Fecal microbiota transplantation (FMT) is an emerging therapy for recurrent or refractory
infection and is being actively investigated for other conditions. We describe two patients in whom ...extended-spectrum beta-lactamase (ESBL)-producing
bacteremia occurred after they had undergone FMT in two independent clinical trials; both cases were linked to the same stool donor by means of genomic sequencing. One of the patients died. Enhanced donor screening to limit the transmission of microorganisms that could lead to adverse infectious events and continued vigilance to define the benefits and risks of FMT across different patient populations are warranted.
Neutrophils employ several mechanisms to restrict fungi, including the action of enzymes such as myeloperoxidase (MPO) or NADPH oxidase, and the release of neutrophil extracellular traps (NETs). ...Moreover, they cooperate, forming "swarms" to attack fungi that are larger than individual neutrophils. Here, we designed an assay for studying how these mechanisms work together and contribute to neutrophil's ability to contain clusters of live Candida. We find that neutrophil swarming over Candida clusters delays germination through the action of MPO and NADPH oxidase, and restricts fungal growth through NET release within the swarm. In comparison with neutrophils from healthy subjects, those from patients with chronic granulomatous disease produce larger swarms against Candida, but their release of NETs is delayed, resulting in impaired control of fungal growth. We also show that granulocyte colony-stimulating factors (GCSF and GM-CSF) enhance swarming and neutrophil ability to restrict fungal growth, even during treatment with chemical inhibitors that disrupt neutrophil function.
Hematopoietic stem cell transplantation (HSCT) is a curative therapy for blood and immune diseases with potential for many settings beyond current standard-of-care. Broad HSCT application is ...currently precluded largely due to morbidity and mortality associated with genotoxic irradiation or chemotherapy conditioning. Here we show that a single dose of a CD117-antibody-drug-conjugate (CD117-ADC) to saporin leads to > 99% depletion of host HSCs, enabling rapid and efficient donor hematopoietic cell engraftment. Importantly, CD117-ADC selectively targets hematopoietic stem cells yet does not cause clinically significant side-effects. Blood counts and immune cell function are preserved following CD117-ADC treatment, with effective responses by recipients to both viral and fungal challenges. These results suggest that CD117-ADC-mediated HSCT pre-treatment could serve as a non-myeloablative conditioning strategy for the treatment of a wide range of non-malignant and malignant diseases, and might be especially suited to gene therapy and gene editing settings in which preservation of immunity is desired.
Hematopoietic stem cell transplantation (HSCT) offers curative therapy for patients with hemoglobinopathies, congenital immunodeficiencies, and other conditions, possibly including AIDS. Autologous ...HSCT using genetically corrected cells would avoid the risk of graft-versus-host disease (GVHD), but the genotoxicity of conditioning remains a substantial barrier to the development of this approach. Here we report an internalizing immunotoxin targeting the hematopoietic-cell-restricted CD45 receptor that effectively conditions immunocompetent mice. A single dose of the immunotoxin, CD45-saporin (SAP), enabled efficient (>90%) engraftment of donor cells and full correction of a sickle-cell anemia model. In contrast to irradiation, CD45-SAP completely avoided neutropenia and anemia, spared bone marrow and thymic niches, enabling rapid recovery of T and B cells, preserved anti-fungal immunity, and had minimal overall toxicity. This non-genotoxic conditioning method may provide an attractive alternative to current conditioning regimens for HSCT in the treatment of non-malignant blood diseases.
While short lived, neutrophils rapidly deploy a variety of mechanisms to eradicate microbial pathogens including phagocytosis, the release of antimicrobial peptides, the production of reactive oxygen ...species (ROS), the formation of neutrophil extracellular traps (NETs), and the secretion of cytokines and chemokines. Additionally, neutrophils maintain a wide breadth of roles in homeostasis, including the clearance of necrotic tissue, and in disease where they become a source of damaging inflammation 1,2. Because of this functional plasticity in both homeostasis and infection, neutrophils are hypothesized to exist as unique, diverse subsets of heterogeneous populations of cells. GMP, granulocyte monocyte progenitor; PMN, polymorphonuclear leukocyte. https://doi.org/10.1371/journal.ppat.1009691.g001 Mouse neutrophil populations have now been characterized by single-cell transcriptomics during homeostasis and bacterial infection; authors were able to link specific cells from mouse peripheral blood, spleen, and bone marrow with previously described stages of neutrophil development based on classical cell morphology 16. Neutrophils demonstrate transcriptionally distinct subpopulations with differences in interferon-stimulated gene expression, lipopolysaccharide-mediated signaling pathways, as well as others 16.
Neutrophils are classically defined as terminally differentiated, short-lived cells; however, neutrophils can be long-lived with phenotypic plasticity. During inflammation, a subset of neutrophils ...transdifferentiate into a population called neutrophil-DC hybrids (PMN-DCs) having properties of both neutrophils and dendritic cells. While these cells ubiquitously appear during inflammation, the role of PMN-DCs in disease remains poorly understood. We observed the differentiation of PMN-DCs in pre-clinical murine models of fungal infection: blastomycosis, aspergillosis and candidiasis. Using reporter strains of fungal viability, we found that PMN-DCs associate with fungal cells and kill them more efficiently than undifferentiated canonical neutrophils. During pulmonary blastomycosis, PMN-DCs comprised less than 1% of leukocytes yet contributed up to 15% of the fungal killing. PMN-DCs displayed higher expression of pattern recognition receptors, greater phagocytosis, and heightened production of reactive oxygen species compared to canonical neutrophils. PMN-DCs also displayed prominent NETosis. To further study PMN-DC function, we exploited a granulocyte/macrophage progenitor (GMP) cell line, generated PMN-DCs to over 90% purity, and used them for adoptive transfer and antigen presentation studies. Adoptively transferred PMN-DCs from the GMP line enhanced protection against systemic infection in vivo. PMN-DCs pulsed with antigen activated fungal calnexin-specific transgenic T cells in vitro and in vivo, promoting the production of interferon-γ and interleukin-17 in these CD4+ T cells. Through direct fungal killing and induction of adaptive immunity, PMN-DCs are potent effectors of antifungal immunity and thereby represent innovative cell therapeutic targets in treating life-threatening fungal infections.
Procalcitonin is a biomarker that supports clinical decision-making on when to initiate and discontinue antibiotic therapy. Several cost (-effectiveness) analyses have been conducted on ...Procalcitonin-guided antibiotic stewardship, but none mainly based on US originated data.
To compare effectiveness and costs of a Procalcitonin-algorithm versus standard care to guide antibiotic prescription for patients hospitalized with a diagnosis of suspected sepsis or lower respiratory tract infection in the US.
A previously published health economic decision model was used to compare the costs and effects of Procalcitonin-guided care. The analysis considered the societal and hospital perspective with a time horizon covering the length of hospital stay. The main outcomes were total costs per patient, including treatment costs and productivity losses, the number of patients with antibiotic resistance or C.difficile infections, and costs per antibiotic day avoided.
Procalcitonin -guided care for hospitalized patients with suspected sepsis and lower respiratory tract infection is associated with a reduction in antibiotic days, a shorter length of stay on the regular ward and the intensive care unit, shorter duration of mechanical ventilation, and fewer patients at risk for antibiotic resistant or C.difficile infection. Total costs in the Procalcitonin-group compared to standard care were reduced by 26.0% in sepsis and 17.7% in lower respiratory tract infection (total incremental costs of -$11,311 per patient and -$2,867 per patient respectively).
Using a Procalcitonin-algorithm to guide antibiotic use in sepsis and hospitalised lower respiratory tract infection patients is expected to generate cost-savings to the hospital and lower rates of antibiotic resistance and C.difficile infections.
As the leading cause of fungal skin infections around the globe, dermatophytes are responsible for a multitude of skin ailments, ranging from athlete’s foot to ringworm. Due to the combination of its ...growing prevalence and antifungal misuse, antifungal-resistant dermatophyte strains like Trichophyton indotineae have begun to emerge, posing a significant global health risk. The emergence of these resistant dermatophytes highlights a critical need to identify alternative methods of treating dermatophyte infections. In our study, we utilized a 405 nm LED to establish that blue light can effectively inactivate catalase within a variety of both susceptible and resistant dermatophytes. Through this catalase inactivation process, light-treated dermatophytes were found to exhibit increased sensitivity to reactive oxygen species (ROS)-producing agents, improving the performance of antimicrobial agents such as H2O2 and amphotericin B. Our findings further demonstrate that light-induced catalase inactivation can inhibit the formation and polarized growth of hyphae from dermatophytes, suppressing biomass formation. Thus, by increasing ROS sensitization and inhibiting hyphal development, catalase-deactivating blue light offers a potential non-invasive and non-drug-reliant method of managing dermatophyte infections, opening new avenues for the potential treatment of these common infections in conjunction with existing treatments.
Natural killer (NK) cells use the activating receptor NKp30 as a microbial pattern-recognition receptor to recognize, activate cytolytic pathways, and directly kill the fungi Cryptococcus neoformans ...and Candida albicans. However, the fungal pathogen-associated molecular pattern (PAMP) that triggers NKp30-mediated killing remains to be identified. Here we show that β-1,3-glucan, a component of the fungal cell wall, binds to NKp30. We further demonstrate that β-1,3-glucan stimulates granule convergence and polarization, as shown by live cell imaging. Through Src Family Kinase signaling, β-1,3-glucan increases expression and clustering of NKp30 at the microbial and NK cell synapse to induce perforin release for fungal cytotoxicity. Rather than blocking the interaction between fungi and NK cells, soluble β-1,3-glucan enhances fungal killing and restores defective cryptococcal killing by NK cells from HIV-positive individuals, implicating β-1,3-glucan to be both an activating ligand and a soluble PAMP that shapes NK cell host immunity.
PDF
