyl alcohol. In addition to self-healing and lubricant capabilities, the reversible conversion between zwitterionic and cationic lactones of quaternary ammonium compounds enables on-demand bactericidal and self-adaptive antifouling effects.

Effect of proton pump inhibitors on susceptibility and melanogenesis of Sporothrix species.

Introduction. Sporotrichosis is a subcutaneous infection caused by dimorphic Sporothrix species embedded in the clinical clade. Fungi have virulence factors, such as biofilm and melanin production, which contribute to their survival and are related to the increase in the number of cases of therapeutic failure, making it necessary to search for new options.Gap statement. Proton pump inhibitors (PPIs) have already been shown to inhibit the growth and melanogenesis of other fungi.Aim. Therefore, this study aimed to evaluate the effect of the PPIs omeprazole (OMP), rabeprazole (RBP), esomeprazole, pantoprazole and lansoprazole on the susceptibility and melanogenesis of Sporothrix species, and their interactions with itraconazole, terbinafine and amphotericin B.Methodology. The antifungal activity of PPIs was evaluated using the microdilution method, and the combination of PPIs with itraconazole, terbinafine and amphotericin B was assessed using the checkerboard method. The assessment of melanogenesis inhibition was assessed using grey scale.Results. The OMP and RBP showed significant MIC results ranging from 32 to 256 µg ml-1 and 32 to 128 µg ml-1, respectively. Biofilms were sensitive, with a significant reduction (P<0.05) in metabolic activity of 52% for OMP and 50% for RBP at a concentration of 512 µg ml-1 and of biomass by 53% for OMP and 51% for RBP at concentrations of 512 µg ml-1. As for the inhibition of melanogenesis, only OMP showed inhibition, with a 54% reduction.Conclusion. It concludes that the PPIs OMP and RBP have antifungal activity in vitro against planktonic cells and biofilms of Sporothrix species and that, in addition, OMP can inhibit the melanization process in Sporothrix species.

PET/CT Recognition of Costal Cartilage Infection After Breast Implant Surgery.

Postoperative infection of breast implants can lead to implant removal and other complications. This study aimed to investigate the presence of costal cartilage infection following breast implant surgery and the diagnostic role of PET/CT in identifying this rare complication. A retrospective study included 16 patients with persistent infections after breast implant removal surgery. Patients underwent PET/CT scans before surgery, and surgical plans were made based on PET/CT findings. Surgical procedures were guided by PET/CT, and specimens were collected for pathological examination and microbiological culture. Follow-up assessments were performed at 1, 3, and 12 months postoperatively. Among the 16 patients, 11 were diagnosed with costal cartilage infection, whereas 5 had subcutaneous soft tissue infections. PET/CT accurately identified costal cartilage infection in all cases and localized the infected costal cartilage in the majority of cases. Microbiological culture results showed various pathogens. All patients were cured with one or staged surgery. Costal cartilage infection following breast implant surgery is a significant concern. PET/CT plays a crucial role in the accurate diagnosis and localization of infected costal cartilage, aiding in appropriate surgical management. Patients should be closely monitored for the possibility of costal cartilage infection when experiencing persistent symptoms after breast implant surgery.

A Neglected Tropical Disease: Thoracic Actinomycetoma a Succesfull Case Report

Mycetoma is a chronic, granulomatous subcutaneous infection characterized by a triad of inflammation, painless tumour-like lesions and multiple sinuses discharging grains [1]. In Mexico, 97% of mycetomas are caused by bacteria of the order Actinomycetales, where Nocardia brasiliensis is the most important agent, while in eumycetomas the most important genera are Madurella spp. and Trematosphaeria spp [4]. This pathology is more common in men (3:1 to 5:1) between the age of 20 and 40 years, and up to 75% of patients present the injury (being the entry way) in the lower extremity, most commonly in the foot (70%). Other sites include the head, neck, chest, shoulders and arms [6, 7]. The diagnosis of mycetoma is based on clinical presentation, imaging studies and identification of the causative organisms in relevant clinical samples taken from affected tissues using fine-needle aspiration, or surgical biopsy. The diagnosis of mycetoma is based on clinical presentation, imaging studies and identification of the causative organisms in relevant clinical samples taken from affected tissues using fine-needle aspiration, or surgical biopsy. Imaging including X-ray, ultrasound, MRI and CT scan examinations may be required to characterize the spread and extent of disease [3].

Staphylococcus aureus wraps around Candida albicans and synergistically escapes from Neutrophil extracellular traps.

NETs, a unique neutrophil immune mechanism, are vital in defending against microbial invasions. Understanding the mechanisms of co-infection by Candida albicans and Staphylococcus aureus, which often leads to higher mortality and poorer prognosis, is crucial for studying infection progression. In our study, we established a mouse model of subcutaneous infection to characterize the inflammation induced by co-infection. By purifying and extracting NETs to interact with microorganisms, we delve into the differences in their interactions with various microbial species. Additionally, we investigated the differences in NETs production by neutrophils in response to single or mixed microorganisms through the interaction between neutrophils and these microorganisms. Furthermore, we analyzed the gene expression differences during co-infection using transcriptomics. In vivo, C. albicans infections tend to aggregate, while S. aureus infections are more diffuse. In cases of co-infection, S. aureus adheres to and wraps C. albicans. NETs exhibit strong killing capability against C. albicans but weaker efficacy against S. aureus. When NETs interact with mixed microorganisms, they preferentially target and kill the outer layer of S. aureus. In the early stages, neutrophils primarily rely on phagocytosis to kill S. aureus, but as the bacteria accumulate, they stimulate neutrophils to produce NETs. Interestingly, in the presence of neutrophils, S. aureus promotes the proliferation and hyphal growth of C. albicans. Our research has showed substantial differences in the progression of co-infections compared to single-microbial infections, thereby providing scientific evidence for NETs as potential therapeutic targets in the treatment of co-infections.

α-Hemolysin-mediated endothelial injury contributes to the development of Staphylococcus aureus-induced dermonecrosis.

Staphylococcus aureus α-hemolysin (Hla) is a pore-forming toxin critical for the pathogenesis of skin and soft tissue infections, which causes the pathognomonic lesion of cutaneous necrosis (dermonecrosis) in mouse models. To determine the mechanism by which dermonecrosis develops during S. aureus skin infection, mice were given control serum, Hla-neutralizing antiserum, or an inhibitor of Hla receptor [A-disintegrin and metalloprotease 10 (ADAM10) inhibitor] followed by subcutaneous infection by S. aureus, and the lesions were evaluated using immunohistochemistry and immunofluorescence. Hla induced apoptosis in the vascular endothelium at 6 hours post-infection (hpi), followed by apoptosis in keratinocytes at 24 hpi. The loss of vascular endothelial (VE)-cadherin expression preceded the loss of epithelial-cadherin expression. Hla also induced hypoxia in the keratinocytes at 24 hpi following vascular injury. Treatment with Hla-neutralizing antibody or ADAM10 inhibitor attenuated early cleavage of VE-cadherin, cutaneous hypoxia, and dermonecrosis. These findings suggest that Hla-mediated vascular injury with cutaneous hypoxia underlies the pathogenesis of S. aureus-induced dermonecrosis.

Fungal Musculoskeletal Infections: Comprehensive Approach to Proper Diagnosis.

Fungal musculoskeletal infections often have subacute or indolent manifestations, making it difficult to distinguish them from other diseases and infections, given that they are relatively uncommon. Fungal infections occur by hematogenous spread, direct inoculation, or contiguous extension and may be related to different risk factors, including immunosuppression and occupational activity. The infection can manifest in isolation in the musculoskeletal system or as part of a systemic process. The fungi may be endemic to certain regions or may be found throughout the world, and this can help to narrow the diagnosis of the etiologic agent. Infections such as candidiasis, cryptococcosis, aspergillosis, and mucormycosis are often related to immunosuppression. On the other hand, histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, and blastomycosis can occur in healthy patients in geographic areas where these infections are endemic. Furthermore, infections can be classified on the basis of the site of infection in the body. Some subcutaneous infections that can have osteoarticular involvement include mycetoma, sporotrichosis, and phaeohyphomycosis. Different fungi affect specific bones and joints with greater prevalence. Imaging has a critical role in the evaluation of these diseases. Imaging findings include nonspecific features such as osteomyelitis and arthritis, with bone destruction, osseous erosion, mixed lytic and sclerotic lesions, and joint space narrowing. Multifocal osteomyelitis and chronic arthritis with joint effusion and synovial thickening may also occur. Although imaging findings are often nonspecific, some fungal infections may show findings that aid in narrowing the differential diagnosis, especially when they are associated with the patient's clinical condition and history, the site of osteoarticular involvement, and the geographic location. ©RSNA, 2024.

To assess the diagnostic accuracy of LRINEC Score for prediction of necrotizing fasciitis in patients presenting with clinical skin and subcutaneous tissue infections

To assess the diagnostic accuracy of LRINEC Score for prediction of necrotizing fasciitis in patients presenting with clinical skin and subcutaneous tissue infections

Optimal Timing of Cranioplasty After Decompressive Craniectomy: Timing or Collapse Ratio.

Although cranioplasty (CP) is a relatively straightforward surgical procedure, it is associated with a high complication rate. The optimal timing for this surgery remains undetermined. This study aimed to identify the most suitable timing for CP to minimize postoperative complications. We conducted a retrospective analysis of all CP cases performed in our department from August 2015 to March 2022. Data were gathered through case statistics and categorized based on the occurrence of complications. The collapse ratio was determined using 3-dimensional Slicer software. In our retrospective study of 266 patients, 51 experienced postoperative complications, including hydrocephalus, epidural effusion, subdural hematoma, epilepsy, and subcutaneous infection. Logistic regression analysis identified independent predictors of postcranioplasty complications, and a nomogram was developed. The predictive value of the logistic regression model, collapse ratio, and decompression craniotomy-CP operation interval for post-skull repair complications was assessed using receiver operating characteristic curve analysis. No significant differences were observed in postoperative complications and decompression craniotomy-CP intervals between the groups (P = .07, P > .05). However, significant differences were noted in postoperative collapse ratios and CP complications between the groups (P = .023, P < .05). Logistic regression revealed that the collapse ratio (odds ratio = 1.486; 95% CI: 1.001-2.008; P = .01) and CP operation time (odds ratio = 1.017; 95% CI: 1.008-1.025, P < .001) were independent risk factors for postoperative complications. Receiver operating characteristic curve analysis indicated that the collapse ratio could predict CP postoperative complications, with a cutoff value of 0.274, an area under the curve of 0.621, a sensitivity of 62.75%, and a specificity of 63.26%. The post-skull repair collapse ratio is a significant predictor of postoperative complications. It is advisable to base the timing of surgery on the extent of brain tissue collapse, rather than solely on the duration between cranial decompression and CP.

The interferon-induced protein, IFIT2, requires RNA-binding activity and neuronal expression to protect mice from intranasal vesicular stomatitis virus infection.

The interferon (IFN) system protects mammals from diseases caused by virus infections. IFN synthesis is induced by pattern recognition receptor signaling pathways activated by virus infection. IFN is secreted from the infected cells and acts upon neighboring cells by binding cell surface receptors and triggering induction of hundreds of IFN-stimulated genes and proteins, many of which block different steps of virus replication. The IFN-induced tetratricopeptide repeat proteins (IFIT) are a family of RNA-binding proteins. We and others have previously reported that IFIT2 protects mice from many neurotropic RNA viruses; indeed, Ifit2-/- mice are very susceptible to intranasal or subcutaneous infections with vesicular stomatitis virus (VSV). Here, using a newly generated conditional knockout mouse, we report that ablation of Ifit2 expression only in neuronal cells was sufficient to render mice susceptible to neuropathogenesis caused by intranasal, but not subcutaneous, infection of VSV. Another genetically modified mouse line, expressing a mutant IFIT2 that cannot bind RNA, was as susceptible to VSV infection as Ifit2-/- mice. These results demonstrated that IFIT2 RNA-binding activity is essential for protecting mice against neurological diseases caused by intranasal infection of VSV.IMPORTANCEInterferon's (IFN's) antiviral effects are mediated by the proteins encoded by the interferon-stimulated genes. IFN-stimulated genes (IFIT2) is one such protein, which inhibits replication of many RNA viruses in the mouse brain and the resultant neuropathology. Our study sheds light on how IFIT2 works. By ablating Ifit2 expression only in neuronal cells, using a newly generated conditional knockout mouse line, we showed that Ifit2 induction in the neurons of the infected mouse was necessary for antiviral function of interferon. IFIT2 has no known enzyme activity; instead, it functions by binding to cellular or viral proteins or RNAs. We engineered a new mouse line that expressed a mutant IFIT2 that cannot bind RNA. These mice were very susceptible to infection with vesicular stomatitis virus indicating that the RNA-binding property of IFIT2 was essential for its antiviral function in vivo.

Flexible nanoplatform facilitates antibacterial phototherapy by simultaneously enhancing photosensitizer permeation and relieving hypoxia in bacterial biofilms

Antimicrobial phototherapy has gained recognition as a promising approach for addressing bacterial biofilms, however, its effectiveness is often impeded by the robust physical and chemical defenses of the biofilms. Traditional antibacterial nanoplatforms face challenges in breaching the extracellular polymeric substances barrier to efficiently deliver photosensitizers deep into biofilms. Moreover, the prevalent hypoxia within biofilms restricts the success of oxygen-reliant phototherapy. In this study, we engineered a soft mesoporous organosilica nanoplatform (SMONs) by incorporating polyethylene glycol (PEG), catalase (CAT), and indocyanine green (ICG), forming SMONs-PEG-CAT-ICG (SPCI). We compared the antimicrobial efficacy of SPCI with more rigid nanoplatforms. Our results demonstrated that unique flexible mechanical properties of SPCI enable it to navigate through biofilm barriers, markedly enhancing ICG penetration in methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Notably, in a murine subcutaneous MRSA biofilm infection model, SPCI showed superior biofilm penetration and pharmacokinetic benefits over its rigid counterparts. The embedded catalase in SPCI effectively converts excess H2O2 present in infected tissues into O2, alleviating hypoxia and significantly boosting the antibacterial performance of phototherapy. Both in vitro and in vivo experiments confirmed that SPCI surpasses traditional rigid nanoplatforms in overcoming biofilm barriers, offering improved treatment outcomes for infections associated with bacterial biofilms. This study presents a viable strategy for managing bacterial biofilm-induced diseases by leveraging the unique attributes of a soft mesoporous organosilica-based nanoplatform. Statement of significanceThis research introduces an innovative antimicrobial phototherapy soft nanoplatform that overcomes the inherent limitations posed by the protective barriers of bacterial biofilms. By soft nanoplatform with flexible mechanical properties, we enhance the penetration and delivery of photosensitizers into biofilms. The inclusion of catalase within this soft nanoplatform addresses the hypoxia in biofilms by converting hydrogen peroxide into oxygen in infected tissues, thereby amplifying the antibacterial effectiveness of phototherapy. Compared to traditional rigid nanoplatforms, this flexible nanoplatform not only promotes the delivery of therapeutic agents but also sets a new direction for treating bacterial biofilm infections, offering significant implications for future antimicrobial therapies.

Enhancing Early Detection of Necrotizing Soft Tissue Infections: The Role of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) Score.

Background There is great variation in the etiology, predisposing organisms, incidence, clinical characteristics, severity, and consequences of skin and/or subcutaneous tissue infections. Extensive necrosis of the subcutaneous tissues and fascia is a characteristic of necrotizing soft tissue infections, which are frequently deadly. To change the course of treatment, this study highlights the need to find a tool that can quickly and accurately identify patients with necrotizing fasciitis (NF) and assist in making an early treatment decision. Methodology A prospective evaluation of 30 individuals with soft tissue infections was conducted using the laboratory risk indicator for necrotizing fasciitis (LRINEC). The patients were classified as low, intermediate, and high risk for the start of NF based on their LRINEC score. To assess the importance of the LRINEC score in forecasting the start of NF and its clinical consequences, patients in each group underwent appropriate management and statistical analysis. Results This study included 28 males (93.3%) and two females (6.7%). The associated p-value, recorded as 0.039, signifies statistical significance in the observed area under the receiver operating characteristic (ROC) curve. The p-value in risk categorization was found to be 0.296, which suggests that LRINEC helps in risk categorization with 100% sensitivity when used as a screening tool. Conclusion The early detection of necrotizing soft tissue infections, such as NF, is vital. The LRINEC score, based on routine lab tests, accurately distinguishes these infections. With high sensitivity and significant p-values, it helps stratify patients, guiding timely interventions and saving lives.

Tocilizumab for advanced non-small cell lung cancer with concomitant inflammatory cachexia: A single-centre study.

2647 Background: Cancer cachexia significantly contributes to morbidity and mortality in patients with non-small cell lung cancer (NSCLC). Inflammatory pathways mediated by interleukin-6 play a crucial role in the development of cancer cachexia. This study aimed to investigate the use of tocilizumab, an anti-interleukin-6 receptor inhibitor, in the management of NSCLC with coexisting inflammatory cachexia. Methods: Data were collected from patients with NSCLC and concurrent inflammatory cachexia who received either tocilizumab plus anti-tumour therapy or anti-tumour therapy alone. The primary endpoints were overall survival (OS) and improved modified Glasgow Prognostic Score (mGPS) at week 12, while secondary endpoints included changes from baseline over 12 weeks in body weight, albumin, C-reactive protein and mGPS. Qualitative improvements in patient self-rated appetite and fatigue were reported as exploratory analysis. Results: The study included 49 patients diagnosed with NSCLC and coexisting inflammatory cachexia, of which 26 received tocilizumab in combination with anti-tumour therapy, and 23 received anti-tumour therapy alone. The tocilizumab group demonstrated a significantly longer median OS compared to the control group (15.1 vs. 3.2 months; hazard ratio 0.18, 95% confidence interval 0.08-0.38; p &lt; 0.001). The rate of patients surviving with mGPS improvement at week 12 was significantly higher in the tocilizumab group than in the control group (OR 168.7, 95% CI 16.3-1746.5; p &lt; 0.001). Over the 12-week period, significant improvements were observed in body weight, albumin, C-reactive protein, and mGPS in the tocilizumab group compared to the control group. Additionally, the tocilizumab group displayed significantly higher rates of improvement in appetite and fatigue. The incidence of grade 3 or higher adverse events was 34.6% in the tocilizumab group compared to 78.3% in the control group. Tocilizumab-related adverse events were observed in three patients (11.5%), including two cases of neutropenia and one case of skin and subcutaneous tissue infection. Conclusions: Tocilizumab demonstrated significant benefits in survival and various clinical parameters, including body weight, albumin, C-reactive protein, mGPS, and symptom burden in patients with NSCLC and concurrent inflammatory cachexia. Given the existing unmet medical need for effective interventions for cancer cachexia, tocilizumab may be considered as a potential treatment option.

In vitro and in vivo studies of a biodegradable Zn-4Ag-0.1Sc alloy with high strength-elongation product, cytocompatibility, osteogenic differentiation, and anti-infection properties for guided bone-regeneration membrane applications

Zinc-silver (Zn-Ag) alloys are generally promising guided bone-regeneration membrane (GBRM) materials due to their moderate degradability, osteogenic differentiation, and antibacterial properties. However, Zn-Ag alloys often display microstructural inhomogeneity and mechanical instability due to the formation of coarse Ag-rich second phases. In this study, Zn-4Ag and Zn-4Ag-0.1Sc (denoted ZA and ZAS, respectively) were comparatively investigated, and the ZAS exhibited a suitable degradation rate, high strength-elongation product, cytocompatibility, antibacterial capacity, and in vitro and in vivo osteogenic properties, making it highly appropriate for GBRM applications. Among all the as-cast and hot-rolled (HR) samples, the HR ZAS had the highest ultimate tensile strength of ∼260.5 MPa, tensile yield strength of ∼202.0 MPa, and elongation of ∼72.7%. The HR ZAS also exhibited a higher degradation rate of ∼36.5 µm/a in Hanks’ solution than those of the HR ZA, while its diluted extract was more cytocompatible and capable of osteogenic differentiation toward both MG-63 and MC3T3-E1 cells. The HR ZAS showed an exceptionally effective antibacterial ability against S. aureus in both in vitro antibacterial testing and in vivo subcutaneous infection models. Further, the HR ZAS demonstrated better osteogenic and histocompatibility properties than those of pure Zn in a rat skull defect model.

IL-10 inhibition during immunization improves vaccine-induced protection against Staphylococcus aureus infection.

Staphylococcus aureus is a major human pathogen. An effective anti-S. aureus vaccine remains elusive as the correlates of protection are ill-defined. Targeting specific T cell populations is an important strategy for improving anti-S. aureus vaccine efficacy. Potential bottlenecks that remain are S. aureus-induced immunosuppression and the impact this might have on vaccine-induced immunity. S. aureus induces IL-10, which impedes effector T cell responses, facilitating persistence during both colonization and infection. Thus, it was hypothesized that transient targeting of IL-10 might represent an innovative way to improve vaccine efficacy. In this study, IL-10 expression was elevated in the nares of persistent carriers of S. aureus, and this was associated with reduced systemic S. aureus-specific Th1 responses. This suggests that systemic responses are remodeled because of commensal exposure to S. aureus, which negatively implicates vaccine function. To provide proof of concept that targeting immunosuppressive responses during immunization may be a useful approach to improve vaccine efficacy, we immunized mice with T cell-activating vaccines in combination with IL-10-neutralizing antibodies. Blocking IL-10 during vaccination enhanced effector T cell responses and improved bacterial clearance during subsequent systemic and subcutaneous infection. Taken together, these results reveal a potentially novel strategy for improving anti-S. aureus vaccine efficacy.

A bioswitchable antibacterial strategy for the treatment of implant-associated infections

Implant-associated infection (IAI) remains a significant clinical challenge due to the increase of bacterial resistance and the presence of bacterial biofilm. Endowing implants with antibacterial properties and functionality by surface covalent immobilization of antimicrobial peptides (AMPs) is a highly promising approach, but suffers from poor antibacterial effect. In this study, a bioswitchable antibacterial system is flexibly designed and constructed for IAI therapy. A universal and functional coating is polymerized on the material surface by propionaldehyde plasma polymerization and then conjugated with LL-37, a human cathelicidin peptide, by Schiff base reaction. The release of LL-37 can be triggered by the acidic microenvironment results from bacterial metabolism and respiration. The conjugated LL-37 under physiological environment shows better biocompatibility than direct administration of LL-37, while responsive released LL-37 under acidic microenvironment exhibits preferrable antibacterial activity in comparison with unresponsive immobilization of LL-37. Besides, the bioswitchable coating exhibits variable immunomodulatory abilities. Further in vivo subcutaneous implant-associated infection model confirms the good protection against bacterial infection of bioswitchable antibacterial system. This design strategy of bioswitchable antibacterial system will provide a simple and universal approach for the prevention and therapy of implant-associated infection.

Antibiotic-loaded lactoferrin nanoparticles as a platform for enhanced infection therapy through targeted elimination of intracellular bacteria

Intracellular bacteria can multiply inside host cells and manipulate their biology, and the efficacy of traditional antibiotic drug therapy for intracellular bacteria is limited by inadequate drug accumulation. Fighting against these stealthy bacteria has been a long-standing challenge. Here, a system of stimuli-responsive lactoferrin (Lf) nanoparticles is prepared using protein self-assembly technology to deliver broad-spectrum antibiotic rifampicin (Rif) (Rif@Lf NPs) for enhanced infection therapy through targeted elimination of intracellular bacteria. Compared to Rif@BSA NPs, the Rif@Lf NPs can specifically target macrophages infected by bacteria, thus increasing the accumulation of Rif within macrophages. Subsequently, Rif@Lf NPs with positive surface charge further displayed targeted adherence to the bacteria within macrophages and released Rif rapidly in a redox-responsive manner. Combined with the antibacterial activities of Lf and Rif, the Rif@Lf NPs showed broad-spectrum antibiotic abilities to intracellular bacteria and biofilms. As a result, the Rif@Lf NPs with high safety exhibited excellent therapeutic efficacy in the disease models of subcutaneous infection, sepsis, and bacterial keratitis. Taken together, the antibiotic-loaded Lf nanoparticles present a promising platform to combat pathogen infections through targeted elimination of intracellular bacteria.

P172 An integrated safety analysis of treatment-emergent fungal infections in patients with psoriasis, psoriatic arthritis, or axial spondyloarthritis treated with ixekizumab from 26 clinical studies

Abstract Background/Aims Interleukin (IL)-17 plays a role in host defense against common extracellular pathogens, including fungi. Treatment with IL-17 inhibitors has been associated with fungal infections. Ixekizumab (IXE) is an anti-IL-17A monoclonal antibody approved for the treatment of psoriasis (PsO) in adults and children, psoriatic arthritis (PsA) in adults, and axial spondyloarthritis (axSpA) in adults. This integrated post-hoc analysis investigates treatment-emergent fungal infections in IXE-treated patients across the approved indications. Methods Safety data on fungal infections were pooled from the IXE paediatric and adult clinical trial programs, comprising 26 clinical studies. Here, we describe the types of fungal infections, number of infections, recurrence (defined by at least two separate events irrespective of location), severity (defined at the investigator’s discretion), events that lead to discontinuation, and anti-fungal medications. Data are presented as frequency or incidence rate per 100 person-years (IR). Results Fungal infections were reported in patients with PsO (IR = 4.0), PsA (IR = 4.1), and axSpA (IR = 2.7). Across indications, most fungal infections were not recurrent and were classified as mild or moderate in severity. There were few severe fungal infections in patients with PsO (IR = 0.1), PsA (IR = 0.0), and axSpA (IR = 0.0). Most fungal infections in patients with PsO, PsA, and axSpA were candidiasis (IR = 1.9, IR = 2.5, IR = 1.4, respectively) and superficial dermatophytosis (IR = 1.5, IR = 1.0, IR = 1.0, respectively). No cases of subcutaneous and systemic mycosis infections were reported. The proportions of patients with PsO, PsA, and axSpA who received a topical vs systemic anti-fungal medication were 53.6% vs 1.1%, 47.8% vs 0.0%, and 45.6% vs 3.5%, respectively (Table 1). Most fungal infections did not lead to discontinuation of IXE (Table 1). Conclusion Consistent with previously disclosed IXE data, the majority of treatment-emergent fungal infections observed in patients with PsO, PsA, or axSpA treated with IXE were: (i) not recurrent; (ii) mild or moderate in severity, (iii) associated with candidiasis and superficial dermatophytosis, (iv) managed with topical anti-fungal medications or no treatment reported, and (v) not leading to drug discontinuation. Disclosure S. Schwartzman: Corporate appointments; SS reports being a board member of the National Psoriasis Foundation. Consultancies; S. Schwartzman has served as a speaker and/or consultant for AbbVie, Janssen, Eli Lilly and Company, Pfizer, UCB, Myriad, Novartis, Regeneron, Sanofi, Stelexis, Jubilant, Teijin. L. Puig: Corporate appointments; Board member of the International Psoriasis Council. Consultancies; AbbVie, Almirall, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Janssen, Leo Pharma, Eli Lilly and Company, Novartis, Pfizer, Sandoz, Sanofi, UCB. Honoraria; Boehringer Ingelheim, Janssen, Eli Lilly and Company, Novartis, UCB, travel support from Janssen, Eli Lilly and Company, Pfizer, UCB. Grants/research support; L. Puig reports receiving grants from AbbVie, Almirall, Amgen, Boehringer Ingelheim, Leo Pharma, Eli Lilly and Company, Novartis, Pfizer, Sanofi, UCB. A.D. Cohen: Honoraria; AbbVie, Amgen, Boehringer Ingelheim, Dexcel Pharma; Janssen, Eli Lilly and Company, Neopharm, Novartis, Perrigo, Pfizer, Rafa. Grants/research support; A. D. Cohen has served on advisory board for Samsung, and reports receiving grants from AbbVie, Janssen, Novartis, Pfizer, travel support from AbbVie. S. Khattri: Consultancies; S. Khattri reports being part of Eli Lilly and Company speaker’s bureau, receiving consulting fees and honoraria from Eli Lilly and Company, AbbVie, UCB, Janssen, BI, Regeneron, Leo Pharma. C. Jossart: Shareholder/stock ownership; C. Jossart is a stockholder of Eli Lilly and Company and was an employee of Eli Lilly and Company when this study was conducted. C. Diaz: Shareholder/stock ownership; C. Diaz is employee and stockholder of Eli Lilly and Company. A. Garrelts: Shareholder/stock ownership; A. Garrelts is employee and stockholder of Eli Lilly and Company. D. Zhu: Shareholder/stock ownership; D. Zhu is employee and stockholder of Eli Lilly and Company. N. Eberhart: Shareholder/stock ownership; N. Eberhart is employee and stockholder of Eli Lilly and Company. A. Eleftheriadi: Shareholder/stock ownership; A. Eleftheriadi is employee and stockholder of Eli Lilly and Company. N. Tangsirisap: Shareholder/stock ownership; N. Tangsirisap is employee and stockholder of Eli Lilly and Company. C. Schuster: Shareholder/stock ownership; C. Schuster is an employee and stockholder of Eli Lilly and Company. A.B. Gottlieb: Consultancies; Xbiotech (stock options for an RA project). Honoraria; Amgen, AnaptysBio, Avotres Therapeutics, Boehringer Ingelheim, Bristol Myers Squibb, Dice Therapuetics, Dermavant, Lilly, Janssen, Leo, Pharma, Novartis, Pfizer, Sanofi, Sun Pharma, UCB Pharma. Grants/research support; AnaptysBio, Moonlake Immunotherapeutics, Novartis, BMS, and UCB Pharma; all funds go to the Icahn School of Medicine at Mount Sinai. M. Sheesh: Shareholder/stock ownership; MS is a full-time employee and minor share holder of Eli-Lilly and Company.

Dirofilaria sp. and Blood Meal Analysis in Mosquitoes Collected in Vojvodina and Mačva, and the First Report of Setaria tundra (Issaitshikoff & Rajewskaya, 1928) in Serbia.

Dirofilaria immitis and D. repens are the two most widespread and important species of mosquito-borne nematodes, posing a significant threat to veterinary health and particularly affecting canines and felines. While D. immitis causes cardiopulmonary dirofilariasis, D. repens causes subcutaneous infections in dogs and other carnivores. Despite the extensive knowledge on these parasites, little is known about their natural vectors in Serbia. The parasite Setaria tundra, known to infect deer, has not yet been detected in Serbia but has been documented in neighboring countries. Thus, the aim of this study was to (i) further map out Dirofilaria sp. hotspots in the Vojvodina Province and detect S. tundra for the first time, (ii) detect positive mosquito species that can provide insights into how the nematodes spread in Serbia, and (iii) analyze the blood-fed female mosquitoes of species found to be infected, in order to identify the potential source of parasite infection. A total of 2902 female mosquitoes were collected across 73 locations during 2021 and 2022. Molecular biology methods, based on conventional PCR, were used to analyze non-blood-fed (2521 specimens) and blood-fed (381 specimens) female mosquitos, in order to detect filarial nematode presence and identify blood-meal sources, respectively. When the parasite genome was detected, the amplicon (cox1 gene, 650 bp fragment) was sent for Sanger sequencing, further confirming the presence of nematodes and species assignation. D. immitis was detected in three Culex pipiens mosquitoes collected in Zrenjanin (August 2021) and Glogonj and Svetozar Miletić (both in July 2021). Additionally, Setaria tundra was detected in Aedes vexans collected in Iđoš (mid-August 2021) and Aedes caspius, which was collected in Mali Iđoš (end of July 2021). This work identifies two new locations where D. immitis occurs in Vojvodina, and is the first report of S. tundra in Serbian territory. Blood-meal analysis provided insights into the preferences of mosquitoes that were positive for Dirofilaria sp. and S. tundra.

Silencing of Sporothrix schenckii GP70 Reveals Its Contribution to Fungal Adhesion, Virulence, and the Host-Fungus Interaction.

Sporothrix schenckii is one of the etiological agents of sporotrichosis, a cutaneous and subcutaneous infection distributed worldwide. Like other medically relevant fungi, its cell wall is a molecular scaffold to display virulence factors, such as protective pigments, hydrolytic enzymes, and adhesins. Cell wall proteins with adhesive properties have been previously reported, but only a handful of them have been identified and characterized. One of them is Gp70, an abundant cell wall protein mainly found on the surface of yeast-like cells. Since the protein also has a role in the activity of 3-carboxy-cis,cis-muconate cyclase and its abundance is low in highly virulent strains, its role in the Sporothrix-host interaction remains unclear. Here, a set of GP70-silenced strains was generated, and the molecular and phenotypical characterization was performed. The results showed that mutants with high silencing levels showed a significant reduction in the adhesion to laminin and fibrinogen, enzyme activity, and defects in the cell wall composition, which included reduced mannose, rhamnose, and protein content, accompanied by an increment in β-1,3-glucans levels. The cell wall N-linked glycan content was significantly reduced. These strains induced poor TNFα and IL-6 levels when interacting with human peripheral blood mononuclear cells in a dectin-1-, TLR2-, and TLR4-dependent stimulation. The IL-1β and IL-10 levels were significantly higher and were stimulated via dectin-1. Phagocytosis and stimulation of neutrophil extracellular traps by human granulocytes were increased in highly GP70-silenced strains. Furthermore, these mutants showed virulence attenuation in the invertebrate model Galleria mellonella. Our results demonstrate that Gp70 is a versatile protein with adhesin properties, is responsible for the activity of 3-carboxy-cis,cis-muconate cyclase, and is relevant for the S. schenckii-host interaction.