Peritonitis por fusarium en paciente en diálisis peritoneal domiciliaria / Fusarium peritonitis in a patient on home peritoneal dialysis

Introducción: La peritonitis fúngica es una complicación infrecuente pero grave para un paciente en diálisis peritoneal domiciliaria. Objetivo: Describir un caso de peritonitis fúngica en un paciente en diálisis peritoneal continua ambulatoria (DPCA). Métodos: Se presenta un paciente masculino de 53 años de edad, con antecedentes de hipertensión arterial, 9 años en diálisis peritoneal continua ambulatoria, con una desnutrición proteico energética moderada. Durante su tratamiento presentó varios episodios de peritonitis bacterianas, infecciones del orificio de salida y una recolocación de catéter peritoneal con cuff extruido. Se trabajó con sus antecedentes, cuadro clínico, agente etiológico y tratamiento. El diagnóstico se estableció por la presencia de líquido peritoneal turbio, conteo celular con más de 100 leucocitos/ul y cultivo con la presencia del hongo filamentoso. Resultados: En diciembre de 2017 se le diagnostica una peritonitis por fusarium, sin leucocitosis ni anemia, sí presentaba una hipoalbuminemia, se cultiva además pared de la habitación donde el paciente se realizaba los intercambios y se encuentra hongo filamentoso. En principio se comienza tratamiento con vancomicina y ceftacidima, posteriormente se cambia la ceftazidima por amikacina y finalmente, al tener resultado de cultivo y se muestra el patógeno, se inicia tratamiento con itraconazol, lamentablemente el paciente fallece a los 20 días. Conclusiones: Con esta investigación se analizan aspectos clínicos y microbiológicos de la peritonitis por fusarium, los cuales son poco conocidos en diálisis peritoneal domiciliaria(AU)

Introduction: Fungal peritonitis is an infrequent but serious complication for a patient on home peritoneal dialysis. Objective: To describe a case of fungal peritonitis in a patient on continuous ambulatory peritoneal dialysis (CAPD). Methods: A 53-year-old male patient is reported, with a history of arterial hypertension, 9 years on continuous outpatient peritoneal dialysis, moderate protein-energy malnutrition. During his treatment, he had several episodes of bacterial peritonitis, exit-site infections, and repositioning of a peritoneal catheter with an extruded cuff. We worked with his antecedents, clinical status, etiological agent and treatment. The diagnosis was established by the presence of cloudy peritoneal fluid, cell count higher than 100 leukocytes / ul, and culture with the presence of the filamentous fungus. Results: In December 2017, he was diagnosed with fusarium peritonitis, with no leukocytosis or anemia, he did present hypoalbuminemia. A culture was performed on the wall of the room where the patient had his exchanges and filamentous fungus was found. Initially, treatment started with vancomycin and ceftazidime, followed by amikacin. Finally, after having a culture showed the pathogen, treatment with itraconazole started. Unfortunately the patient died 20 days later. Conclusions: This research analyzes clinical and microbiological aspects of fusarium peritonitis, which are poorly understood in home peritoneal dialysis(AU)

A retrospective cohort of invasive fusariosis in the era of antimould prophylaxis.

Mould-active prophylaxis is affecting the epidemiology of invasive mycoses in the form of a shift toward less common entities such as fusariosis. We analyze the characteristics of invasive fusariosis and its association to antifungal prophylaxis in a retrospective cohort (2004-2017) from a tertiary hospital in Madrid, Spain. Epidemiological, clinical, microbiological, and antifungal consumption data were retrieved. Isolates were identified to molecular level, and antifungal susceptibility was tested. Eight cases of invasive fusariosis were diagnosed. Three periods were identified according to incidence: <2008 (three cases), 2008-2013 (zero cases), >2014 (five cases). All except one case involved breakthrough fusariosis. During the earliest period, the episodes occurred while the patient was taking itraconazole (two) or fluconazole (one); more recently, while on micafungin (three) or posaconazole (one). Early cases involved acute leukemia at induction/consolidation, recent cases relapsed/refractory disease (P = .029). Main risk factor for fusariosis (62.5%) was prolonged neutropenia (median 44 days). Galactomannan and beta-D-glucan were positive in 37.5% and 100% of cases, respectively. All isolates except F. proliferatum presented high minimal inhibitory concentrations (MICs) against the azoles and lower MIC to amphotericin B. Most patients received combined therapy. Mortality at 42 days was 62.5%. Resolution of neutropenia was associated with survival (P = .048). Invasive fusariosis occurs as breakthrough infection in patients with hematologic malignancy, prolonged neutropenia, and positive fungal biomarkers. Recent cases were diagnosed in a period of predominant micafungin use in patients who had more advanced disease and protracted neutropenia and for whom mortality was extremely high. Resolution of neutropenia was a favorable prognostic factor.

Fosmanogepix (APX001) Is Effective in the Treatment of Immunocompromised Mice Infected with Invasive Pulmonary Scedosporiosis or Disseminated Fusariosis.

There are limited treatment options for immunosuppressed patients with lethal invasive fungal infections due to Fusarium and Scedosporium Manogepix (MGX; APX001A) is a novel antifungal that targets the conserved Gwt1 enzyme required for localization of glycosylphosphatidylinositol-anchored mannoproteins in fungi. We evaluated the in vitro activity of MGX and the efficacy of the prodrug fosmanogepix (APX001) in immunosuppressed murine models of hematogenously disseminated fusariosis and pulmonary scedosporiosis. The MGX minimum effective concentration (MEC) for Scedosporium isolates was 0.03 µg/ml and ranged from 0.015 to 0.03 µg/ml for Fusarium isolates. In the scedosporiosis model, treatment of mice with 78 mg/kg and 104 mg/kg of body weight fosmanogepix, along with 1-aminobenzotriazole (ABT) to enhance the serum half-life of MGX, significantly increased median survival time versus placebo from 7 days to 13 and 11 days, respectively. Furthermore, administration of 104 mg/kg fosmanogepix resulted in an ∼2-log10 reduction in lung, kidney, or brain conidial equivalents/gram tissue (CE). Similarly, in the fusariosis model, 78 mg/kg and 104 mg/kg fosmanogepix plus ABT enhanced median survival time from 7 days to 12 and 10 days, respectively. A 2- to 3-log10 reduction in kidney and brain CE was observed. In both models, reduction in tissue fungal burden was corroborated with histopathological data, with target organs showing reduced or no abscesses in fosmanogepix-treated mice. Survival and tissue clearance were comparable to a clinically relevant high dose of liposomal amphotericin B (10 to 15 mg/kg). Our data support the continued development of fosmanogepix as a first-in-class treatment for infections caused by these rare molds.

The emergence of zoonotic Fusarium oxysporum infection in captive-reared fingerlings of golden mahseer, Tor putitora (Hamilton, 1822) from the central Himalayan region of India.

Zoonotic Fusarium oxysporum infection was identified in captive-reared fingerlings of golden mahseer, Tor putitora (Hamilton, 1822) from the central Himalayan regions, India. Initially, fingerlings of T. putitora (mean length 10.8 ± 0.002 and weight 18.58 ± 0.054 g) were observed with cottony mass like growth completely covering the dorsal and caudal fins. The infected fingerlings were showing clinical signs such as sluggish, erratic movement, gasping, flared operculum and settling at one corner of the rearing tanks. The microscopic observation of 8-day old culture of cottony mass like growth showed the presence of septate macroconidia, randomly spread microconidia and chlamydospores in short-chain. From sequence analysis of ITS amplified fragment, the isolate was identified as Fusarium oxysporum, TPFCF 214 (MH464266.1) and clustered with F. oxysporum, strain NRRL 43504 (EF453107.1) and F. oxysporum, strain 20736 (JX 270150.1) isolated from the human in phylogenetic tree. An experimental infection of healthy golden mahseer fingerlings with 20 µl of F. oxysporum spore suspension (2.5 × 109 spore ml-1 ) showed the development of lesion 6-dpi at the site of injection. Experimental trial on EPC-2 cell culture recorded detachment in the monolayer, clumping and shrinking of the cell line 6-8 dpi with a spore suspension of F. oxysporum, TPFCF 214 (5.68 × 102 cell/ml). From the severity of its infection, there is a chance that F. oxysporum may emerge as pathogenically and pose a significant health risk on captive-reared golden mahseer in other Asian countries and world. As Fusarium solani and F. oxysporum are known to cause invasive fusariosis in human especially in immunocompromised patients, localized infection in immunocompetent individuals as well as osteomyelitis, arthritis, otitis, sinusitis and brain abscess, the global fish farmers, handlers and aquaculturist need to be aware of possible health hazards caused by Fusarium spp. and should adopt proper fish health management and animal husbandry practice to control the infection of Fusarium in culture environment.

[Filamentous fungal infection in burned patients: retrospective study.] / Infección por hongos filamentosos en pacientes quemados: estudio retrospectivo.

Introduction: Infections are the most frequent complications in burn patients. Filamentous fungi have an uncertain place within the statistics, since in our media data regarding their prevalence, causal agents and outcome of those who suffer them remain scarce. The aim of this study was to evaluate the prevalence of fungal infection by filamentous fungi (IHF) in patients hospitalized in burn intensive care unit (BICU), and to review clinical, epidemiological, microbiological and evolutionary characteristics of these patients and to know the frequency and distribution of the isolated fungi. Materials and methods: Retrospective and descriptive study. It includes all individuals admitted in burns intensive care unit (2012-2015), with positive culture for filamentous fungi in skin biopsies and bedsores. Results: A total of 168 patients were admitted in the BICU in a period of 3 years. 90% were major burned and 17% of them developed IHF (29/168). Aspergillus spp (24%), Fusarium sp (14%), Mucor spp (3%) and various black fungus genera (58%) were the main genera found in cultives. About 24% of the patients with IHF died and Fusarium spp was found in 50% of the cases. The cause of death was irreversible cardiogenic shock with multiorgan failure. Conclusions: Filamentous fungal infection was present in 17% of burned patients. The main isolatte fungi in samples were dematiaceous mould. Mortality among patients was 24%, with Fusarium being the fungus found in the highest number of deaths (50%).

Antecedentes: Las infecciones son las complicaciones más frecuentes en los pacientes quemados. Los hongos filamentosos ocupan un lugar incierto dentro de las estadísticas nosocomiales; existen escasos datos sobre la prevalencia de las mismas, los agentes causales y el desenlace de los que las padecen. Objetivos: El objetivo fue evaluar prevalencia de la infección por hongos filamentosos (IHF) en pacientes internados en la unidad terapia intensiva de quemados (UTIQ), revisar algunas características clínicas, epidemiológicas, microbiológicas y evolución de estos pacientes; conocer la frecuencia y distribución de las especies fúngicas aisladas. Materiales y métodos: Estudio retrospectivo y descriptivo. Se incluyeron todos los individuos que ingresaron a la terapia intensiva de pacientes quemados (2012-2015), con cultivo positivo para hongos filamentosos en biopsias de piel y escaras. Resultados: Un total de 168 de pacientes ingresaron en la unidad intensiva de quemados en un período de 3 años. El 17% desarrolló IHF (29/168) y el 90% fueron grandes quemados. Se recuperaron 29 hongos filamentosos (93% de exámenes microscópicos positivos): Aspergillus spp (24%), Fusarium spp (14%), Mucor spp (3%) y diversos géneros de hongos negros (58%). El 95% presentó entre 1 y 4 infecciones bacterianas además de la infección fúngica en piel. El 24% de los pacientes con IHF falleció. La causa de la muerte fue shock cardiogénico irreversible con falla multiorgánica. Conclusiones: La infección por hongos filamentosos se presentó en el 17% de los pacientes quemados. Los principales hongos causantes de infección fúngica fueron dematiáceos. La mortalidad entre los pacientes fue del 24%, siendo Fusarium el hongo hallado en el mayor número de muertes (50%).

Trasplante de médula ósea alogénico en un paciente con fusariosis diseminada y leucemia mieloide aguda / Allogeneic hematopoietic cell transplantation in a patient with disseminated fusariosis and acute myeloid leukemia

La infección diseminada por Fusarium se ha convertido en un problema creciente en las personas con neoplasias hematológicas malignas, principalmente en pacientes con leucemias agudas; se describen cada vez más casos en aquellos sometidos a un trasplante de médula ósea. No existe un tratamiento óptimo establecido para la fusariosis diseminada. La mortalidad global comunicada de esta infección oscila entre el 50 y el 80%. Se presenta a continuación el caso de un paciente de sexo masculino de 29 años, con diagnóstico de leucemia mieloide aguda, que presenta como complicación una fusariosis diseminada, y logra sobrellevar un trasplante alogénico de médula ósea en el Hospital Italiano de San Justo (Argentina) de forma exitosa. (AU)

Disseminated fusariosis has become an increasing problem in people with hematopoietic neoplasms, mainly in patients affected by acute leukemias, and even more in those who undergo hematopoietic cell transplantation. There is not an optimal treatment for disseminated fusariosis. The global mortality described in the literature is between 50% and 80%. We introduce a case of a 29 year old patient with diagnosis of acute myeloid leukemia complicated with disseminated fusariosis, who copes with an allogeneic hematopoietic cell transplantation with a successful outcome in the "Hospital Italiano de San Justo" (Argentina). (AU)

Invasive fungal sinusitis in the pediatric population: Systematic review with quantitative synthesis of the literature.

BACKGROUND: Invasive fungal sinusitis (IFS) represents an often fatal condition within the pediatric population. In an effort to characterize demographics, treatment modalities, and prognostic factors, we performed a systematic review. METHODS: We systematically reviewed EMBASE, Medline, TRIPdatabase, SCOPUS and the Cochrane database for invasive fungal nasal and sinus infections limited to individuals <18 years of age. Case series including 3 or more patients were included. Demographics, treatment and outcomes were analyzed using R Gui statistical software. RESULTS: Twelve studies met inclusion criteria (103 patients). There was male preponderance of 48.5% with median age of 11 years old. Majority of patients had underlying leukemia (44.6%). Aspergillus was the predominant organism (47%). Isolated nasal findings occurred in 14% of patients and nasal findings occurred in 49% overall. Absolute neutrophil count (ANC) of immunocompromised patients was below 600 in most patients (99%). Average and median length of neutropenia was 2 weeks. All patients were prescribed amphoterocin with 50% as single medicinal therapy. Surgery occurred in 82.8% of cases. The mortality rate was 46%. Univariate analysis identified presenting with facial pain as a negative predictor of overall mortality (OR 0.296, 95% CI: 0.104-0.843, p < 0.05). CONCLUSION: Mortality remains high in pediatric patients with IFS. An ANC of <600 occurred in the majority of immunocompromised patients at a duration of 2 weeks. Presenting with facial pain was a negative predictor of mortality. Many studies label this condition as invasive fungal sinusitis; however, approximately one seventh presented with only nasal findings and half overall had nasal involvement.

Risk factors and impact of non-Aspergillus mold infections following allogeneic HCT: a CIBMTR infection and immune reconstitution analysis.

Risk factors for non-Aspergillus mold infection (NAMI) and the impact on transplant outcome are poorly assessed in the current era of antifungal agents. Outcomes of 124 patients receiving allogeneic hematopoietic cell transplantation (HCT) diagnosed with either mucormycosis (n=72) or fusariosis (n=52) between days 0 and 365 after HCT are described and compared with a control cohort (n=11 856). Patients with NAMI had more advanced disease (mucormycois: 25%, fusariosis: 23% and controls: 18%; P=0.004) and were more likely to have a Karnofsky performance status (KPS) <90% at HCT (mucormycosis: 42%, fusariosis: 38% and controls: 28%; P=0.048). The 1-year survival after HCT was 22% (15-29%) for cases and was significantly inferior compared with controls (65% (64-65%); P<0.001). Survival from infection was similarly dismal regardless of mucormycosis: 15% (8-25%) and fusariosis: 21% (11-33%). In multivariable analysis, NAMI was associated with a sixfold higher risk of death (P<0.0001) regardless of the site or timing of infection. Risk factors for mucormycosis include preceding acute GvHD, prior Aspergillus infection and older age. For fusariosis, increased risks including receipt of cord blood, prior CMV infection and transplant before May 2002. In conclusion, NAMI occurs infrequently, is associated with high mortality and appears with similar frequency in the current antifungal era.

Fatal Cases of Bloodstream Infection by Fusarium solani and Review of Published Literature.

Fusarium species are ubiquitously present in environment and are well known as human pathogens with high mortality rate in immunocompromised patients. We report here two cases where immunocompromised patients developed fatal bloodstream infections by this organism. Isolates were further identified by ITS1 region sequencing which confirmed them as Fusarium solani. Antifungal susceptibility testing was done following CLSI M38-A2 guidelines to amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, caspofungin, and micafungin. Both patients had a fatal outcome and expired of septic shock. Therefore, identification up to species level is of utmost importance as that helps in directing the management of the patient thereby leading to a favourable outcome.

Invasive Fusariosis: A Single Pediatric Center 15-Year Experience.

Invasive fungal infection (IFI) is an important cause of mortality in immunocompromised children, particularly after hematopoietic stem cell transplantation. We describe 5 cases of Fusarium IFI in immunocompromised children seen at our institution over a 15-year period. A summary of all published pediatric cases of invasive Fusarium infection is presented. A focus on antifungal management challenges in these patients will be discussed.

Fatal disseminated infection with Fusarium petroliphilum.

Members of the Fusarium solani species complex (FSSC) are causing the majority of the fusariosis in humans. Disseminated fusariosis has a high mortality and is predominantly observed in patients with leukemia. Here, we present the case of a fatal infection by a Fusarium strain with a degenerated phenotype, in a patient with acute lymphatic leukemia. Multiple nasal and skin biopsies as well as blood cultures yielded fungal growth, while in direct and histopathological examination of biopsy material septate hyphae were visible. Initial colonies were white with slimy masses with microconidia reminiscent of Fusarium/Acremonium, but with conidiospore production directly on the hyphae. Multi-locus sequence typing discerned a pionnotal-morphologically degenerated-colony of the recently recognized F. petroliphilum as etiological agent. The culture returned to a typical F. solani species complex morphology only after several weeks of growth in culture. Antifungal susceptibility tests indicate amphotericin B as best drug for this FSSC member rather than any of the azoles or echinocandins.

Treatment and outcomes of invasive fusariosis: review of 65 cases from the PATH Alliance(®) registry.

Invasive Fusarium infections occur in immunosuppressed patients, especially those with haematological malignancies. We conducted a descriptive analysis of data from patients with invasive fusariosis identified in the Prospective Antifungal Therapy Alliance registry, which collected data on invasive fungal infections in the United States and Canada from 2004 to 2008. In this series of 65 patients with proven (83.1%) and probable (16.9%) invasive fusariosis, the most common underlying condition was haematological malignancy, in which neutropenia and corticosteroid usage frequently occurred. Seven patients with invasive Fusarium infections had cross-reactive galactomannan assay results. The survival rate for all patients at 90 days was 44%, which was an improvement compared with historical data. Disseminated disease occurred frequently (35.4%), and patients with and without disseminated disease had survival rates of 33% and 50%, respectively. Posaconazole and voriconazole were the most frequently employed therapies and may be linked to the improved survival rate observed in this patient series. In summary, patients with invasive Fusarium infections continue to have high fatality rates, especially those with disseminated disease. Fusarium infections should be strongly considered in the absence of Aspergillus isolation in patients at high risk of mould infections with positive galactomannan assay test results.

European Confederation of Medical Mycology (ECMM) epidemiological survey on invasive infections due to Fusarium species in Europe.

In order to better understand the epidemiology of fusariosis in Europe, a survey collecting information on the clinical characteristics of the patients infected by Fusarium as well as on the infecting isolates was launched. A total of 76 cases of invasive fusariosis occurring from January 2007 to June 2012 were collected and Fusarium isolates were identified by sequencing the translation elongation factor 1α (TEF) gene. Also, antifungal susceptibility was tested by broth microdilution according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Etest. Disseminated disease was considered proven in 46 cases and probable in 17 cases. Localised infection was seen in 13 cases. Gibberella fujikuroi species complex (SC), including Fusarium verticillioides and F. proliferatum, and F. solani SC were the most frequent aetiology of disseminated and localised infections, respectively. The crude mortality rate was 46 %, the highest associated with F. solani SC (67 %) and F. proliferatum (62.5 %). A wide range of antifungal susceptibilities was observed. Amphotericin B was the most potent antifungal in vitro, and itraconazole the least effective. The azoles exhibited lower minimum inhibitory concentrations (MICs) against F. verticillioides strains, with posaconazole having a slightly better performance, while F. solani SC isolates were resistant to all three azoles tested. The essential agreement between the Etest and the EUCAST method was 100 % for itraconazole and voriconazole, and 96 % for amphotericin B and posaconazole. In conclusion, we confirm that fusariosis is a rare but severe event in Europe, that G. fujikuroi SC is the predominant cause of deep infections and that different species have different antifungal in vitro susceptibility patterns.

Murine model for Fusarium oxysporum invasive fusariosis reveals organ-specific structures for dissemination and long-term persistence.

The soil-borne plant pathogen Fusarium oxysporum causes life-threatening invasive fusariosis in immunocompromised individuals. The mechanism of infection in mammalian hosts is largely unknown. In the present study we show that the symptoms of disseminated fusariosis caused by F. oxysporum in immunosuppressed mice are remarkably similar to those reported in humans. Distinct fungal structures were observed inside the host, depending on the infected organ. Invasive hyphae developed in the heart and kidney, causing massive colonization of the organs. By contrast, chlamydospore-like survival structures were found in lung, spleen and liver. Systemically infected mice also developed skin and eye infections, as well as thrombosis and necrosis in the tail. We further show that F. oxysporum can disseminate and persist in the organs of immunocompetent animals, and that these latent infections can lead to lethal systemic fusariosis if the host is later subjected to immunosuppressive treatment.

Improvement in the outcome of invasive fusariosis in the last decade.

Invasive fusariosis (IF) has been associated with a poor prognosis. Although recent series have reported improved outcomes, the definition of optimal treatments remains controversial. The objective of this study was to evaluate changes in the outcome of IF. We retrospectively analysed 233 cases of IF from 11 countries, comparing demographics, clinical findings, treatment and outcome in two periods: 1985-2000 (period 1) and 2001-2011 (period 2). Most patients (92%) had haematological disease. Primary treatment with deoxycholate amphotericin B was more frequent in period 1 (63% vs. 30%, p <0.001), whereas voriconazole (32% vs. 2%, p <0.001) and combination therapies (18% vs. 1%, p <0.001) were more frequent in period 2. The 90-day probabilities of survival in periods 1 and 2 were 22% and 43%, respectively (p <0.001). In period 2, the 90-day probabilities of survival were 60% with voriconazole, 53% with a lipid formulation of amphotericin B, and 28% with deoxycholate amphotericin B (p 0.04). Variables associated with poor prognosis (death 90 days after the diagnosis of fusariosis) by multivariable analysis were: receipt of corticosteroids (hazard ratio (HR) 2.11, 95% CI 1.18-3.76, p 0.01), neutropenia at end of treatment (HR 2.70, 95% CI 1.57-4.65, p <0.001), and receipt of deoxycholate amphotericin B (HR 1.83, 95% CI 1.06-3.16, p 0.03). Treatment practices have changed over the last decade, with an increased use of voriconazole and combination therapies. There has been a 21% increase in survival rate in the last decade.

Increased incidence of invasive fusariosis with cutaneous portal of entry, Brazil.

Invasive fusariosis (IF) is an infection with Fusarium spp. fungi that primarily affects patients with hematologic malignancies and hematopoietic cell transplant recipients. A cutaneous portal of entry is occasionally reported. We reviewed all cases of IF in Brazil during 2000-2010, divided into 2 periods: 2000-2005 (period 1) and 2006-2010 (period 2). We calculated incidence rates of IF and of superficial infections with Fusarium spp. fungi identified in patients at a dermatology outpatient unit. IF incidence for periods 1 and 2 was 0.86 cases versus 10.23 cases per 1,000 admissions (p<0.001), respectively; superficial fusarial infection incidence was 7.23 versus 16.26 positive cultures per 1,000 superficial cultures (p<0.001), respectively. Of 21 cases of IF, 14 showed a primary cutaneous portal of entry. Further studies are needed to identify reservoirs of these fungi in the community and to implement preventive measures for patients at risk.

Fusarium pathogenesis investigated using Galleria mellonella as a heterologous host.

Members of the fungal genus Fusarium are capable of manifesting in a multitude of clinical infections, most commonly in immunocompromised patients. In order to better understand the interaction between the fungus and host, we have developed the larvae of the greater wax moth, Galleria mellonella, as a heterologous host for fusaria. When conidia are injected into the haemocoel of this Lepidopteran system, both clinical and environmental isolates of the fungus are able to kill the larvae at 37 °C, although killing occurs more rapidly when incubated at 30 °C. This killing was dependent on several other factors besides temperature, including the Fusarium strain, the number of conidia injected, and the conidia morphology, where macroconidia are more virulent than their microconidia counterpart. There was a correlation in the killing rate of Fusarium spp. when evaluated in G. mellonella and a murine model. In vivo studies indicated G. mellonella haemocytes were capable of initially phagocytosing both conidial morphologies. The G. mellonella system was also used to evaluate antifungal agents, and amphotericin B was able to confer a significant increase in survival to Fusarium-infected larvae. The G. mellonella-Fusarium pathogenicity system revealed that virulence of Fusarium spp. is similar, regardless of the origin of the isolate, and that mammalian endothermy is a major deterrent for Fusarium infection and therefore provides a suitable alternative to mammalian models to investigate the interaction between the host and this increasingly important fungal pathogen.

Galleria mellonella as model host for the trans-kingdom pathogen Fusarium oxysporum.

Fusarium oxysporum, the causal agent of vascular wilt disease, affects a wide range of plant species and can produce disseminated infections in humans. F. oxysporum f. sp. lycopersici isolate FGSC 9935 causes disease both on tomato plants and immunodepressed mice, making it an ideal model for the comparative analysis of fungal virulence on plant and animal hosts. Here we tested the ability of FGSC 9935 to cause disease in the greater wax moth Galleria mellonella, an invertebrate model host that is widely used for the study of microbial human pathogens. Injection of living but not of heat-killed microconidia into the hemocoel of G. mellonella larvae resulted in dose-dependent killing both at 30°C and at 37°C. Fluorescence microscopy of larvae inoculated with a F. oxysporum transformant expressing GFP revealed hyphal proliferation within the hemocoel, interaction with G. mellonella hemocytes, and colonization of the killed insects by the fungus. Fungal gene knockout mutants previously tested in the tomato and immunodepressed mouse systems displayed a good correlation in virulence between the Galleria and the mouse model. Thus, Galleria represents a useful non-vertebrate infection model for studying virulence mechanisms of F. oxysporum on animal hosts.