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

Invasive fusariosis

Invasive fusariosis is a serious invasive fungal disease, affecting immunocompetent and, more frequently, immunocompromised patients. Localized disease is the typical clinical form in immunocompetent patients. Immunocompromised hosts at elevated risk of developing invasive fusariosis are patients with acute leukemia receiving chemotherapeutic regimens for remission induction, and those undergoing allogeneic hematopoietic cell transplant. In this setting, the infection is usually disseminated with positive blood cultures, multiple painful metastatic skin lesions, and lung involvement. Currently available antifungal agents have poor in vitro activity against Fusarium species, but a clear-cut correlation between in vitro activity and clinical effectiveness does not exist. The outcome of invasive fusariosis is largely dependent on the resolution of immunosuppression, especially neutrophil recovery in neutropenic patients.

Susceptibility patterns of amphotericin B, itraconazole, posaconazole, voriconazole and caspofungin for isolates causing invasive mould infections from the SENTRY Antifungal Surveillance Program (2018-2021) and application of single-site epidemiological cutoff values to evaluate amphotericin B activity

We evaluated the activity of amphotericin B, itraconazole, posaconazole, voriconazole and caspofungin against 1468 invasive moulds collected worldwide from 2018 to 2021. Most (>92%) of the Aspergillus spp. isolates were wildtype (WT) to amphotericin B, caspofungin and the azoles. Azole-non-wildtype A. fumigatus rates were higher in Europe (9.5%) and North America (9.1%) than Latin America (0.0%; only 12 isolates) and the Asia-Pacific region (5.3%). Amphotericin B and caspofungin were active against azole-non-wildtype A. fumigatus isolates. Posaconazole and amphotericin B were the most active agents against the Mucorales. Among the less common moulds, several expressed a pan-azole-resistant phenotype; many of these species also showed elevated MIC values (MIC, >2 mg/L) for amphotericin B and caspofungin. Although most isolates of Aspergillus spp. remain WT to the azoles, azole resistance is increasing in both North America and Europe. Amphotericin B and caspofungin exhibit potentially useful activity against azole-resistant A. fumigatus.

Fusariosis in cancer patients: 13 case series report and literature review

The fusariosis is an opportunistic mycosis caused by Fusarium spp. Its clinical presentation depends on the immunological status of the host, especially in patients with hematooncological diseases, whose manifestations vary from localized to invasive fungal infections. Skin or blood culture helps to guide combined antifungal treatment with amphotericin B and voriconazole. Here, we present 13 cases in a period of eleven years of patients with cancer who developed disseminated fusariosis and their outcomes, together with a review of the related literature. In this series of cases, mortality was 61.5 % (8/13), despite the use of the antifungal. Out of the 13 cases, 11 had hematological neoplasia and 2 solid neoplasia. The most determinant risk factor was profound neutropenia. Skin involvement and positive blood cultures in most cases allowed combined treatment prescription. Persistent febrile neutropenia associated with skin lesions, onychomycosis, nodules, or lung masses lead to suspicion of Fusarium spp. fungal invasive infection. The aim of this series of cases is to remind healthcare professionals that oncological patients with deep and persistent febrile neutropenia can develop fusariosis.

Non-Aspergillus Hyaline Molds: A Host-Based Perspective of Emerging Pathogenic Fungi Causing Sinopulmonary Diseases

The incidence of invasive sino-pulmonary diseases due to non-Aspergillus hyaline molds is increasing due to an enlarging and evolving population of immunosuppressed hosts as well as improvements in the capabilities of molecular-based diagnostics. Herein, we review the following opportunistic pathogens known to cause sinopulmonary disease, the most common manifestation of hyalohyphomycosis: Fusarium spp., Scedosporium spp., Lomentospora prolificans, Scopulariopsis spp., Trichoderma spp., Acremonium spp., Paecilomyces variotii, Purpureocillium lilacinum, Rasamsonia argillacea species complex, Arthrographis kalrae, and Penicillium species. To facilitate an understanding of the epidemiology and clinical features of sino-pulmonary hyalohyphomycoses in the context of host immune impairment, we utilized a host-based approach encompassing the following underlying conditions: neutropenia, hematologic malignancy, hematopoietic and solid organ transplantation, chronic granulomatous disease, acquired immunodeficiency syndrome, cystic fibrosis, and healthy individuals who sustain burns, trauma, or iatrogenic exposures. We further summarize the pre-clinical and clinical data informing antifungal management for each pathogen and consider the role of adjunctive surgery and/or immunomodulatory treatments to optimize patient outcome.

Non-Aspergillus mould lung infections

Non-Aspergillus filamentous fungi causing invasive mould infections have increased over the last years due to the widespread use of anti-Aspergillus prophylaxis and increased complexity and survival of immunosuppressed patients. In the few studies that have reported on invasive mould infection epidemiology, Mucorales are the most frequently isolated group, followed by either Fusarium spp. or Scedosporium spp. The overall incidence is low, but related mortality is exceedingly high. Patients with haematological malignancies and haematopoietic stem cell transplant recipients comprise the classical groups at risk of infection for non-Aspergillus moulds due to profound immunosuppression and the vast use of anti-Aspergillus prophylaxis. Solid organ transplant recipients also face a high risk, especially those receiving lung transplants, due to direct exposure of the graft to mould spores with altered mechanical and immunological elimination, and intense, associated immunosuppression. Diagnosing non-Aspergillus moulds is challenging due to unspecific symptoms and radiological findings, lack of specific biomarkers, and low sensitivity of cultures. However, the advent of molecular techniques may prove helpful. Mucormycosis, fusariosis and scedosporiosis hold some differences regarding clinical paradigmatic presentations and preferred antifungal therapy. Surgery might be an option, especially in mucormycosis. Finally, various promising strategies to restore or enhance the host immune response are under current evaluation.

A Practical Workflow for the Identification of Aspergillus, Fusarium, Mucorales by MALDI-TOF MS: Database, Medium, and Incubation Optimization

There is an increasing body of literature on the utility of MALDI-TOF MS in the identification of filamentous fungi. However, the process still lacks standardization. In this study, we attempted to establish a practical workflow for the identification of three clinically important molds: Aspergillus, Fusarium, and Mucorales using MALDI-TOF MS. We evaluated the performance of Bruker Filamentous Fungi database v3.0 for the identification of these fungi, highlighting when there would be a benefit of using an additional database, the MSI-2 for further identification. We also examined two other variables, namely, medium effect and incubation time on the accuracy of fungal identification. The Bruker database achieved correct species level identification in 85.7% of Aspergillus and 90% of Mucorales, and correct species-complex level in 94.4% of Fusarium. Analysis of spectra using the MSI-2 database would also offer additional value for species identification of Aspergillus species, especially when suspecting species with known identification limits within the Bruker database. This issue would only be of importance in selected cases where species-level identification would impact therapeutic options. Id-Fungi plates (IDFP) had almost equivalent performance to Sabouraud dextrose agar (SDA) for species-level identification of isolates and enabled an easier harvest of the isolates with occasional faster identification. Our study showed accurate identification at 24 h for Fusarium and Mucorales species, but not for Aspergillus species, which generally required 48 h.

Fusarium proliferatum-induced chronic lip ulcer: successful treatment with itraconazole: a case report

Background

Fusarium species are saprophytic fungi with a worldwide distribution. These fungi cause various infections among immunocompromised patients; however, they can also involve immunocompetent individuals.

Case presentation

We report a case of a 41-year-old Iranian woman who presented with ulcerative lesions on her lips 10 months ago. She had a long history of anxiety but had no history of classical risk factors such as trauma, cosmetic lip tattoo, burning in her lips, smoking or use of alcohol and opium. A skin biopsy from the lower lip was performed and sent for microbiological examinations. Hyaline septate hyphae were seen on direct microscopy with potassium hydroxide. The clinical specimen was subcultured on sabouraud dextrose agar with chloramphenicol and prepared for antifungal susceptibility testing and molecular identification. Considering the minimum inhibitory concentrations (MIC) for antifungals, itraconazole (100 mg orally twice a day) was started for her, and after 2 months, the lesions were treated. She followed up for 3 months, and no signs of disease recurrence were observed.

Conclusions

Selecting an appropriate treatment strategy according to the laboratory assessments is essential in clinical practice and the management of rare infections to prevent related mortality and morbidity of opportunistic fungal infections.

Filamentous Fungal Keratitis in Greece: A 16-Year Nationwide Multicenter Survey

In a multicenter, prospective study of filamentous fungal keratitis in Greece, predisposing factors, etiology, treatment practices, and outcome, were determined. Corneal scrapings were collected from patients with clinical suspicion of fungal keratitis, and demographic and clinical data were recorded. Fungal identification was based on morphology, molecular methods, and matrix assisted laser desorption ionization time-of-flight mass-spectrometry. A total of 35 cases were identified in a 16-year study period. Female to male ratio was 1:1.7 and median age 48 years. Corneal injury by plant material, and soft contact lens use were the main risk factors (42.8% and 31.4%, respectively). Trauma was the leading risk factor for men (68.1%), contact lens use (61.5%) for women. Fusarium species were isolated more frequently (n = 21, 61.8%). F. solani was mostly associated with trauma, F. verticillioides and F. proliferatum with soft contact lens use. Other fungi were: Purpureocillium lilacinum (14.7%), Alternaria (11.8%), Aspergillus (8.8%), and Phoma foliaceiphila, Beauveria bassiana and Curvularia spicifera, one case each. Amphotericin B and voriconazole MIC₅₀s against Fusarium were 2 mg/L and 4 mg/L respectively. Antifungal therapy consisted mainly of voriconazole locally or both locally and systemically, alone or in combination with liposomal AmB. Cure/improvement rate with antifungal therapy alone was 52%, keratoplasty was required in 40% of cases, and enucleation in 8%. In conclusion, filamentous fungal keratitis in Greece is rare, but with considerable morbidity. A large proportion of cases resulted in keratoplasty despite appropriate antifungal treatment.Kindly confirm the given name and family name are correctly identified for all authros.ConfirmedJournal instruction requires a city and country for affiliations; however, these are missing in affiliations 1, 3, 4, 5, 6, 13. Please verify if the provided city and country are correct and amend if necessary.All provided cities and countries are correct.

Fusarium solani Necrotizing Fasciitis Complicating Treatment for Acute Lymphoblastic Leukemia: A Case Report

Fungal infections due to Fusarium species are serious albeit rare and mostly occur in severely immunocompromised patients. The prognosis of such infections, especially of disseminated manifestations, is poor as a result of multi-antifungal resistance, particularly to azoles. We report a case of a rapidly progressive necrotizing fasciitis of the foot secondary to Fusarium solani in a young female patient with acute lymphoblastic leukemia on consolidation therapy. Surgical debridement was undertaken and liposomal amphotericin was given as definitive therapy for a total of six weeks followed by secondary prophylaxis that resulted in remarked clinical and radiological improvement. High clinical suspicion, prompt surgical intervention, rapid diagnosis, and timely initiation of appropriate antifungal therapy are crucial for a favorable outcome in this relatively uncommon life-threatening infection.

Rapid Identification of Four Fusarium spp. Complex by High-Resolution Melting Curve Analysis and their Antifungal Susceptibility Profiles

Fusarium species are globally distributed filamentous ascomycete fungi that are frequently reported as plant pathogens and opportunistic human pathogens, leading to yield loss of crops, mycotoxin contamination of food and feed products as well as damage to human and livestock. Human infections of Fusarium spp. are difficult to treat due to broad antifungal resistance by members of this genus. Their role as disease-causing agents in crops and humans suggests a need for antifungal resistance profiles as well as a simple, rapid, and cost effective identification method. Fusarium strains were isolated from food and clinical samples. High-resolution melting curve (HRM) analysis was performed using specific primers targeting internal transcribed spacer (ITS) region, followed with evaluation of specificity and sensitivity. The antifungal susceptibility of four Fusarium species was studied using the Sensititre YeastOne method. HRM analysis revealed reproducible, unimodal melting profiles specific to each of the four Fusarium strains, while no amplification of the negative controls. The minimum detection limits were 100-120 copies based on a 2 µl volume of template. Clear susceptibility differences were observed against antifungal agents by different Fusarium isolates, with amphotericin B and voriconazole displayed strongest antifungal effects to all the tested strains. We developed a simple, rapid, and low-cost qPCR-HRM method for identification of four Fusarium spp. (F. oxysporum, F. lateritium, F. fujikuroi, and F. solani). The antifungal susceptibility profiles supplied antifungal information of foodborne and clinical Fusarium spp. and provided guidance for clinical treatment of human infections.

CYP51 Mutations in the Fusarium solani Species Complex: First Clue to Understand the Low Susceptibility to Azoles of the Genus Fusarium

Members of Fusarium solani species complex (FSSC) are cosmopolitan filamentous fungi responsible for invasive fungal infections in immunocompromised patients. Despite the treatment recommendations, many strains show reduced sensitivity to voriconazole. The objective of this work was to investigate the potential relationship between azole susceptibility and mutations in CYP51 protein sequences. Minimal inhibitory concentrations (MICs) for azole antifungals have been determined using the CLSI (Clinical and Laboratory Standards Institute) microdilution method on a panel of clinical and environmental strains. CYP51A, CYP51B and CYP51C genes for each strain have been sequenced using the Sanger method. Amino acid substitutions described in multiple azole-resistant Aspergillus fumigatus (mtrAf) strains have been sought and compared with other Fusarium complexes’ strains. Our results show that FSSC exhibit point mutations similar to those described in mtrAf. Protein sequence alignments of CYP51A, CYP51B and CYP51C have highlighted different profiles based on sequence similarity. A link between voriconazole MICs and protein sequences was observed, suggesting that these mutations could be an explanation for the intrinsic azole resistance in the genus Fusarium. Thus, this innovative approach provided clues to understand low azole susceptibility in FSSC and may contribute to improving the treatment of FSSC infection.

Factors associated with breakthrough fungemia caused by Candida, Trichosporon, or Fusarium species when the breakthrough fungemia developed in patients with hematological disorders

Limited data are available on breakthrough fungemia, defined as fungemia that develops on administration of antifungal agents, in patients with hematological disorders. We reviewed the medical and microbiological records of adult patients with hematological diseases who had breakthrough fungemia between January 2008 and July 2019 at Toranomon Hospital and Toranomon Hospital Kajigaya in Japan. A total of 121 cases of breakthrough fungemia were identified. Of the 121 cases, 83, 11, 5, and 22 were receiving micafungin, voriconazole, itraconazole, and liposomal amphotericin B, respectively, when the breakthrough occurred. Of the 121 causative breakthrough fungal strains, 96 were Candida species, and the rest were 13 cases of Trichosporon species, 7 of Fusarium species, 2 of Rhodotorula mucilaginosa, and 1 each of Cryptococcus neoformans, Exophiala dermatitidis, and Magnusiomyces capitatus. The crude 14-day mortality rate of breakthrough fungemia was 36%. Significant independent factors associated with the crude 14-day mortality were age ≥60 years (P=0.011), chronic renal failure (P=0.0087), septic shock (P<0.0001), steroid administration (P=0.0085), and liposomal amphotericin B breakthrough fungemia (P=0.0011). An absolute neutrophil count >500/μL was significantly more common in candidemia in the multivariate analysis(P＝0.0065), neutropenia and non-allogeneic hematopoietic stem cell transplant recipients were significantly more common in Trichosporon fungemia (P=0.036 and P=0.033, respectively), and voriconazole breakthrough fungemia and neutropenia were significantly more common in Fusarium fungemia (P=0.016 and P=0.016, respectively). The epidemiological and clinical characteristics of breakthrough fungemia of patients with hematological disorders were demonstrated. Some useful factors to predict candidemia, Trichosporon fungemia, and Fusarium fungemia were identified.

Consensus guidelines for the diagnosis and management of invasive fungal disease due to moulds other than Aspergillus in the haematology/oncology setting, 2021

Invasive fungal disease (IFD) due to moulds other than Aspergillus is a significant cause of mortality in patients with malignancies or post haemopoietic stem cell transplantation. The current guidelines focus on the diagnosis and management of the common non-Aspergillus moulds (NAM), such as Mucorales, Scedosporium species (spp.), Lomentospora prolificans and Fusarium spp. Rare but emerging NAM including Paecilomyces variotii, Purpureocillium lilacinum and Scopulariopsis spp. are also reviewed. Culture and histological examination of tissue biopsy specimens remain the mainstay of diagnosis, but molecular methods are increasingly being used. As NAM frequently disseminate, blood cultures and skin examination with biopsy of any suspicious lesions are critically important. Treatment requires a multidisciplinary approach with surgical debridement as a central component. Other management strategies include control of the underlying disease/predisposing factors, augmentation of the host response and the reduction of immunosuppression. Carefully selected antifungal therapy, guided by susceptibility testing, is critical to cure. We also outline novel antifungal agents still in clinical trial which offer substantial potential for improved outcomes in the future. Paediatric recommendations follow those of adults. Ongoing epidemiological research, improvement in diagnostics and the development of new antifungal agents will continue to improve the poor outcomes that have been traditionally associated with IFD due to NAM.

Contribution of NADPH-cytochrome P450 Reductase to Azole Resistance in Fusarium oxysporum

Fusarium species exhibit significant intrinsic resistance to most antifungal agents and fungicides, resulting in high mortality rates among immunocompromised patients. Consequently, a thorough characterization of the antifungal resistance mechanism is required for effective treatments and for preventing fungal infections and reducing antifungal resistance. In this study, an isolate of Fusarium oxysporum (wild-type) with broadly resistant to commonly antifungal agents was used to generate 1,450 T-DNA random insertion mutants via Agrobacterium tumefaciens-mediated transformation. Antifungal susceptibility test results revealed one mutant with increased sensitivity to azoles. Compared with the resistant wild-type, the mutant exhibited low MICs to KTZ, ITC, VRC, POS, and PCZ (0.125, 1, 0.06, 0.5, and 0.125μg/ml, respectively). The T-DNA insertion site of this mutant was characterized as involving two adjacent genes, one encoding a hypothetical protein with unknown function and the other encoding the NADPH-cytochrome P450 reductase, referred as CPR1. To confirm the involvement of these genes in the altered azole susceptibility, the independent deletion mutants were generated and the Cpr1 deletion mutant displayed the same phenotypes as the T-DNA random mutant. The deletion of Cpr1 significantly decreased ergosterol levels. Additionally, the expression of the downstream Cyp51 gene was affected, which likely contributed to the observed increased susceptibility to azoles. These findings verified the association between Cpr1 and azole susceptibility in F. oxysporum. Furthermore, this gene may be targeted to improve antifungal treatments.

Invasive Fusariosis in Patients with Hematologic Diseases

Fusarium species are filamentous fungi widely encountered in nature, and may cause invasive disease in patients with hematologic conditions. Patients at higher risk are those with acute leukemia receiving induction remission chemotherapy or allogeneic hematopoietic cell transplant recipients. In these hosts, invasive fusariosis presents typically with disseminated disease, fever, metastatic skin lesions, pneumonia, and positive blood cultures. The prognosis is poor and the outcome is largely dependent on the immune status of the host, with virtually a 100% death rate in persistently neutropenic patients, despite monotherapy or combination antifungal therapy. In this paper, we will review the epidemiology, clinical manifestations, diagnosis, and management of invasive fusariosis affecting patients with hematologic diseases.

Biosynthesis, regulation, and biological significance of fumonisins in fungi: current status and prospects

Fumonisins are one of the most important mycotoxin classes due to their widespread occurrence and potential health threat to humans and animals. Currently, most of the research focuses on the control of fumonisin contamination in the food supply chain. In recent years, significant progress in biochemistry, enzymology, and genetic regulation of fumonisin biosynthesis has been achieved using molecular technology. Furthermore, new insights into the roles of fumonisins in the interaction between fungi and plant hosts have been reported. This review provides an overview of the current understanding of the biosynthesis and regulation of fumonisins. The ecological significance of fumonisins to Fusarium species that produce the toxins is discussed, and the complex regulatory networks of fumonisin synthesis is proposed.

Fusarium musae from Diseased Bananas and Human Patients: Susceptibility to Fungicides Used in Clinical and Agricultural Settings

Fusarium musae belongs to the Fusarium fujikuroi species complex. It causes crown rot disease in banana but also keratitis and skin infections as well as systemic infections in immunocompromised patients. Antifungal treatments in clinical and agricultural settings rely mostly on molecules belonging to the azole class. Given the potential risk of pathogen spread from food to clinical settings, the goal of the work was to define the level of susceptibility to different azoles of a worldwide population of F. musae. Eight fungicides used in agriculture and five antifungals used in clinical settings (4 azoles and amphotericin B) were tested using the CLSI (Clinical and Laboratory Standards Institute) protocol methodology on 19 F. musae strains collected from both infected patients and bananas. The level of susceptibility to the different active molecules was not dependent on the source of isolation with the exception of fenbuconazole and difenoconazole which had a higher efficiency on banana-isolated strains. Minimal inhibitory concentrations (MICs) of the different molecules ranged from 0.12–0.25 mg/L for prochloraz to more than 16 mg/L for tetraconazole and fenbuconazole. Compared to the F. verticillioides, F. musae MICs were higher suggesting the importance of monitoring the potential future spread of this species also in clinical settings.

In vitro activity of posaconazole and comparators versus opportunistic filamentous fungal pathogens globally collected during 8 years

The epidemiology of invasive filamentous fungal diseases requires monitoring due to changes in susceptibility patterns of new and established antifungal agents that may affect clinical practices. We evaluated the activity of posaconazole against 2,157 invasive moulds collected worldwide from 2010-2017. The isolates included 1,775 Aspergillus spp. and 382 non-Aspergillus moulds, including 81 Fusarium spp., 62 Mucorales group, and 57 Scedosporium spp. Isolates were tested using the CLSI reference broth microdilution method. Posaconazole showed similar activity to itraconazole and voriconazole against A. fumigatus. Applying published ECV, 98.0% of the A. fumigatus and 97.7% to 100.0% of other common Aspergillus species were wildtype to posaconazole. Categorical agreement between posaconazole and the other azoles tested against A. fumigatus was 98.7%. Notably, most of the Aspergillus spp. isolates recovered from this large collection were wildtype to echinocandins and all azoles. Posaconazole non-wildtype rates of A. fumigatus varied across the different geographic regions, with 2.1% in Europe, 2.2% in North America, 1.8% in Latin America, and 0.7% in the Asia-Pacific region. The frequency of azole non-wildtype A. fumigatus isolates from Europe increased steadily from 2010-2017 for all 3 triazoles (0.0%-5.0%). The azole non-wildtype A. fumigatus rates from the other geographic areas were stable over time. Fusarium and/or Scedosporium spp. isolates were highly resistant to azoles and echinocandins. Posaconazole and amphotericin B were the most active agents against the Mucorales. Posaconazole was very active against most species of Aspergillus and was comparable to itraconazole and voriconazole against the less common moulds. Posaconazole should provide a useful addition to the anti-mould grouping of antifungal agents.

Recent developments in less known and multi-resistant fungal opportunists

Fungal infections have increased in recent years due to host factors, such as oncohaematological and transplant-related disorders, immunosuppressive therapy, and AIDS. Additionally, molecular and proteomic facilities have become available to identify previously unrecognizable opportunists. For these reasons, reports on less-known and recalcitrant mycoses, such as those caused by black fungi, hyaline filamentous fungi, coelomycetes, Mucorales, and non-Candida yeasts have emerged. In this review, novel taxonomy in these groups, which often are multi-resistant to one or several classes of antifungals, is discussed. Clinical presentations, diagnosis and current treatment of some major groups are summarised.

PDR Transporter ABC1 Is Involved in the Innate Azole Resistance of the Human Fungal Pathogen Fusarium keratoplasticum

Fusarium keratoplasticum is arguably the most common Fusarium solani species complex (FSSC) species associated with human infections. Invasive fusariosis is a life-threatening fungal infection that is difficult to treat with conventional azole antifungals. Azole drug resistance is often caused by the increased expression of pleiotropic drug resistance (PDR) ATP-binding cassette (ABC) transporters of the ABCG sub-family. Most investigations of Fusarium ABC transporters associated with azole antifungal drug resistance are limited to plant pathogens. Through the manual curation of the entire ABCG protein family of four FSSC species including the fully annotated genome of the plant pathogen Nectria haematococca we identified PDR transporters ABC1 and ABC2 as the efflux pump candidates most likely to be associated with the innate azole resistance phenotype of Fusarium keratoplasticum. An initial investigation of the transcriptional response of logarithmic phase F. keratoplasticum cells to 16 mg/L voriconazole confirmed strong upregulation (372-fold) of ABC1 while ABC2 mRNA levels were unaffected by voriconazole exposure over a 4 h time-period. Overexpression of F. keratoplasticum ABC1 and ABC2 in the genetically modified Saccharomyces cerevisiae host ADΔΔ caused up to ∼1,024-fold increased resistance to a number of xenobiotics, including azole antifungals. Although ABC1 and ABC2 were only moderately (20% and 10%, respectively) expressed compared to the Candida albicans multidrug efflux pump CDR1, overexpression of F. keratoplasticum ABC1 caused even higher resistance levels to certain xenobiotics (e.g., rhodamine 6G and nigericin) than CDR1. Our investigations suggest an important role for ABC1 orthologues in the innate azole resistance phenotype of FSSC species.

Emerging Fungal Infections

Various uncommon fungal pathogens have been increasingly identified as causes of disseminated and invasive fungal disease (IFD) worldwide. Growing recognition and clinical knowledge of these emerging fungal pathogens has occurred through improved molecular diagnostics, nucleic sequence databases, and taxonomic reclassification of medically significant fungi. However, emerging fungal diseases carry significant morbidity and mortality and, due to a paucity of published literature, the collective clinical experience with these fungi is often limited. In this review, we focus on unusual emerging fungal pathogens not extensively covered elsewhere in this issue of Infectious Diseases Clinics of North America.

In vitro activity of olorofim against clinical isolates of the Fusarium oxysporum and Fusarium solani species complexes

BACKGROUND

Invasive fusariosis is associated with marked morbidity and mortality in immunocompromised hosts, and clinical outcomes are poor with conventional therapy. Olorofim (F901318) is an investigational antifungal in the orotomide class that selectively targets fungal dihydroorotate dehydrogenase (DHODH) causing inhibition of pyrimidine biosynthesis.

OBJECTIVE

We evaluated the in vitro activity of olorofim against 61 clinical isolates of the Fusarium oxysporum and F solani species complexes (FOSC and FSSC, respectively), the most prevalent causes of invasive fusariosis.

METHODS

Clinical isolates of FOSC (n = 45) and FSSC (n = 16) were identified using DNA sequence analysis of the translation elongation factor 1-alpha (TEF1α) and RNA polymerase II second largest subunit (RPB2). Antifungal susceptibility testing was performed by CLSI M38 broth microdilution for olorofim, amphotericin B, isavuconazole, posaconazole, voriconazole and micafungin.

RESULTS

Olorofim demonstrated good in vitro activity against both FOSC and FSSC. Against the 45 FOSC isolates, olorofim MICs ranged between 0.03-0.5 mg/L and 0.06->4 mg/L at the 50% and 100% inhibition endpoints, respectively. Against FSSC isolates, olorofim MIC ranged between 0.25-1 mg/L and 1->4 mg/L at 50% and 100% inhibition, respectively. While amphotericin B also demonstrated similar in vitro activity (MIC ranges 1-4 and 0.25-4 mg/L against FOSC and FSSC, respectively), neither the triazoles nor micafungin demonstrated consistent in vitro activity against Fusarium isolates at clinically relevant concentrations.

CONCLUSIONS

The investigational agent olorofim demonstrated good in vitro activity against FOSC and FSSC clinical isolates. Further studies are warranted to determine how well this in vitro activity translates into in vivo efficacy.

Central Nervous System Mold Infections in Children with Hematological Malignancies: Advances in Diagnosis and Treatment

The incidence of invasive mold disease (IMD) has significantly increased over the last decades, and IMD of the central nervous system (CNS) is a particularly severe form of this infection. Solid data on the incidence of CNS IMD in the pediatric setting are lacking, in which Aspergillus spp. is the most prevalent pathogen, followed by mucorales. CNS IMD is difficult to diagnose, and although imaging tools such as magnetic resonance imaging have considerably improved, these techniques are still unspecific. As microscopy and culture have a low sensitivity, non-culture-based assays such as the detection of fungal antigens (e.g., galactomannan or beta-D-glucan) or the detection of fungal nucleic acids by molecular assays need to be validated in children with suspected CNS IMD. New and potent antifungal compounds helped to improve outcome of CNS IMD, but not all agents are approved for children and a pediatric dosage has not been established. Therefore, studies have to rapidly evaluate dosage, safety and efficacy of antifungal compounds in the pediatric setting. This review will summarize the current knowledge on diagnostic tools and on the management of CNS IMD with a focus on pediatric patients.

Invasive Fusariosis in Nonneutropenic Patients, Spain, 2000-2015

Invasive fusariosis (IF) is associated with severe neutropenia in patients with concurrent hematologic conditions. We conducted a retrospective observational study to characterize the epidemiology of IF in 18 Spanish hospitals during 2000-2015. In that time, the frequency of IF in nonneutropenic patients increased from 0.08 cases per 100,000 admissions in 2000-2009 to 0.22 cases per 100,000 admissions in 2010-2015. Nonneutropenic IF patients often had nonhematologic conditions, such as chronic cardiac or lung disease, rheumatoid arthritis, history of solid organ transplantation, or localized fusariosis. The 90-day death rate among nonneutropenic patients (28.6%) and patients with resolved neutropenia (38.1%) was similar. However, the death rate among patients with persistent neutropenia (91.3%) was significantly higher. We used a multivariate Cox regression analysis to characterize risk factors for death: persistent neutropenia was the only risk factor for death, regardless of antifungal therapy.

Transcriptional response of Fusarium oxysporum and Neocosmospora solani challenged with amphotericin B or posaconazole

Some species of fusaria are well-known pathogens of humans, animals and plants. Fusarium oxysporum and Neocosmospora solani (formerly Fusarium solani) cause human infections that range from onychomycosis or keratitis to severe disseminated infections. In general, these infections are difficult to treat due to poor therapeutic responses in immunocompromised patients. Despite that, little is known about the molecular mechanisms and transcriptional changes responsible for the antifungal resistance in fusaria. To shed light on the transcriptional response to antifungals, we carried out the first reported high-throughput RNA-seq analysis for F. oxysporum and N. solani that had been exposed to amphotericin B (AMB) and posaconazole (PSC). We detected significant differences between the transcriptional profiles of the two species and we found that some oxidation-reduction, metabolic, cellular and transport processes were regulated differentially by both fungi. The same was found with several genes from the ergosterol synthesis, efflux pumps, oxidative stress response and membrane biosynthesis pathways. A significant up-regulation of the C-22 sterol desaturase (ERG5), the sterol 24-C-methyltransferase (ERG6) gene, the glutathione S-transferase (GST) gene and of several members of the major facilitator superfamily (MSF) was demonstrated in this study after treating F. oxysporum with AMB. These results offer a good overview of transcriptional changes after exposure to commonly used antifungals, highlights the genes that are related to resistance mechanisms of these fungi, which will be a valuable tool for identifying causes of failure of treatments.

Human fusariosis: An emerging infection that is difficult to treat

Fusarium spp. has been associated with a broad spectrum of emerging infections collectively termed fusariosis. This review includes articles published between 2005 and 2018 that describe the characteristics, clinical management, incidence, and emergence of these fungal infections. Fusarium solani and F. oxysporum are globally distributed and represent the most common complexes. Few therapeutic options exist due to intrinsic resistance, especially for the treatment of invasive fusariosis. Therefore, the use of drug combinations could be an important alternative for systemic antifungal resistance. Increase in the number of case reports on invasive fusariosis between 2005 and 2018 is evidence of the emergence of this fungal infection.

A 23 bp cyp51A Promoter Deletion Associated With Voriconazole Resistance in Clinical and Environmental Isolates of Neocosmospora keratoplastica

In the fungal pathogen Aspergillus fumigatus, resistance to azole antifungals is often linked to mutations in CYP51A, a gene that encodes the azole antifungal drug target lanosterol 14α-demethylase. The aim of this study was to investigate whether similar changes could be associated with azole resistance in a Malaysian Fusarium solani species complex (FSSC) isolate collection. Most (11 of 15) clinical FSSC isolates were Neocosmospora keratoplastica and the majority (6 of 10) of environmental isolates were Neocosmospora suttoniana strains. All 25 FSSC isolates had high minimum inhibitory concentrations (MICs) for itraconazole and posaconazole, low MICs for amphotericin B, and various (1 to >32 mg/l) voriconazole susceptibilities. There was a tight association between a 23 bp CYP51A promoter deletion and high (>32 mg/l) voriconazole MICs; of 19 FSSC strains sequenced, nine isolates had voriconazole MICs > 32 mg/l, and they all contained the 23 bp CYP51A promoter deletion, although it was absent in the ten remaining isolates with low (≤12 mg/l) voriconazole MICs. Surprisingly, this association between voriconazole resistance and the 23 bp CYP51A promoter deletion held true across species boundaries. It was randomly distributed within and across species boundaries and both types of FSSC isolates were found among environmental and clinical isolates. Three randomly selected N. keratoplastica isolates with low (≤8 mg/l) voriconazole MICs had significantly lower (1.3–7.5 times) CYP51A mRNA expression levels than three randomly selected N. keratoplastica isolates with high (>32 mg/l) voriconazole MICs. CYP51A expression levels, however, were equally strongly induced (~6,500-fold) by voriconazole in two representative strains reaching levels, after 80 min of induction, that were comparable to those of CYP51B. Our results suggest that FSSC isolates with high voriconazole MICs have a 23 bp CYP51A promoter deletion that provides a potentially useful marker for voriconazole resistance in FSSC isolates. Early detection of possible voriconazole resistance is critical for choosing the correct treatment option for patients with invasive fusariosis.

Molecular identification of Fusarium species complex isolated from clinical samples and its antifungal susceptibility patterns

Background and Purpose:

More than 300 Fusarium species are grouped into approximately 23 species complexes out of which around 70 are involved in human infections. The nomenclature of these species has undergone considerable changes in recent years. These species cause localized infections in individuals while inducing systemic infections mainly in immunocompromised patients. The present study was conducted to identify Fusarium species in clinical isolates by molecular methods and determine their in vitro minimum inhibitory concentration (MIC) patterns to address the lack of data in this domain in Northern India.

Materials and Methods:

For the purpose of the study, Fusarium isolates obtained from various clinical samples were sent to the Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands, for molecular identification. The MIC testing was performed using the microbroth dilution method as per the Clinical and Laboratory Standards Institute reference method (M38-A2).

Results:

Fusarium was isolated from 33 patients (i.e., 1, 1, 2, 14, and 15 cases with endophthalmitis, sinusitis, pulmonary involvement, onychomycosis, and keratitis, respectively). These 33 isolates belonged to three species complexes, namely F. solani species complex (FSSC; n=13), F. fujikuroi species complex (FFSC; n=13), and F. incarnatumequiseti species complex (FIESC; n=7). The species identified within FSSC, FFSC, and FIESC included F. keratoplasticum (n=6)/F. falciforme (n=6)/F. solani (n=1), F. proliferatum (n=7)/F. sacchari (n=5)/F. anthophilum (n=1), and F. incarnatum SC species (n=6)/F. equiseti SC species (n=1), respectively. The MIC results showed that all isolates had a lower MIC against amphotericin B than against the other antifungal agents.

In Vitro Susceptibility of Fusarium to Isavuconazole

To evaluate the in vitro susceptibility of Fusarium to isavuconazole, 75 clinical isolates were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry and then tested with a broth microdilution method (EUCAST) and the gradient concentration strip (GCS) technique. The activity of isavuconazole overall was shown to be limited, with an MIC₅₀ of >16 μg/ml, without significant differences between the species complexes. The categorical agreement between GCS and EUCAST was 97.4% to 100%, making the GCS as a valuable alternative.

Antifungal Susceptibly Testing by Concentration Gradient Strip Etest Method for Fungal Isolates: A Review

Antifungal susceptibility testing is an important tool for managing patients with invasive fungal infections, as well as for epidemiological surveillance of emerging resistance. For routine testing in clinical microbiology laboratories, ready-to-use commercial methods are more practical than homemade reference techniques. Among commercially available methods, the concentration gradient Etest strip technique is widely used. It combines an agar-based diffusion method with a dilution method that determinates a minimal inhibitory concentration (MIC) in µg/mL. Many studies have evaluated the agreement between the gradient strip method and the reference methods for both yeasts and filamentous fungi. This agreement has been variable depending on the antifungal, the species, and the incubation time. It has also been shown that the gradient strip method could be a valuable alternative for detection of emerging resistance (non-wild-type isolates) as Etest epidemiological cutoff values have been recently defined for several drug-species combinations. Furthermore, the Etest could be useful for direct antifungal susceptibility testing on blood samples and basic research studies (e.g., the evaluation of the in vitro activity of antifungal combinations). This review summarizes the available data on the performance and potential use of the gradient strip method.

A consensus document for the clinical management of invasive fungal diseases in pediatric patients with hematologic cancer and/or undergoing hematopoietic stem cell transplantation in Brazilian medical centers

In the present paper we summarize the suggestions of a multidisciplinary group including experts in pediatric oncology and infectious diseases who reviewed the medical literature to elaborate a consensus document (CD) for the diagnosis and clinical management of invasive fungal diseases (IFDs) in children with hematologic cancer and those who underwent hematopoietic stem-cell transplantation. All major multicenter studies designed to characterize the epidemiology of IFDs in children with cancer, as well as all randomized clinical trials addressing empirical and targeted antifungal therapy were reviewed. In the absence of randomized clinical trials, the best evidence available to support the recommendations were selected. Algorithms for early diagnosis and best clinical management of IFDs are also presented. This document summarizes practical recommendations that will certainly help pediatricians to best treat their patients suffering of invasive fungal diseases.

Epidemiological aspects and characterization of the resistance profile of Fusarium spp. in patients with invasive fusariosis

Introduction. The remarkable intrinsic resistance of Fusarium species to most antifungal agents results in high mortality rates in the immunocompromised population.Aims. This study aimed to investigate the epidemiology, clinical features and antifungal susceptibility of Fusarium isolates in patients with invasive fusariosis.Methodology. A total of 27 patients admitted to a referral hospital from January 2008 to June 2017 were evaluated. Antifungal susceptibility testing of isolates was performed by broth microdilution according to the Clinical and Laboratory Standards Institute guidelines.Results. Haematological malignancy was the predominant underlying condition, with an incidence of invasive fusariosis of 14.8 cases per 1000 patients with acute lymphoid leukaemia and 13.1 cases per 1000 patients with acute myeloid leukaemia. The Fusarium solani species complex (FSSC) was the most frequent agent group, followed by the Fusarium oxysporum species complex (FOSC). Voriconazole showed the best activity against Fusarium, followed by amphotericin B. Itraconazole showed high minimum inhibitory concentration values, indicating in vitro resistance. Clinical FSSC isolates were significantly (P<0.05) more resistant to amphotericin B and voriconazole than FOSC isolates.Conclusion. The present antifungal susceptibility profiles indicate a high incidence of fusariosis in patients with haematological malignancy. Species- and strain-specific differences in antifungal susceptibility exist within Fusarium in this setting.

Emerging Fungal Infections: New Patients, New Patterns, and New Pathogens

The landscape of clinical mycology is constantly changing. New therapies for malignant and autoimmune diseases have led to new risk factors for unusual mycoses. Invasive candidiasis is increasingly caused by non-albicans Candida spp., including C. auris, a multidrug-resistant yeast with the potential for nosocomial transmission that has rapidly spread globally. The use of mould-active antifungal prophylaxis in patients with cancer or transplantation has decreased the incidence of invasive fungal disease, but shifted the balance of mould disease in these patients to those from non-fumigatus Aspergillus species, Mucorales, and Scedosporium/Lomentospora spp. The agricultural application of triazole pesticides has driven an emergence of azole-resistant A. fumigatus in environmental and clinical isolates. The widespread use of topical antifungals with corticosteroids in India has resulted in Trichophyton mentagrophytes causing recalcitrant dermatophytosis. New dimorphic fungal pathogens have emerged, including Emergomyces, which cause disseminated mycoses globally, primarily in HIV infected patients, and Blastomyceshelicus and B. percursus, causes of atypical blastomycosis in western parts of North America and in Africa, respectively. In North America, regions of geographic risk for coccidioidomycosis, histoplasmosis, and blastomycosis have expanded, possibly related to climate change. In Brazil, zoonotic sporotrichosis caused by Sporothrix brasiliensis has emerged as an important disease of felines and people.

Successful treatment of disseminated fusariosis in a patient with acute lymphoblastic leukemia: A case report and literature review

RATIONALE

Fusarium is the second most common cause of fungi infections in the immunocompromised patients with the mortality rate over 80%. Early identification and appropriate selection of antifungal drugs is the key to successful treatment.

PATIENT CONCERNS

A 31-year-old female was diagnosed with acute lymphocytic leukemia (pro-B ALL). She developed a high fever and presented with typical painful purple nodules with central necrosis formed on the upper and lower limbs during the induction chemotherapy.

DIAGNOSIS

Combining clinical manifestations with results of blood culture testing and sequencing methods, it was consistent with the diagnosis of disseminated fusariosis.

INTERVENTIONS

The patient was treated with the combination of tigecycline and antifungal agents (Liposomal Amphotericin B and Voriconazole), OUTCOMES:: The skin lesions generally healed with some scar left after treating with antifungal agents for 6 weeks. The final date of follow-up was 1.5 years later, and the patient was alive with no diseases.

LESSONS

This case highlights the importance of the typical cutaneous lesions for early diagnosis and proper treatment to decrease the mortality rate of this severe infection. This patient was successfully treated with the combination of tigecycline and antifungal agents, which may be the first clinical confirmation of tigecycline that improved the effectiveness of antifungal agents against fusariosis, but it requires more studies to verify. We reviewed 62 cases from literature and analyzed using logistic regression and recognized the high-risk factor for fusariosis mortality in patients with acute leukemia was non-remission of underlying disease.

Broad spectrum triazoles for invasive mould infections in adults: Which drug and when?

Invasive mould infections are an increasing cause of morbidity and mortality globally, mainly due to increasing numbers of immunocompromised individuals at risk for fungal infections. The introduction of broad spectrum triazoles, which are much better tolerated compared to conventional amphotericin B formulations, has increased survival, particularly in invasive mould infection. However, early initiation of appropriate antifungal treatment remains a major predictor of outcome in invasive mould infection, but despite significant advances in diagnosis of these diseases, early diagnosis remains a challenge. As a result, prophylaxis with mould-active triazoles is widely used for those patients at highest risk for invasive mould infection, including patients with prolonged neutropenia after induction chemotherapy for acute myeloid leukemia and patients with graft-versus-host-disease. Posaconazole is the recommended drug of choice for antimould prophylaxis in these high-risk patients. Voriconazole has its primary role in treatment of invasive aspergillosis but not in prophylaxis. Recently, isavuconazole has been introduced as an excellent alternative to voriconazole for primary treatment of invasive aspergillosis in patients with hematological malignancies. Compared to voriconazole, isavuconazole and posaconazole have broader activity against moulds and are therefore also an option for treatment of mucormycosis in the presence of intolerance or contraindications against liposomal amphotericin B.

Epidemiology of antifungal susceptibility: Review of literature

Fungal infections are a major cause of morbidity and mortality despite the latest developments of diagnostic tools and therapeutic options. Early initiation of the appropriate antifungal therapy has been demonstrated to have a direct impact on the patient's outcome. Antifungal susceptibility testing methods are available to detect antifungal resistance and to determine the best treatment for a specific fungus. American and European standards have been developed, as well as equivalent commercial systems, which are more appropriate for clinical laboratories. These studies have allowed the development of interpretative breakpoints against the most frequent agents of fungal infections in the world. Surveillance of antifungal susceptibility patterns can provide the local drug resistance data to the clinicians, which can further aid better management of patients. Antifungal susceptibility tests have become essential tools to identify resistance to antifungals, to know the local and global disease epidemiology and to guide the treatment of fungal diseases. The distribution of species and the prevalence of antifungal resistance in fungi isolates varied among different areas. Here we summarize the epidemiology of antifungal susceptibility pattern of different fungal species.

Estimated Burden of Serious Fungal Diseases in Serbia

For the first time, we aimed to estimate the burden of serious fungal infections or diseases (SFD) and highlight national epidemiological features in Serbia. Data on population and underlining conditions were extracted from the Statistical Office of the Republic of Serbia, World Bank, the Institute of Public Health of Serbia, the World Health Organization, National reference laboratory for medical mycology, the national registries of Serbian professional societies, and relevant publications. The population structure/inhabitants in 2016 (not including the autonomous region Kosovo & Metohija) was 7,058,322; with 6,041,743 adults (85.6%). The populations at risk (total cases per year) were: HIV infected 2441; acute myeloid leukemia 212; stem cell transplantation 151; solid organ transplants 59; chronic obstructive pulmonary disease 250,302; adult asthmatics 311,806; adult cystic fibrosis 65; pulmonary tuberculosis 898; lung cancer 7260; intensive care unit admissions 19,821; and renal support 520. Annual fungal disease cases estimated are: candidemia 518; invasive aspergillosis 619; Candida peritonitis 187; Pneumocystis jirovecii pneumonia 62; cryptococcosis 5; mucormycosis or fusariosis 23; severe asthma with fungal sensitization 10,393; allergic bronchopulmonary aspergillosis 9094; chronic pulmonary aspergillosis 448, recurrent Candida vaginitis 135,303; oral candidiasis 208,489; esophageal candidiasis 173, fungal keratitis 70; tinea capitis 300; and onychomycosis 342,721. We expect that 156,825 people suffer from serious SFD each year (2221/100,000), and 409 dies annually. Additionally, the prevalence of superficial infections exceeds 1,008,995 cases (14,295/100,000). The first Rhinosporidium outbreak in Europe was associated with Serbian Silver Lake. The plant pathogen Fusarium seems to be emerging in Serbian pediatric haematooncology settings. Candida auris and endemic mycoses have not been observed to date. These general estimates provide a primer for further efforts to study fungal epidemiology in Serbia.

Lack of correlation of ECV and outcome in an in vivo murine model of systemic fusariosis

The efficacy of liposomal amphotericin B and voriconazole was evaluated against the systemic infection by Fusarium oxysporum species complex or Fusarium keratoplasticum. Although MIC values were within the epidemiological cutoff values (ECVs) recently stablished for Fusarium spp., no efficacy was obtained, indicating that ECVs for Fusarium are not relevant for in vivo efficacy.

Potent Activities of Luliconazole, Lanoconazole, and Eight Comparators against Molecularly Characterized Fusarium Species

A collection of clinical (n = 47) and environmental (n = 79) Fusarium isolates were tested against 10 antifungal drugs, including 2 novel imidazoles. Luliconazole and lanoconazole demonstrated very low geometric mean MIC values of 0.005 and 0.013 μg/ml, respectively, compared with 0.51 μg/ml for micafungin, 0.85 μg/ml for efinaconazole, 1.12 μg/ml for natamycin, 1.18 μg/ml for anidulafungin, 1.31 μg/ml for voriconazole, 1.35 μg/ml for caspofungin, 1.9 μg/ml for amphotericin B, and 4.08 μg/ml for itraconazole. Results show that these drugs are potential candidates for (topical) treatment of skin and nail infections due to Fusarium species.

Identification and Characterization of Fusarium proliferatum, a New Species of Fungi that Cause Fungal Keratitis

Fusarium proliferatum (F. proliferatum) is known as a pathogen of corn and other crops, but its role in fungal keratitis has not been well investigated. Among 877 Fusarium isolates, we identified 155 (17.7%) stains as F. proliferatum according to their morphological features and partial DNA sequencing of translation elongation factor-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1\alpha $$\end{document}1α (EF-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1\alpha $$\end{document}1α) in this study. In vitro antifungal susceptibility tests showed that the F. proliferatum strains were sensitive to natamycin and vorionazole but resistant to amphotericin B, fluconazol, ketoconazole and itaconazole. Most of the F. proliferatum-positive keratitis patients (44/155,28.4%) were aged 51–60 years old. The main cause of infection was injury by a plant (51/155, 32.9%). A combination of 1% amphotericin B and 3% ketoconazole cured 45.2% (14/31) and a combination of 0.5% natamycin and 0.5% voriconazole cured 59.1% (13/22) of F. proliferatum-positive patients. The date suggests that F. proliferatum identified through EF-1ɑ DNA sequencing is an important new species that causes fungal keratitis. Based on antifungal susceptibility, treatment with a combination of 0.5% natamycin and 0.5% voriconazole improves the therapeutic efficacy in F. prolifertum-positive patients.

Fusarium riograndense sp. nov., a new species in the Fusarium solani species complex causing fungal rhinosinusitis

Invasive fusariosis has a high mortality and is predominantly observed in patients with leukemia. We report the first case of a novel species of Fusarium, Fusarium riograndense sp. nov, isolated from a lesion in the nasal cavity lesion of a patient with acute lymphoblastic leukemia. The etiological agent was identified by Multilocus Sequencing Typing (MLST), including RPB2, TEF-1α, and ITS-LSU sequences, the gold standard technique to identify new species of Fusarium. MLST and phenotypic data strongly supported its inclusion in the F. solani species complex (FSSC). The new species produced a red pigment in the Sabouraud Dextrose Agar similar to other members of the complex. The macroconiodia developed from phialides on multibranched conidiophores which merge to form effuse sporodochia with a basal foot-cell instead of papilla in basal cell shape. The microconidia were ellipsoidal, 0-1-septated, produced from long monophialides. Chlamydospores were produced singly or in pairs. Amphotericin B (MIC 1μg/mL) was the most active drug, followed by voriconazole (MIC 8μg/mL). The patient was successfully treated with voriconazole. Our findings indicate another lineage within FSSC capable causing of invasive human infection.

Rare fungal infectious agents: a lurking enemy

In the expanding population of immunocompromised patients and those treated in intensive care units, rare fungal infectious agents have emerged as important pathogens, causing invasive infections associated with high morbidity and mortality. These infections may present either as de novo or as breakthrough invasive infections in high-risk patients with hematologic malignancies receiving prophylactic or empirical antifungal therapy or in patients with central venous catheters. Diagnosis and treatment are challenging. Physicians should have a high index of suspicion because early diagnosis is of paramount importance. Conventional diagnostic methods such as cultures and histopathology are still essential, but rapid and more specific molecular techniques for both detection and identification of the infecting pathogens are being developed and hopefully will lead to early targeted treatment. The management of invasive fungal infections is multimodal. Reversal of risk factors, if feasible, should be attempted. Surgical debridement is recommended in localized mold infections. The efficacy of various antifungal drugs is not uniform. Amphotericin B is active against most yeasts, except Trichosporon, as well as against Mucorales, Fusarium, and some species of Paecilomyces and dimorphic fungi. The use of voriconazole is suggested for the treatment of trichosporonosis and scedosporiosis. Combination treatment, though recommended as salvage therapy in some infections, is controversial in most cases. Despite the use of available antifungals, mortality remains high. The optimization of molecular-based techniques, with expansion of reference libraries and the possibility for direct detection of resistance mechanisms, is awaited with great interest in the near future. Further research is necessary, however, in order to find the best ways to confront and destroy these lurking enemies.

Pharmacodynamic studies of voriconazole: informing the clinical management of invasive fungal infections

INTRODUCTION

Voriconazole is a broad-spectrum antifungal agent commonly used to treat invasive fungal infections (IFI), including aspergillosis, candidiasis, Scedosporium infection, and Fusarium infection. IFI often occur in immunocompromised patients, leading to increased morbidity and mortality.

AREAS COVERED

The objective of this review is to summarize the pharmacodynamic properties of voriconazole and to provide considerations for potential optimal dosing strategies. Studies have demonstrated superior clinical response when an AUC/MIC >25 or Cmin/MIC >1 is attained in adult patients, correlating to a trough concentration range as narrow as 2-4.5 mg/L; however, these targets are poorly established in the pediatric population. Topics in this discussion include voriconazole use in multiple age groups, predisposing patient factors for IFI, and considerations for clinicians managing IFI. Expert commentary: The relationship between voriconazole dosing and exposure is not well defined due to the large inter- and intra-subject variability. Development of comprehensive decision support tools for individualizing dosing, particularly in children who require higher dosing, will help to increase the probability of achieving therapeutic efficacy and decrease sub-therapeutic dosing and adverse events.

First description of spontaneous fungal peritonitis caused by Fusarium solani in a critically ill patient with liver cirrhosis

Fusarium spp., common soil moulds, are emerging fungal pathogens in immunocompromised subjects. We report the first case of Fusarium solani peritonitis in a patient with liver cirrhosis. Because of the high morbidity and mortality associated with fusariosis, an aggressive approach to treatment as well as identification of the species and drug susceptibilities is warranted.

Reduced Multidrug Susceptibility Profile Is a Common Feature of Opportunistic Fusarium Species: Fusarium Multi-Drug Resistant Pattern

The resistance among various opportunistic Fusarium species to different antifungal agents has emerged as a cause of public health problems worldwide. Considering the significance of multi-drug resistant (MDR), this paper emphasizes the problems associated with MDR and the need to understand its clinical significance to combat microbial infections. The search platform PubMed/MEDLINE and a review of 32 cases revealed a common multidrug-resistant profile exists, and clinically relevant members of Fusarium are intrinsically resistant to most currently used antifungals. Dissemination occurs in patients with prolonged neutropenia, immune deficiency, and especially hematological malignancies. Amphotericin B displayed the lowest minimum inhibitory concentrarions (MICs) followed by voriconazole, and posaconazole. Itraconazole and fluconazole showed high MIC values, displaying in vitro resistance. Echinocandins showed the highest MIC values. Seven out of ten (70%) patients with neutropenia died, including those with fungemia that progressed to skin lesions. Clinical Fusarium isolates displayed a common MDR profile and high MIC values for the most available antifungal agents with species- and strain-specific differences in antifungal susceptibility. Species identification of Fusarium infections is important. While the use of natamycin resulted in a favorable outcome in keratitis, AmB and VRC are the most used agents for the treatment of fusariosis in clinical settings.

Comparison of DNA Microarray, Loop-Mediated Isothermal Amplification (LAMP) and Real-Time PCR with DNA Sequencing for Identification of Fusarium spp. Obtained from Patients with Hematologic Malignancies

The performance of three molecular biology techniques, i.e., DNA microarray, loop-mediated isothermal amplification (LAMP), and real-time PCR were compared with DNA sequencing for properly identification of 20 isolates of Fusarium spp. obtained from blood stream as etiologic agent of invasive infections in patients with hematologic malignancies. DNA microarray, LAMP and real-time PCR identified 16 (80%) out of 20 samples as Fusarium solani species complex (FSSC) and four (20%) as Fusarium spp. The agreement among the techniques was 100%. LAMP exhibited 100% specificity, while DNA microarray, LAMP and real-time PCR showed 100% sensitivity. The three techniques had 100% agreement with DNA sequencing. Sixteen isolates were identified as FSSC by sequencing, being five Fusarium keratoplasticum, nine Fusarium petroliphilum and two Fusarium solani. On the other hand, sequencing identified four isolates as Fusarium non-solani species complex (FNSSC), being three isolates as Fusarium napiforme and one isolate as Fusarium oxysporum. Finally, LAMP proved to be faster and more accessible than DNA microarray and real-time PCR, since it does not require a thermocycler. Therefore, LAMP signalizes as emerging and promising methodology to be used in routine identification of Fusarium spp. among cases of invasive fungal infections.