Citations

ABSTRACT Biofilms hinder wound infection healing, making wound infections a healthcare challenge for which innovative treatments are needed. A 1.77 cm 2 electrochemical bandage (e-bandage), which generates the biocide hypochlorous acid (HOCl), has shown promising anti-biofilm activity in vitro , ex vivo , and in vivo . The e-bandage is a three-electrode system operationalized by a hydrogel. In addition to providing a conductive electrolyte for the electrodes, the hydrogel provides a protective barrier for the wound. How different hydrogels impact e-bandage functionality is not completely defined. Here, the in vitro activity of seven clinically available hydrogels (xanthan gum, 3M, Duoderm, Prontosan, Purilon, Skintegrity, and Solosite) was evaluated with 1.77 cm 2 HOCl-generating e-bandages using a potentiostat with a multiplexer in a membrane biofilm model against methicillin-resistant Staphylococcus aureus IDRL-6169 and Acinetobacter baumannii ATCC-17978. When applied with polarized HOCl-producing e-bandages, all evaluated hydrogels except Solosite yielded ≥5.5 log 10 CFU/cm 2 reductions in bacterial quantities after 6 h of treatment, with most being below the detection limit at that time point. Prontosan exhibited antibacterial activity independent of e-bandage. Results of this study inform the selection of clinically available hydrogels that may be suitable for use with a 1.77 cm 2 HOCl-producing e-bandage. IMPORTANCE In this study, it was shown that some clinically available hydrogels, combined with a 1.77 cm 2 HOCl-generating electrochemical bandage, deliver time-dependent antimicrobial activity against methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii biofilms, offering a potential approach to treat wound infections, including those caused by antimicrobial-resistant bacteria.

SUMMARY Periprosthetic joint infection (PJI) is a significant complication of arthroplasty. Implicit in the diagnosis of PJI is the presence of organisms in what should be a sterile milieu. Given limits to culture-based PJI diagnosis, optimal utilization of culture in the diagnostic approach to PJI needs clarification. Culture is important in confirming a PJI diagnosis and characterizing the infecting microorganism(s) to inform management. As part of the development of a unified definition of PJI (by a group representing multiple scientific societies), a systematic review was performed to inform the role of culture in the definition of PJI. In addition, a comprehensive review on synovial fluid and periprosthetic tissue collection for culture, and associated culture methodology and results interpretation, was performed to inform best practices. Gaps in the literature were identified to develop research priorities.

ABSTRACT An electrochemical bandage (e‐bandage) that generates hydrogen peroxide (H 2 O 2 ) through a combination of working, counter and reference electrodes used with an electrolyte‐providing hydrogel is being developed for wound infection management. e‐Bandage biocidal activity was previously demonstrated using Xanthan gum hydrogel. For clinical use, clinically used hydrogels would be ideal, but their use with the described e‐bandage has not been shown. The goal of this work was to evaluate the biocidal activity of off‐the‐shelf, clinically used hydrogels when used with a 1.77 cm 2 H 2 O 2 ‐producing e‐bandage. e‐Bandage electrochemical parameters and activity against methicillin‐resistant Staphylococcus aureus IDRL‐6169 and Acinetobacter baumannii ATCC‐17978 biofilms were assessed with six off‐the‐shelf hydrogels. Variations in hydrogel composition affected electrochemical parameters, which was associated with differences in biocidal activity. Results of this study inform the selection of off‐the‐shelf hydrogels for use with H 2 O 2 ‐producing e‐bandages.

ABSTRACT Periprosthetic joint infection (PJI) is the most common and difficult to treat form of arthroplasty failure. While treatment with debridement, antibiotics, and implant retention (DAIR) is preferable to one- or two-stage implant exchange based on morbidity and cost, outcomes are not successful in all cases selected for this management strategy. DAIR is currently recommended when infection is perceived to be in an “acute” phase, based on symptom duration; despite this selection strategy, DAIR failure rates are high. A more objective means of predicting DAIR success could improve patient outcomes by limiting DAIR failures. To explore this possibility, advanced proteomic analysis of sonicate fluid samples from 95 subjects with PJI was performed using proximity extension assay (PEA), with 77 samples additionally undergoing complementary proteomics analysis with liquid chromatography with tandem mass spectrometry (LC-MS/MS). Sparse partial least squares differentiation analysis (sPLS-DA) separated samples from patients who underwent DAIR with known outcomes ( n = 19) into successful or unsuccessful groups, predicting DAIR surgical outcome (area under the curve [AUC]: 1; mean “leave one out” AUC: 0.6). Proteins predictive of DAIR surgical outcome were significantly enriched for the “protein repair” Gene Ontology (GO) pathway ( P -adj = 0.02). Additionally, proteomic signatures associated with symptom duration in PJI categorized samples into short and long symptom duration PJI. In summary, an investigation of 7,261 unique human proteins separated PJI-associated samples based on symptom duration and identified a proteomic profile predictive of DAIR success. IMPORTANCE Chronic infections are generally understood to last months to years, with acute infections lasting days to weeks. The transition from acute to chronic infection is, however, poorly understood. Periprosthetic joint infection (PJI) has been considered more challenging to treat when “chronic” than when “acute.” A surgery preferred for its recovery time and cost—debridement, antibiotics, and implant retention (DAIR)—is recommended for PJI management when symptom duration is short; yet, even in this select patient group, DAIR is associated with a high treatment failure rate. A means to better identify those predicted to have a successful outcome if they undergo DAIR is needed. Here, over 7,000 proteins from human clinical PJI samples were measured and shown to be able to separate samples based on symptom duration. Importantly, a proteomic profile predictive of DAIR success was identified.

ABSTRACT Periprosthetic joint infection (PJI) is a serious complication of total joint arthroplasty (TJA), with Staphylococcus aureus being one of the most common causative organisms. Irrigation and debridement with component retention (IDCR) is often performed to manage PJI. Antimicrobial treatment that targets S. aureus biofilms on prosthesis surfaces and within bone may be especially helpful when retaining a prosthesis. Phages, viruses that specifically infect bacteria, are a potential therapeutic consideration. Using a biofilm time kill assay in bovine synovial fluid, bactericidal activity of vancomycin or phage K (32 µg/mL and 10 11 pfu/mL, respectively) as well as the combination of phage K (10 10 pfu/mL) and vancomycin (32 µg/mL) was observed against a methicillin‐resistant S. aureus (MRSA) strain. Using a murine PJI model, mice infected with MRSA underwent IDCR followed by phage administration into the joint space with or without systemically administered vancomycin. Mice receiving both phage and vancomycin had significant reductions in MRSA on the prosthesis surface compared to untreated or vancomycin‐treated mice. Phage K showed bactericidal activity in vitro and was active when locally delivered in combination with systemically administered vancomycin in a murine PJI model managed with IDCR.

Abstract Background Central nervous system (CNS) infections are significant causes of morbidity and mortality, especially when diagnosis is delayed. Traditional cerebrospinal fluid diagnostic methods for CNS infections have limited sensitivity. Metagenomic next-generation sequencing of cerebrospinal fluid (MSCSF) is a newer diagnostic tool capable of detecting a broad range of pathogens in a single assay. Methods This retrospective cohort study evaluated the first-year experience with MSCSF at Mayo Clinic. A total of 422 tests performed during calendar year 2024 on adult patients at Mayo Clinic facilities and those tested through Mayo Clinic Laboratories were analyzed, with a subcohort analysis of the 210 Mayo Clinic patients performed to define patient characteristics associated with positive results and clinical outcomes. Results The sensitivity of MSCSF for detecting neuroinfection in the subcohort was 64%, with 43% of confirmed neuroinfections diagnosed by MSCSF only. Subjects who were immunosuppressed (odds ratio [OR]: 3.5, P = .008) and those with a high pretest probability of CNS infection (OR: 20.1, P < .001) were more likely to have positive results. Also, those who tested positive were more likely to die within the ensuing 30 days than those who tested negative (OR: 5.2, P = .001). Conclusions MSCSF can be a valuable tool for diagnosing CNS infection but should not be used indiscriminately. It appears to be most beneficial when there is a high clinical suspicion of CNS infection and conventional diagnostics, and available molecular tests, yield negative results. Its integration into clinical practice should be guided by diagnostic stewardship to maximize cost-effectiveness and clinical utility.

ABSTRACT Pneumonia may be caused by a diverse group of microorganisms; however, a microbiologic diagnosis is not universally made. Molecular tests such as the BIOFIRE FILMARRAY Pneumonia Panel (BF-PP) offer the possibility of rapid identification of potential pneumonia pathogens. This retrospective analysis was conducted as a sub-study of a recently published randomized controlled trial. Specimens from patients with suspected pneumonia were tested by the BF-PP, with results compared to cultures. The overall BF-PP positivity rate was 44.8% (252/563), and was higher [64.6% (164/254)] in specimens from patients ultimately diagnosed with pneumonia. Discrepancies between the BF-PP and cultures were most common for Streptococcus pneumoniae , Haemophilus influenzae , Moraxella catarrhalis, and Streptococcus agalactiae . Positive percent agreement (PPA) and negative percent agreement (NPA) between the BF-PP and culture were 91.4% (CI 86.3%–94.9%) and 83.6% (CI 79.5%–87.2%), respectively. For most bacteria, a correlation between high genomic abundance (genomic copies/mL) reported from the BF-PP and culture growth abundance was found. In specimens from patients ultimately diagnosed with pneumonia, clinical consistency—assessed based on whether BF-PP results aligned with associated culture results—was 79.9% and was highest for bronchoalveolar lavage fluid specimens. The BF-PP has reliable analytical performance and offers the potential advantage over conventional cultures of providing higher detection rates and more rapid results. Interestingly, despite the use of this advanced molecular diagnostic tool, one-third of pneumonia cases remained without a microbiologic etiology. IMPORTANCE This study evaluates the BIOFIRE FILMARRAY Pneumonia Panel by comparing its performance to conventional cultures in a real-world patient population (including patients ultimately diagnosed as not having pneumonia) using different types of specimens. Findings show a higher detection rate of microorganisms with the panel compared to cultures, suggesting that this test could aid in tailoring treatments for pneumonia. However, challenges remain and require further study, including distinguishing true pathogens from colonizing microorganisms and determinig why one-third of patients diagnosed with pneumonia still lacked a microbiologic etiology.

Background/Objectives: Staphylococci are the most common causes of periprosthetic joint infection (PJI); new antimicrobials are needed to manage these difficult infections. Nisin A is a lantibiotic peptide derived from Lactococcus lactis that has antimicrobial activity against Gram-positive bacteria, including staphylococci, and is an FDA-approved preservative used in the food and dairy industry. Here, the in vitro nisin A susceptibility of PJI-associated staphylococci was assessed. Methods: The minimum inhibitory concentrations (MICs), minimum biofilm inhibitory concentrations (MBICs), and minimum biofilm bactericidal concentrations (MBBCs) of nisin A were measured by broth microdilution against 106 staphylococcus isolates isolated from PJI. MICs were assessed using 5 × 105 CFU/mL plus nisin A. For MBICs, biofilms were grown on pegged lids for 6 h, followed by 20 h of treatment. For MBBCs, pegged lids were transferred to plates containing media only for 20 h. The results were determined as the lowest concentrations with no visual growth. Two-dimensional MICs with nisin A and vancomycin were assessed for 20 isolates. Fractional inhibitory concentrations (FICs) were calculated to determine synergistic, additive, antagonistic, or indifferent interactions. Results: The MIC that inhibited 90% of S. aureus and S. epidermidis was 4 µg/mL, apart from for the MRSA subset (8 µg/mL). The MBIC that inhibited 90% of isolates was 4 µg/mL. The MBBCs ranged from 4 to 256 µg/mL. When tested together, nisin A and vancomycin yielded an FIC between 1.25 and 1.5, indicative of indifference, except for one isolate each of MRSA and MSSA, for which an additive effect (FIC of 1) was observed. Conclusions: Nisin A showed inhibitory activity against staphylococci that cause PJI.

Abstract RATIONALE: Understanding co-isolation patterns between fungi and other potentially pathogenic microorganisms in the airways of bronchiectasis patients is important for uncovering possible microbial interactions and informing treatment. Although numerous organisms have been identified in respiratory cultures, the specific patterns of their co-isolation are underexplored. OBJECTIVES: To examine the patterns of co-isolation between fungi and bacteria or mycobacteria in respiratory samples from patients with bronchiectasis across a large national health system. METHODS: We reviewed 58,170 respiratory culture tests from 8,194 patients with bronchiectasis (identified using ICD-10-CM codes J47.0, J47.1, and J47.9) across Mayo Clinic. These tests were analyzed for fungal, bacterial, and mycobacterial growth, focusing on co-isolation from the same sample. Chi-square statistics were used to compute p-values. RESULTS: Of all 18,983 samples cultured for fungi, 59% were positive. Of these, 72% yielded yeasts and 40% molds. Among the 11,372 samples cultured for both fungi and bacteria, 681 (6%) showed co-isolation, representing 54% of positive bacterial cultures. The odds of bacterial co-isolation with fungi were 1.4 (95% CI: 1.3-1.6; p < 0.01), driven by yeasts (OR: 1.5, 95% CI: 1.3-1.7; p < 0.01), rather than molds (OR: 1.0, 95% CI: 0.9-1.2; p = 0.8). Pseudomonas species, the most common bacterial isolate, had a higher likelihood of co-isolation with fungi (OR: 1.6, 95% CI: 1.3-1.9; p < 0.01), particularly yeasts (OR: 1.6, 95% CI: 1.4-2.0; p < 0.01). Molds, including those from genera such as aspergillus and penicillium, did not show a significant association with the isolation of pseudomonas. On the other hand, among the 15,859 samples cultured for both fungi and mycobacteria, 1352 (9%) showed co-isolation, representing 62% of positive mycobacterial cultures. Odds of co-isolation were 1.7 (95% CI: 1.5-1.8; p < 0.01). Molds showed a stronger association with isolation of mycobacteria (OR: 1.7, 95% CI: 1.5-1.9; p < 0.01) compared to bacteria, while yeasts also had elevated odds (OR: 1.4, 95% CI: 1.2-1.5). CONCLUSIONS: Distinct patterns of fungal co-isolation with bacteria and mycobacteria have been observed in bronchiectasis, which may influence key aspects of the disease, such as inflammation and mucociliary dysfunction. Advanced metagenomic and immunoprofiling techniques could provide deeper insights into these co-isolation patterns while considering other factors like clinical demographics, previous antibiotic exposure, and disease severity. Understanding whether altering the mycobiome could modify these aspects and improve outcomes remains an important avenue for research.

ABSTRACT Contezolid has activity against methicillin-resistant Staphylococcus aureus (MRSA), a common cause of orthopedic infection. In a rat model of foreign body osteomyelitis, 1.3 log 10 cfu/g bone and 0.5 log 10 cfu/k-wire reduction in MRSA was found in tibiae ( P = 0.0186) and K-wires, respectively, of contezolid-treated compared to untreated rats. No MRSA was recovered from animals receiving rifampin alone or in combination with contezolid or vancomycin. There was no emergence of resistance to contezolid, vancomycin, or rifampin.