Role of the Fusarium oxysporum metallothionein Mt1 in resistance to metal toxicity and virulence.

Soil organisms exhibit high tolerance to heavy metals, probably acquired through evolutionary adaptation to contaminated environments. Essentially, metal tolerance in fungi involves several specific and non-specific mechanisms that include metal efflux, metal binding to cell walls, extracellular and intracellular sequestration and complexation with proteins. However, fungi have adopted different strategies to detoxify heavy metals, although species differ in the mechanisms used. In this complex molecular framework, metallothioneins (MTs) are becoming increasingly relevant in metal homeostasis, even though little is known about their role in metal adaptation and virulence in fungal pathogens. With the aim to decipher the function of metallothioneins in the opportunistic fungus Fusarium oxysporum, we have carried out an in silico analysis that revealed the presence of a hypothetical metallothionein (mt1) that has multiple metal responsive elements in its promoter region and conserved cysteine motifs in its coding sequence. Characterization of strain Δmt1 deficient in the mt1 gene revealed higher sensitivity of this mutant to copper, cadmium and zinc compared to the wild type strain (wt). Expression analyses revealed that Zn specifically activates mt1, but the lack of this gene did not lead to a transcriptional up-regulation of genes gapdh and prx, associated with the oxidative stress response. The lack of mt1 did not alter the pathogenic capacity of the fungus, either in tomato plant or in a murine model of systemic infection. Nevertheless, Δmt1 displayed lower resistance to macrophage killing, suggesting a connection between the absence of mt1 and impaired defence capacity against copper and reactive oxygen species.

Invasive fusariosis masquerading as extramedullary disease in rapidly progressive acute lymphoblastic leukemia.

Invasive fusariosis (IF) most commonly occurs in patients with hematologic malignancies and severe neutropenia, particularly during concomitant corticosteroid use. Breakthrough infections can occur in high-risk patients despite Aspergillus-active antifungal prophylaxis. We describe a patient with rapid acute lymphoblastic leukemia (ALL) progression who presented with multifocal skin nodules thought to be choloromatous disease. These lesions were ultimately diagnosed as IF and the patient had two simultaneously active disease processes. This case highlights the importance of pathologic diagnosis of new skin lesions in ALL patients, even during leukemia progression, and demonstrates that IF can occur despite normal neutrophil counts and Aspergillus-active prophylaxis.

[Successful treatment of disseminated fusariosis in a febrile neutropenic patient with combined antifungal therapy of voriconazol plus amphotericin B deoxycholate]. / Tratamiento exitoso de una fusariosis diseminada en un paciente neutropénico febril con terapia antifúngica combinada de voriconazol más anfotericina B deoxicolato.

We report a case of a patient with acute lymphoblastic leukemia (ALL), who developed a disseminated infection by Fusarium verticillioides during chemotherapy-induced neutropenia. He was successfully treated only after combination therapy with voriconazole plus amphotericin B deoxycolate was used, but not when these compounds were used in an isolated form.

Disseminated fusariosis with cutaneous involvement in hematologic malignancies: report of six cases with high mortality rate

Abstract: Fusariosis is due to inhalation or direct contact with conidia. Clinical presentation depends on host's immunity and can be localized, focally invasive or disseminated. Given the severity of this infection and the possibility for the dermatologist to make an early diagnosis, we report six cases of patients with hematologic malignancies, who developed febrile neutropenia an skin lesions suggestive of cutaneous fusariosis. All patients had skin cultures showing growth of Fusarium solani complex, and they received amphotericin B and voriconazole. As this infection can quickly lead to death, dermatologists play a crucial role in diagnosing this disease.

Disseminated fusariosis with cutaneous involvement in hematologic malignancies: report of six cases with high mortality rate.

Fusariosis is due to inhalation or direct contact with conidia. Clinical presentation depends on host's immunity and can be localized, focally invasive or disseminated. Given the severity of this infection and the possibility for the dermatologist to make an early diagnosis, we report six cases of patients with hematologic malignancies, who developed febrile neutropenia an skin lesions suggestive of cutaneous fusariosis. All patients had skin cultures showing growth of Fusarium solani complex, and they received amphotericin B and voriconazole. As this infection can quickly lead to death, dermatologists play a crucial role in diagnosing this disease.

Tratamiento exitoso de una fusariosis diseminada en un paciente neutropénico febril con terapia antifúngica combinada de voriconazol más anfotericina B deoxicolato / Successful treatment of disseminated fusariosis in a febrile neutropenic patient with combined antifungal therapy of voriconazol plus amphotericin B deoxycholate

Resumen Presentamos el caso clínico de un paciente con una leucemia linfoblástica aguda (LLA) que desarrolló una fusariosis diseminada por Fusarium verticillioides durante un episodio prolongado de neutropenia febril post quimioterapia. Fue exitosamente tratado cuando se usó terapia combinada de voriconazol más anfotericina B deoxicolato.

We report a case of a patient with acute lymphoblastic leukemia (ALL), who developed a disseminated infection by Fusarium verticillioides during chemotherapy-induced neutropenia. He was successfully treated only after combination therapy with voriconazole plus amphotericin B deoxycolate was used, but not when these compounds were used in an isolated form.

Infections Caused by Fusarium Species in Pediatric Cancer Patients and Review of Published Literature.

Fusarium species have emerged as responsible for a broad spectrum of infections, including superficial, locally invasive and disseminated ones, especially in the hospital environment. Since there are few reports of invasive and disseminated fusariosis in children, the aim of this study was to report four cases of nosocomial infection caused by this microorganism in children with cancer hospitalized in a public children's hospital located in Brazil. Two of these patients were female and two were male. All patients presented febrile neutropenia, while three patients had acute lymphocytic leukemia and one patient had Wilms' tumor as underlying disease. In two cases, fungi were isolated from blood and identified as Fusarium oxysporum species complex after phenotypic and genotypic studies, while in two other cases fungi were isolated from skin biopsies and identified as Fusarium solani species complex. One patient died 12 days after the onset of cutaneous lesions. All isolates, after susceptibility testing, presented high levels of minimum inhibitory concentration for itraconazole, voriconazole and amphotericin B. Considering the emergence of filamentous fungi as etiologic agents of nosocomial infections, health professionals should be aware of the problems these infections, especially fungal ones, may cause to debilitated patients.

Endogenous Fusarium Endophthalmitis During Treatment for Acute Myeloid Leukemia, Successfully Treated with 25-Gauge Vitrectomy and Antifungal Medications.

Endogenous fungal endophthalmitis (EFE) caused by disseminated fusariosis is a rare condition that generally has a poor outcome, even with intensive therapy. Here, we describe a case in which this type of EFE was diagnosed with vitreous sampling and was successfully treated with 25-gauge vitrectomy and antifungals, including liposomal amphotericin B and voriconazole. A 16-year-old male patient undergoing treatment for acute myeloid leukemia complained of eye pain and blurred vision in his right eye. Treatment was initiated for a vitreous opacity, possibly associated with herpetic retinitis, but the patient worsened and he was referred to us. Right-eye visual acuity was limited to light perception. We suspected endogenous endophthalmitis and performed 25-gauge vitrectomy with antibiotic perfusion of ceftazidime, vancomycin, and voriconazole. Vitreous culturing revealed the presence of Fusarium solani species complex, and enhanced computed tomography revealed disseminated fusariosis lesions in the lung, spleen, and the soft tissue of the left upper arm. The patient received antifungal treatment with liposomal amphotericin B and voriconazole, and these conditions were eliminated. Visual acuity recovered to 20/400 after additional vitrectomy for tractional retinal detachment and was maintained at this level during the 6-month follow-up period. The success of our treatment allowed the capture of optical coherence tomography images of the retina during fusarium-associated endogenous endophthalmitis and the follow-up period. Furthermore, this case showed that immediate vitrectomy for suspected EFE and intensive treatment can lead to a good clinical outcome.

Fusariosis in a Patient with Acute Myeloid Leukemia: A Case Report and Review of the Literature.

Fusarium spp. causes infections mostly in patients with prolonged neutropenia. We describe the case of a disseminated Fusarium solani infection in a patient with acute myeloid leukemia which never reached complete remission during its clinical course. The patient had profound neutropenia and developed skin nodules and pneumonia in spite of posaconazole prophylaxis. F. solani was isolated from blood and skin biopsy, being identified from its morphology and by molecular methods. By broth dilution method, the strain was resistant to azoles, including voriconazole and posaconazole, and to echinocandins. MIC to amphotericin B was 4 mg/L. The patient initially seemed to benefit from therapy with voriconazole and amphotericin B, but, neutropenia perduring, his clinical condition deteriorated with fatal outcome. All efforts should be made to determine the correct diagnosis as soon as possible in a neutropenic patient and to treat this infection in a timely way, assuming pathogen susceptibility while tests of antimicrobial susceptibility are pending. A review of the most recent literature on invasive fungal infections is reported.

Rhizopus arrhizus and Fusarium solani Concomitant Infection in an Immunocompromised Host.

Neutropenic patients are at risk of the development of hyalohyphomycosis and mucormycosis. Correct identification is essential for the initiation of the specific treatment, but concomitant mold infections are rarely reported. We report one unprecedented case of concomitant mucormycosis and fusariosis in a neutropenic patient with acute myeloid leukemia. The patient developed rhino-orbital infection by Rhizopus arrhizus and disseminated infection by Fusarium solani. The first culture from a sinus biopsy grew Rhizopus, which was consistent with the histopathology report of mucormycosis. A second sinus biopsy collected later during the patient's clinical deterioration was reported as hyalohyphomycosis, and the culture yielded F. solani. Due to the discordant reports, the second biopsy was reviewed and two hyphae types suggestive of both hyalohyphomycetes and mucormycetes were found. The dual mold infection was confirmed by PCR assays from paraffinized tissue sections. Increased awareness of the existence of dual mold infections in at-risk patients is necessary. PCR methods in tissue sections may increase the diagnosis of dual mold infections. In case of sequential biopsies showing discrepant results, mixed infections have to be suspected.

Urinary Tract Infection (UTI) Caused by Fusarium proliferatum in an Agranulocytosis Patient and a Review of Published Reports.

Infections caused by Fusarium species are increasing in frequency among immunocompromised hosts, but urinary tract infection (UTI) due to Fusarium proliferatum has not been reported in the literature so far. We describe a case of UTI caused by F. proliferatum in a 47-year-old man who was diagnosed with rectal cancer and metastasis. He underwent radical resection of rectal carcinoma and local resection of hepatic metastases. After the first adjuvant chemotherapy, the patient presented the obvious high fever, severely diarrhea and progressive decline of the white blood cell count. The direct microscopic examination of fungi in urine was positive, and the fungal cultures showed white, cotton-like colony. After the DNA sequencing, it was identified as F. proliferatum. We gave the patient itraconazole and other antibiotics to fight the infection. A month later, the temperature dropped to normal and the results of the direct microscopic examination and culture of fungi in urine turn negative. The itraconazole is effective against F. proliferatum.

A Case of Fungus Ball-Type Pansinusitis Due to Fusarium proliferatum.

Incidence of fungal sinusitis due to the genus Fusarium has increased during the last two decades. We report a case of fungus ball sinusitis with multiple sinuses involvement in an Iranian 21-year-old woman. The patient was diagnosed as having a fungus ball-type sinusitis in computed tomography scan. The sinus biopsy revealed fungal structures on histopathological and direct microscopic examinations and a Fusarium species arose in culture. Partial sequencing of the translation elongation factor 1-alpha identified the isolate as F. proliferatum. Removal of all lesions by endoscopic surgery resulted in a favorable outcome. To the best of our knowledge, this is the first case of F. proliferatum-associated fungus ball which involved multi-sinus and highlights the efficiency of molecular methods for discrimination of fungal agents involved.

Disseminated Fusarium infection in autologous stem cell transplant recipient

Disseminated infection by Fusarium is a rare, frequently lethal condition in severely immunocompromised patients, including bone marrow transplant recipients. However, autologous bone marrow transplant recipients are not expected to be at high risk to develop fusariosis. We report a rare case of lethal disseminated Fusarium infection in an autologous bone marrow transplant recipient during pre-engraftment phase.

Disseminated Fusarium infection in autologous stem cell transplant recipient.

Disseminated infection by Fusarium is a rare, frequently lethal condition in severely immunocompromised patients, including bone marrow transplant recipients. However, autologous bone marrow transplant recipients are not expected to be at high risk to develop fusariosis. We report a rare case of lethal disseminated Fusarium infection in an autologous bone marrow transplant recipient during pre-engraftment phase.

Role of activated macrophages in experimental Fusarium solani keratitis.

Macrophages under the conjunctival tissue are the first line defender cells of the corneas. Elimination of these cells would lead to aggravation of fungal keratitis. To determine how the course of fungal keratitis would be altered after the activation of these macrophages, a murine model was achieved by intrastromal instillation of latex beads before the corneas were infected with Fusarium solani. The keratitis was observed and clinically scored daily. Infected corneas were homogenized for colony counts. The levels of the IL-12, IL-4, MPO, MIF and iNOS cytokines were measured in the corneas using real-time polymerase chain reactions and enzyme-linked immunosorbent assays. CD3+, CD4+ and CD8+ lymphocytes in the corneas, submaxillary lymph nodes and peripheral blood were detected using immunohistochemistry and flow cytometry, respectively. The latex bead-treated mice exhibited aggravated keratitis. Substantially increased macrophage and polymorphonuclear leukocyte infiltration was detected in the corneas, although few colonies were observed. There was a marked increase in the IL-12, IL-4, MPO, MIF and iNOS expression in the corneas. The numbers of CD3+, CD4+ and CD8+ lymphocytes and the CD4+/CD8+ ratio were significantly enhanced in the corneas and submaxillary lymph nodes. However, the number of CD4+ lymphocytes was decreased in the peripheral blood, while the number of CD8+ lymphocytes increased. Collectively, our data demonstrate that the activation of macrophages in the cornea may cause an excessive immune response. Macrophages appear to play a critical role in regulating the immune response to corneal infections with F. solani.

Fatal breakthrough infection with Fusarium andiyazi: new multi-resistant aetiological agent cross-reacting with Aspergillus galactomannan enzyme immunoassay.

Disseminated infections caused by members of the Fusarium fujikuroi species complex (FFSC) occur regularly in immunocompromised patients. Here, we present the first human case caused by FFSC-member Fusarium andiyazi. Fever, respiratory symptoms and abnormal computerised tomography findings developed in a 65-year-old man with acute myelogenous leukaemia who was under posaconazole prophylaxis during his remission-induction chemotherapy. During the course of infection, two consecutive blood galactomannan values were found to be positive, and two blood cultures yielded strains resembling Fusarium species, according to morphological appearance. The aetiological agent proved to be F. andiyazi based on multilocus sequence typing. The sequencing of the internal transcribed spacer region did not resolve the closely related members of the FFSC, but additional data on partial sequence of transcription elongation factor 1 alpha subunit did. A detailed morphological study confirmed the identification of F. andiyazi, which had previously only been reported as a plant pathogen affecting various food crops.