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Scedosporium species rank second among the filamentous fungi capable to colonize chronically the respiratory tract of patients with cystic fibrosis (CF). Nevertheless, there is little information on the mechanisms underpinning their virulence. Iron acquisition is critical for the growth and pathogenesis of many bacterial and fungal genera that chronically inhabit the CF lungs. In a previous study, we showed the presence in the genome of Scedosporium apiospermum of several genes relevant for iron uptake, notably SAPIO_CDS2806, an ortholog of sidD , which drives the synthesis of the extracellular hydroxamate-type siderophore fusarinine C (FsC) and its derivative triacetylfusarinine C (TAFC) in Aspergillus fumigatus . Here, we demonstrate that Scedosporium apiospermum sidD gene is required for production of an excreted siderophore, namely, N α -methylcoprogen B, which also belongs to the hydroxamate family. Blockage of the synthesis of N α -methylcoprogen B by disruption of the sidD gene resulted in the lack of fungal growth under iron limiting conditions. Still, growth of ΔsidD mutants could be restored by supplementation of the culture medium with a culture filtrate from the parent strain, but not from the mutants. Furthermore, the use of xenosiderophores as the sole source of iron revealed that S. apiospermum can acquire the iron using the hydroxamate siderophores ferrichrome or ferrioxamine, i.e., independently of N α -methylcoprogen B production. Conversely, N α -methylcoprogen B is mandatory for iron acquisition from pyoverdine, a mixed catecholate-hydroxamate siderophore. Finally, the deletion of sidD resulted in the loss of virulence in a murine model of scedosporiosis. Our findings demonstrate that S. apiospermum sidD gene drives the synthesis of a unique extracellular, hydroxamate-type iron chelator, which is essential for fungal growth and virulence. This compound scavenges iron from pyoverdine, which might explain why S. apiospermum and Pseudomonas aeruginosa are rarely found simultaneously in the CF lungs., (Copyright © 2020 Le Govic, Havlíček, Capilla, Luptáková, Dumas, Papon, Le Gal, Bouchara and Vandeputte.)

Invasive pulmonary aspergillosis represents one of the most serious fungal infections among immunocompromised patients. In this study, we aimed to analyze the in vivo efficacy of prophylactic oral amphotericin B (AMB) encapsulated in modified chitosan-nanoparticles (Nanomerics' Molecular Envelope Technology (MET)) supplemented with a standardized extract of cultured Lentinula edodes mycelia (AHCC ® ) in a murine model of pulmonary aspergillosis. We determined fungal burden and survival of mice and additionally, we carried out a cytokine analysis in an attempt to understand the immunomodulation of the extract. Our results evidenced equivalent efficacy between orally administered AMB-MET and the intravenous liposomal AMB marketed formulation. Addition of the AHCC ® supplement significantly improved efficacy in terms of burden reduction and survival increase of both oral and intravenous AMB therapies compared to the untreated control group. Moreover, a protective effect of the extract was observed in terms of weight loss. Regarding the cytokine profiles, the Th1 immune response was stimulated in treated animals when compared to the control group. This response was marked by an enhancement in the MCP-1, GM-CSF, VEGF, RANTES and IL-17 levels and a decrease in the IL-6, a biomarker related to the severity of the infection.

Fusaric acid (FA) is amongst the oldest identified secondary metabolites produced by Fusarium species, known for a long time to display strong phytotoxicity and moderate toxicity to animal cells; however, the cellular targets of FA and its function in fungal pathogenicity remain unknown. Here, we investigated the role of FA in Fusarium oxysporum, a soil-borne cross-kingdom pathogen that causes vascular wilt on more than 100 plant species and opportunistic infections in humans. Targeted deletion of fub1, encoding a predicted orthologue of the polyketide synthase involved in FA biosynthesis in F. verticillioides and F. fujikuroi, abolished the production of FA and its derivatives in F. oxysporum. We further showed that the expression of fub1 was positively controlled by the master regulator of secondary metabolism LaeA and the alkaline pH regulator PacC through the modulation of chromatin accessibility at the fub1 locus. FA exhibited strong phytotoxicity on tomato plants, which was rescued by the exogenous supply of copper, iron or zinc, suggesting a possible function of FA as a chelating agent of these metal ions. Importantly, the severity of vascular wilt symptoms on tomato plants and the mortality of immunosuppressed mice were significantly reduced in fub1Δ mutants and fully restored in the complemented strains. Collectively, these results provide new insights into the regulation and mode of action of FA, as well as on the function of this phytotoxin during the infection process of F. oxysporum., (© 2017 BSPP AND JOHN WILEY & SONS LTD.)

Aspergillus fumigatus is the main mold causing invasive fungal infection that shows high mortality rates. Therapeutic failure and the increase in drug resistance make it necessary to explore alternative treatments for this infection. We have evaluated the efficacy of amphotericin B at 0.8 mg/kg or 0.3 mg/kg of body weight combined with 40 mg/kg of posaconazole against three A. fumigatus isolates in a murine model of disseminated infection. The combination of the polyene and the azole led to a greater increase in survival and a significantly greater reduction in tissue burden than monotherapies., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

It has been argued that the in vitro activity of caspofungin (CSP) is not a good predictor of the outcome of echinocandin treatment in vivo. We evaluated the in vitro activity of CSP and the presence of FKS mutations in the hot spot 1 (HS1) region of the FKS1 and FKS2 genes in 17 Candida glabrata strains with a wide range of MICs. The efficacy of CSP against systemic infections from each of the 17 strains was evaluated in a murine model. No HS1 mutations were found in the eight strains showing MICs for CSP of ≤ 0.5 μg/ml, but they were present in eight of the nine strains with MICs of ≥ 1 μg/ml, i.e., three in the FKS1 gene and five in the FKS2 gene. CSP was effective for treating mice infected with strains with MICs of ≤ 0.5 μg/ml, showed variable efficacy in animals challenged with strains with MICs of 1 μg/ml, and did not work in those with strains with MICs of >1 μg/ml. In addition, mutations, including one reported for the first time, were found outside the HS1 region in the FKS2 gene of six strains with different MICs, but their presence did not influence drug efficacy. The in vitro activity of CSP was compared with that of another echinocandin, anidulafungin, suggesting that the MICs of both drugs, as well as mutations in the HS1 regions of the FKS1 and FKS2 genes, are predictive of outcome., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

The combination of amphotericin B at a suboptimal dose (0.3 mg/kg) with voriconazole has shown efficacy in prolonging survival and reducing tissue burden in a murine model of disseminated infection by an isolate of Aspergillus fumigatus that had showed a poor in vivo response to the azole. The efficacy of the combined treatment was higher than that obtained with amphotericin B at 0.8 mg/kg., (Copyright © 2013, American Society for Microbiology. All Rights Reserved.)

Objectives: A murine model of chromoblastomycosis caused by Cladophialophora carrionii was used to compare the efficacy of posaconazole and voriconazole with that of terbinafine and itraconazole, the currently used drugs in the management of chromoblastomycosis., Methods: Athymic nude mice were infected with 2 × 10(7) cfu of a clinical isolate of C. carrionii. When typical lesions were established, treatments with posaconazole at 20 mg/kg/day, voriconazole at 20 mg/kg/day, itraconazole at 50 mg/kg/day or terbinafine at 250 mg/kg/day were initiated. Treatment efficacy was evaluated for 4 months by measuring the size of the lesions, observing any histopathological changes and culturing the excised tissue., Results: Posaconazole was the only drug that reduced the initial lesion size, while voriconazole and terbinafine reduced growth relative to controls., Conclusions: This study suggests that the newer triazoles have potential in the treatment of chromoblastomycosis caused by C. carrionii.

The mortality of clinical Aspergillus infections necessitates consideration of the utility of a vaccine. We have found that Saccharomyces species can act as a protective vaccine against a lethal systemic Aspergillus infection, and describe experiments optimizing a subcutaneous regimen with killed yeast. Three injections of 2.5 mg given a week apart, 2 weeks prior to challenge, consistently, significantly, provided survival protection and reduction of infection in organs in survivors. The protection was independent of the strain of Saccharomyces, and possibly even the species, and could be demonstrated in several inbred (including C'-deficient) and outbred mouse strains. The protective moiety(ies) appeared to reside in the cell wall and was resistant to 100 °C, but not to protease or formalin. Alum potentiated the protection. The protection was comparable or superior to that of several Aspergillus-specific preparations described in the literature. Other studies have indicated that heat-killed Saccharomyces can protect against infection with at least three other fungal genera, raising the possibility of development of a panfungal vaccine, and such a vehicle has been studied in clinical trials, without dose-limiting toxicity.

Using a murine model of disseminated infection by Fusarium verticillioides, the efficacy of liposomal amphotericin (L-AmB) B at 10mg/kg body weight once daily and terbinafine (TRB) at 150 mg/kg body weight twice daily, alone and in combination, was evaluated. The combination of L-AmB with TRB was the only treatment able to prolong survival and to reduce fungal loads in the spleen and kidneys of mice infected with either strain of F. verticillioides used. The results suggest that this combination may have a role in the treatment of F. verticillioides infection., (Copyright © 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)

Background: Mixed fungal infections although undervalued, are more common than mentioned in the scientific literature. These infections have a poor prognosis for the patient., Objectives: We present an unusual case of a 61-year-old diabetic male who had a rhino-orbito-sinusal zygomycosis in 2001. After surgical debridement of the infected parts, along with antifungal therapy with liposomal amphotericin B, the patient started improving. Several years later the patient was hospitalized due to a similar problem and was diagnosed of rhino-orbito-cerebral zygomycosis., Methods: In both episodes, a histopathological examination and cultures were performed on the sinus lesions. Tissue sections were stained with haematoxylin and eosin, Giemsa, periodic acid-Schiff (PAS) and Grocott's methenamine silver, and cultures specific for fungi were performed., Results: The histopathology studies revealed the presence of bacteria, actinomyces and a mixed infection by at least four different fungi, all of them well differentiated by their morphology. Despite the rapid diagnosis the patient died due to spreading to the central nervous system., Conclusions: Mixed infections by fungi are rare, but due to the high incidence of immunodeficiencies they could occur more often than reported. We would like to alert on the possibility of acquired mixed infection by fungi which have shown to be high aggressive and have a worse prognostic in patients with underlying diseases., (Copyright © 2010 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.)

The perineural spread by fungal cells during the progression of the infection could be an important prognostic factor, especially in mycoses localized in the rhino-orbito-cerebral and pulmonary areas. We present a clinical case of a 73-year-old male, with diabetes and acute myelomonocytic leukaemia that began with tumefaction on the left side of his face, spreading to the sinus with invasion of the soft tissues and fistulae in the oral cavity. Clinical examination showed cerebral involvement. The histopathological sections and the histochemical techniques showed perineural involvement by fungal cells. Although the patient was diagnosed and treated in a short period of time, he died due to the infection. We would like to alert that perineural spread could be a retrograde way of mycoses dissemination, particularly in infections located in areas rich in neural cells., (Copyright 2009 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.)

Objectives: We compared the efficacy of treatments in a rabbit model of coccidioidal meningitis (CM)., Methods: Rabbits were infected intracisternally with Coccidioides immitis and treated with intravenous amphotericin B lipid complex (ABLC), deoxycholate amphotericin B (dAMB), oral fluconazole or diluent [sterile 5% dextrose in water (D5W)]. Survival and cfu in brain, spinal cord and CSF were determined and histology studied. Amphotericin B (AMB) concentrations in serum, CSF and tissue were determined by bioassay., Results: Fluconazole-treated rabbits and controls lost weight and had decreased mobility. All treatments prolonged survival (P = 0.005) and reduced cfu in brain and spinal cord (P

Experimental models of coccidioidomycosis performed using various laboratory animals have been, and remain, a critical component of elucidation and understanding of the pathogenesis and host resistance to infection with Coccidioides spp., as well as to development of more efficacious antifungal therapies. The general availability of genetically defined strains, immunological reagents, ease of handling, and costs all contribute to the use of mice as the primary laboratory animal species for models of this disease. Five types of murine models are studied and include primary pulmonary disease, intraperitoneal with dissemination, intravenous infection emulating systemic disease, and intracranial or intrathecal infection emulating meningeal disease. Each of these models has been used to examine various aspects of host resistance, pathogenesis, or antifungal therapy. Other rodent species, such as rat, have been used much less frequently. A rabbit model of meningeal disease, established by intracisternal infection, has proven to model human meningitis well. This model is useful in studies of host response, as well as in therapy studies. A variety of other animal species including dogs, primates, and guinea pigs have been used to study host response and vaccine efficacy. However, cost and increased needs of animal care and husbandry are limitations that influence the use of the larger animal species.

Murine peritoneal macrophages, after adherence and establishment in culture in vitro in the presence of medium containing fetal bovine serum (FBS) for 20 h, then cultured for 20 h, produced several cytokines. If, in the second 20 h period, a fungus (heat-killed Blastomyces, HK-Bd) was introduced, a more complex pattern of cytokine (particularly TNF) and chemokine production ensued. The cytokine production, assayed by antibody array and also quantitation in supernatants, was depressed (particularly TNF) by the addition of mouse serum to these cultures, with the exception of IL-6. Macrophages could be cultured in the presence or absence of serum during the initial 20 h adherence and establishment period, enabling study of the effect of serum factors. In the absence of serum, with or without fungal stimulation, cytokine and chemokine production was more restricted, largely to TNF and IL-6. The addition of mouse serum [corrected] resulted in marked depression of TNF and enhancement of IL-6. The combination of HK-Bd and mouse serum resulted in more IL-6 production than either component alone. The enhancement of IL-6 by mouse serum was concentration-dependent and maximal at 8 h. The effects of fungus or serum on macrophage production of cytokines were similar in an outbred and an inbred mouse strain. The larger repertoire of cytokine production in the macrophages that had been cultured longer (20 h+20 h) in serum may be related to maturation of cell receptors. IL-6 production in vivo in response to fungal-serum complexes could affect pathogenesis by opposing the host defense modulation by proinflammatory cytokines or by modulating the destructive effects of inflammation on host tissues.

Cryptococcus neoformans (Cn) var. grubii or Cryptococcus neoformans var. neoformans infection is usually associated with immunocompromised hosts, whereas Cryptococcusgattii more frequently causes disease in immunocompetent hosts. We examined the effects of immunodeficiency and glucocorticoid-induced immunosuppression on systemic murine infection induced by i.v. inoculation with these pathogens. SCID and immunocompetent BALB/c and C57BL/6 mice were infected with

Objectives: Cerebral scedosporiosis is a life-threatening infection that is difficult to treat. The aim of this work was to develop a murine model of cerebral infection by Scedosporium apiospermum using intracranial inoculation and to use this model to evaluate the efficacy of amphotericin B deoxycholate and liposomal amphotericin B., Methods: Mice were rendered neutropenic by intraperitoneal cyclophosphamide and intravenous (iv) 5-fluorouracil administration. Animals were infected with iv or intracranial inoculation of 1 x 10(4), 5 x 10(4) or 5 x 10(5) cfu of a clinical strain of S. apiospermum. Tissue burden reduction was determined in kidneys and brain 4 days after the infection. Efficacy of amphotericin B and liposomal amphotericin B (0.8 mg/kg/day intraperitoneally and 40 mg/kg/day iv, respectively) was evaluated in neutropenic mice infected iv or intracranially with 5 x 10(4) cfu. Survival was analysed with the log-rank test. Fungal burden values of different groups were compared using the Mann-Whitney U-test., Results: In our model, intracranial infection produced a higher fungal load in the brain and a lower fungal load in the kidney than iv inoculation. Survival of animals infected intracranially and treated with amphotericin B or liposomal amphotericin B (mean survival time = 8.3 and 9.2 days, respectively) was not different from the control group (P=0.58 and 0.85, respectively)., Conclusions: We have developed a murine model of cerebral scedosporiosis, which may be useful for studying various pathological aspects of this infection and evaluating new therapeutic approaches. Amphotericin B and liposomal amphotericin B were unable to resolve the infection.

There are no effective therapeutics for treating invasive Scedosporium prolificans infections. Doses of 15, 25, and 50 mg/kg of body weight/day for the new triazole albaconazole (ABC) were evaluated in an immunocompetent rabbit model of systemic infection with this mold. Treatments were begun 1 day after challenge and given for 10 days. ABC at any dose was more effective than amphotericin B (AMB) at 0.8 mg/kg/day at clearing S. prolificans from tissue (P < 0.007). The percentages of survival at 25 mg of ABC/kg/day were similar to those obtained with AMB. Rabbits showed 100% survival when they were treated with 50 mg of ABC per kg (P < 0.0001 versus control group), and only this dosage was able to reduce tissue burden significantly in the five organs studied, i.e., spleen, kidneys, liver, lungs, and brain.

We established a reproducible lethal disseminated infection by the opportunistic fungus Scedosporium prolificans in an immunosuppressed murine model. We compared the effectiveness of the combined administration of liposomal amphotericin B (LAMB) and granulocyte colony-stimulating factor (G-CSF) with that of either agent alone and with that of amphotericin B deoxycholate (AMB). LAMB + G-CSF and LAMB treatments improved survival significantly with respect to the untreated control. The mean survival times of these three groups were 13.2, 9.1 and 7.9 days, respectively. Culture results in terms of colony counts for samples of deep organs were lower in mice treated with the combined therapy, although differences were not significant. Combined LAMB + G-CSF therapy could be a promising approach for the treatment of disseminated infections of S. prolificans, although further studies are required to determine the most appropriate doses.