The emerging role of Fusarium infections in patients with cancer

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.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Fusarium-Induced Cellulitis in an Immunocompetent Patient With Sickle Cell Disease: A Case Report

Fungal infections due to Fusarium species are mostly present in immunocompromised and patients with poorly controlled diabetes mellitus. We report a case of lower extremity skin infection caused by Fusarium species in a 61-year-old woman diagnosed with sickle cell disease. Single skin ulceration caused by Fusarium species can result from fungal inoculation into damaged tissue, so any condition that damages the skin can be considered as a risk factor for inoculation. Long-standing sickle cell disease may develop vaso-occlusion in the skin that can produce lower extremity ulcers and myofascial syndromes. The mechanism is not completely characterized, but compromised blood flow, endothelial dysfunction, thrombosis, inflammation, and delayed healing are thought to contribute to locally compromised tissue that may eventually lead to opportunistic infection such as in our case. Other factors contribute to the pathophysiology of lower extremity ulcers such as diabetes mellitus, with the resulting peripheral vascular ischemia causing poor circulation to the lower extremity, and peripheral neuropathy, which can make patients with diabetes unaware of minor trauma leading to the development of skin infections.

Fusarium Peritonitis in a Child on Peritoneal Dialysis: Case Report and Review of the Literature

Objective

To review various aspects of the management of peritonitis due to Fusarium, a soil mold which infrequently causes infections in humans.

Data Sources

A case of Fusarium peritonitis in a child on chronic peritoneal dialysis (PD) is presented. The child developed Fusarium peritonitis 2 weeks after an episode of bacterial peritonitis. His Tenckhoff catheter was removed, and he was maintained on hemodialysis while receiving intravenous amphotericin. Following 2 weeks of treatment with amphotericin, he was successfully returned to PD. A literature review of all previously reported cases of Fusarium peritonitis was then conducted to determine features common to infections caused by Fusarium. Emphasis was also placed on unique characteristics of the organism that may affect patient management, as well as patient characteristics that may increase the risk for infection by Fusarium.

Results

Fusarium may cause infection inimmuno suppressed individuals, such as cancer patients or patients on chronic PD. The organism has a propensity to attach to foreign bodies such as intravascular and intraperitoneal catheters. Therefore, successful treatment of infections caused by Fusarium may require catheter removal in addition to systemic antifungal therapy.

Conclusions

This report presents the first known case of Fusarium peritonitis in a child. In view of the difficulties posed by this unusual organism, optimal therapy of Fusarium peritonitis should consist of immediate catheter removal and treatment with systemic antifungal drugs.

Impact of Surgical Treatment on Paranasal Fungal Infections in Bone Marrow Transplant Patients

Invasive fungal sinusitis can develop in immunosuppressed patients. A more complex problem is immunosuppressed patients who have undergone bone marrow transplantation. For a prolonged period, they are both neutropenic and thrombocytopenic. Survival in these patients is poor, and the role for extensive surgical intervention for sinus disease has to be weighed against the risk and the potential that this is a systemic disease. Between January 1983 and June 1993, 29 bone marrow transplant recipients with documented invasive fungal infections of the sinuses and paranasal tissues required surgical intervention. This represents 1.7% of the total 1692 bone marrow transplants performed. There were 22 allogeneic, 6 autologous, and 3 unrelated donor transplants, with two patients receiving two separate grafts. Underlying diseases included 24 hematologic malignancies and 5 other disorders, including 1 aplastic anemia and 1 solid tumor. The mortality rate from the initial fungal infection was 62%. Twenty-seven percent resolved the initial infections but subsequently died of other causes. All patients received medical management, such as amphotericin, rifampin, and colony-stimulating factors, in addition to surgical intervention. Surgical management ranged from minimally invasive procedures to extensive resections including medial maxillectomies. Sixty-one percent of the patients who died of the initial infection had undergone extensive surgical procedures versus 55% of those who resolved the infection. Recovery of neutrophil counts was required to clear the infection but did not necessarily predict a good outcome because 50% of those who died of the infection had experienced neutrophil recovery. White blood cell counts at the time of surgery were not significantly different between the two groups. Prognosis was poor when cranial and orbital involvement and/or bony erosion occurred.

MIC Distributions and Evaluation of Fungicidal Activity for Amphotericin B, Itraconazole, Voriconazole, Posaconazole and Caspofungin and 20 Species of Pathogenic Filamentous Fungi Determined Using the CLSI Broth Microdilution Method

For filamentous fungi (moulds), species-specific interpretive breakpoints and epidemiological cut-off values (ECVs) have only been proposed for a limited number of fungal species-antifungal agent combinations, with the result that clinical breakpoints are lacking for most emerging mould pathogens. In the current study, we have compiled minimum inhibitory concentration (MIC) data for 4869 clinical mould isolates and present full MIC distributions for amphotericin B, itraconazole, voriconazole, posaconazole, and caspofungin with these isolates which comprise 20 species/genera. In addition, we present the results of an assessment of the fungicidal activity of these same five antifungal agents against a panel of 123 mould isolates comprising 16 of the same species.

Diagnosis of Fusarium Infections: Approaches to Identification by the Clinical Mycology Laboratory

Infections caused by the genus Fusarium have emerged over the past decades and range from onychomycosis and keratitis in healthy individuals to deep and disseminated infections with high mortality rates in immune-compromised patients. As antifungal susceptibility can differ between the different Fusarium species, identification at species level is recommended. Several clinical observations as hyaline hyphae in tissue, necrotic lesions in the skin and positive blood tests with fungal growth or presence of fungal cell wall components may be the first hints for fusariosis. Many laboratories rely on morphological identification, but especially multi-locus sequencing proves better to discriminate among members of the species complexes involved in human infection. DNA-based diagnostic tools have best discriminatory power when based on translation elongation factor 1-α or the RNA polymerase II second largest subunit. However, assays based on the detection of other fusarial cell compounds such as peptides and cell wall components may also be used for identification. The purpose of this review is to provide an overview and a comparison of the different tools currently available for the diagnosis of fusariosis.

Intracranial fusarium fungal abscess in an immunocompetent patient: case report and review of the literature

Introduction Fusarium spp is an omnipresent fungal species that may lead to fatal infections in immunocompromised populations. Spontaneous intracranial infection by Fusarium spp in immunocompetent individuals is exceedingly rare.

Case Report An immunocompetent 33-year-old Hispanic woman presented with persistent headaches and was found to have a contrast-enhancing mass in the left petrous apex and prepontine cistern. She underwent a subsequent craniotomy for biopsy and partial resection that revealed a Fusarium abscess. She had a left transient partial oculomotor palsy following the operation that resolved over the next few weeks. She was treated with long-term intravenous antifungal therapy and remained at her neurologic baseline 18 months following the intervention.

Discussion To our knowledge, this is the first reported case of Fusarium spp brain abscess in an immunocompetent patient. Treatment options include surgical intervention and various antifungal medications.

Conclusion This case demonstrates the rare potential of intracranial Fusarium infection in the immunocompetent host, as well as its successful treatment with surgical aspiration and antifungal therapy.

Infections Caused byFusariumSpecies

Fusariosis, an emerging opportunistic mycosis caused by Fusarium species, carries a high mortality rate in immunocompromised patients. The dismal prognosis of patients with fusariosis is aggravated by the limited therapeutic options. Here we give an overview of the epidemiology, pathogenesis, clinical manifestations, antifungal susceptibility and management of fusariosis.

In VitroTesting ofAspergillus fumigatusClinical Isolates for Susceptibility to Voriconazole, Amphotericin B and Itraconazole: Comparison of Sensititre versus NCCLS M38-A Using Two Different Inocula

Voriconazole, amphotericin B and itraconazole were tested in vitro against 18 strains of Aspergillus fumigatus isolated from cystic fibrosis patients. Susceptibility was tested with the broth microdilution method (M38-A protocol-NCCLS). Results of this reference method were compared with those of an experimental commercial microdilution broth method (Sensititre). Two different inocula, prepared from 2- and 7-day cultures, were used. Minimum inhibitory concentrations (MICs) of the reference method ranged from 0.25 to 2 microg/ml for voriconazole, 0.06 to 1 microg/ml for amphotericin B, 0.016 to >16 microg/ml for itraconazole. There were no significant differences in the MIC ranges or MIC90 values obtained with the two testing methods or with the two types of inocula. These findings confirm the good in vitro activity of voriconazole, itraconazole and amphotericin B against A. fumigatus. They also indicate that reliable susceptibility data can be generated more rapidly by commercial systems and use of 2-day cultures for inoculum preparation.

Emerging systemic fungal infections

Systemic mycoses are a heterogeneous group of infections caused by different species of fungi that mainly affect individuals with primary or secondary alterations of immunity. In recent years, there has been an increase in the incidence of infections related to migration, AIDS, and other causes of immunosuppression, such as solid organ and bone marrow transplantation; oncological, hematological, and autoimmune diseases; and the use of new drugs. In this paper, we outline the microbiological and epidemiological characteristics of 3 fungi: Aspergillus spp, Fusarium spp, and Penicillium spp. We describe the clinical manifestations of disease with emphasis on those that should alert the dermatologist to make an early diagnosis. We detail the various tools for early diagnosis, prevention, and the epidemiology of different antifungals available for treatment and their mechanism of action and therapeutic efficacy.

Cyber infrastructure for Fusarium: three integrated platforms supporting strain identification, phylogenetics, comparative genomics and knowledge sharing

The fungal genus Fusarium includes many plant and/or animal pathogenic species and produces diverse toxins. Although accurate species identification is critical for managing such threats, it is difficult to identify Fusarium morphologically. Fortunately, extensive molecular phylogenetic studies, founded on well-preserved culture collections, have established a robust foundation for Fusarium classification. Genomes of four Fusarium species have been published with more being currently sequenced. The Cyber infrastructure for Fusarium (CiF; http://www.fusariumdb.org/) was built to support archiving and utilization of rapidly increasing data and knowledge and consists of Fusarium-ID, Fusarium Comparative Genomics Platform (FCGP) and Fusarium Community Platform (FCP). The Fusarium-ID archives phylogenetic marker sequences from most known species along with information associated with characterized isolates and supports strain identification and phylogenetic analyses. The FCGP currently archives five genomes from four species. Besides supporting genome browsing and analysis, the FCGP presents computed characteristics of multiple gene families and functional groups. The Cart/Favorite function allows users to collect sequences from Fusarium-ID and the FCGP and analyze them later using multiple tools without requiring repeated copying-and-pasting of sequences. The FCP is designed to serve as an online community forum for sharing and preserving accumulated experience and knowledge to support future research and education.

Fusarium infection in lung transplant patients: report of 6 cases and review of the literature

Fusarium is a fungal pathogen of immunosuppressed lung transplant patients associated with a high mortality in those with severe and persistent neutropenia. The principle portal of entry for Fusarium species is the airways, and lung involvement almost always occurs among lung transplant patients with disseminated infection. In these patients, the immunoprotective mechanisms of the transplanted lungs are impaired, and they are, therefore, more vulnerable to Fusarium infection. As a result, fusariosis occurs in up to 32% of lung transplant patients. We studied fusariosis in 6 patients following lung transplantation who were treated at Massachusetts General Hospital during an 8-year period and reviewed 3 published cases in the literature. Cases were identified by the microbiology laboratory and through discharge summaries. Patients presented with dyspnea, fever, nonproductive cough, hemoptysis, and headache. Blood tests showed elevated white blood cell counts with granulocytosis and elevated inflammatory markers. Cultures of Fusarium were isolated from bronchoalveolar lavage, blood, and sputum specimens.Treatments included amphotericin B, liposomal amphotericin B, caspofungin, voriconazole, and posaconazole, either alone or in combination. Lung involvement occurred in all patients with disseminated disease and it was associated with a poor outcome. The mortality rate in this group of patients was high (67%), and of those who survived, 1 patient was treated with a combination of amphotericin B and voriconazole, 1 patient with amphotericin B, and 1 patient with posaconazole. Recommended empirical treatment includes voriconazole, amphotericin B or liposomal amphotericin B first-line, and posaconazole for refractory disease. High-dose amphotericin B is recommended for treatment of most cases of fusariosis. The echinocandins (for example, caspofungin, micafungin, anidulafungin) are generally avoided because Fusarium species have intrinsic resistance to them. Treatment should ideally be based on the Fusarium isolate, susceptibility testing, and host-specific factors. Prognosis of fusariosis in the immunocompromised is directly related to a patient's immune status. Prevention of Fusarium infection is recommended with aerosolized amphotericin B deoxycholate, which also has activity against other important fungi.

Update on cutaneous manifestations of infectious diseases

Many emerging pathogens present in the skin and are of interest to dermatologists. Recent epidemics of measles, avian flu, and SARS demonstrated how an organism can rapidly spread worldwide because of airline travel. Travelers are often contagious before they are aware that they have the disease, contributing to the spread. This article reviews bacterial, mycobacterial, fungal, and viral pathogens important to dermatologists.

Antimycotic activity of 5'-prenylisoflavanones of the plant Geoffroea decorticans, against Aspergillus species

The antifungal activity of the ethanolic extract (EE), (3R)-5,7,2',3'-tetrahydroxy-4'-methoxy-5'-prenylisoflavanone (1) and (3R)-7-2'-3'-trihydroxy-4'-methoxy-5'-prenylisoflavanone (2) isolated from Geoffroea decorticans was evaluated against four different species of Aspergillus. Their effect was compared with that displayed by synthetic products. The antifungal activity was assayed by bioautography, hyphal radial growth, hyphal extent and microdilution in liquid medium. The percentage of hyphal radial growth inhibition produced by EE varied between 18.4+/-0.1 and 39.6+/-0.2 for Aspergillus nomius VSC23 and Aspergillus nomius 13137, respectively; and the same value for 1 and 2 were between 31.2+/-0.1-60.8+/-1.5 and 28.9+/-0.7-57.2+/-0.6 for Aspergillus flavus (IEV 018) and Aspergillus nomius 13137, respectively. The values of MIC/MFC determined for EE, 1 and 2 were compared with the actions of ascorbic and sorbic acids, and clotrimazole. The sequence of antifungal potency was clotrimazole>1>2>ascorbic acid>sorbic acid>EE. Consequently, EE as well as the purified substances from Geoffroea decorticans would be used as biopesticides against Aspergillus species. The cytotoxicity was evaluated.

Interactions between triazoles and amphotericin B in treatment of disseminated murine infection by Fusarium oxysporum

We have evaluated and compared the efficacies of high doses of amphotericin B (AMB; 3 mg/kg of body weight/day), voriconazole (60 mg/kg), and posaconazole (PSC; 100 mg/kg) alone and combined in a murine model of disseminated infection by Fusarium oxysporum. The combination of AMB with PSC showed the best results, prolonging the survival of mice and reducing their organ fungal loads. This combination might constitute a therapeutic option for those infections where monotherapies fail.

Imaging of pulmonary fusariosis in patients with hematologic malignancies

OBJECTIVE

The purpose of this study was to assess the radiographic features of pulmonary fusariosis, an increasingly encountered cause of severe opportunistic mold pneumonia.

CONCLUSION

Pulmonary fusariosis has radiographic manifestations that are suggestive of an angioinvasive mold. Nodules or masses were the most common findings at CT, seen in 82% of patients compared with only 45% on chest radiography. The halo sign was not seen. Chest radiographs showed nonspecific findings in 30% of patients, and findings were normal at presentation in 25%. All of the patients had underlying hematologic malignancies. Thirteen of the 20 patients studied (65%) died within 1 month of diagnosis of pulmonary fusariosis. Because early initiation of intense antifungal therapy offers the best chance for survival in pulmonary fusariosis, early CT and appropriate microbiologic investigation should be obtained in severely immunocompromised patients.

Fungal Infections

The incidence of invasive fungal infections has increased dramatically over the past two decades, mostly due to an increase in the number of immunocompromised patients.1–4 Patients who undergo chemotherapy for a variety of diseases, patients with organ transplants, and patients with the acquired immune deficiency syndrome have contributed most to the increase in fungal infections.5 The actual incidence of invasive fungal infections in transplant patients ranges from 15% to 25% in bone marrow transplant recipients to 5% to 42% in solid organ transplant recipients.6,7 The most frequently encountered are Aspergillus species, followed by Cryptococcus and Candida species. Fungal infections are also associated with a higher mortality than either bacterial or viral infections in these patient populations. This is because of the limited number of available therapies, dose-limiting toxicities of the antifungal drugs, fewer symptoms due to lack of inflammatory response, and the lack of sensitive tests to aid in the diagnosis of invasive fungal infections.1 A study of patients with fungal infections admitted to a university-affiliated hospital indicated that community-acquired infections are becoming a serious problem; 67% of the 140 patients had community-acquired fungal pneumonia.8

Purification and characterization of a lectin from endophytic fungus Fusarium solani having complex sugar specificity

A lectin from the mycelial extract of an endophytic strain of Fusarium solani was purified. Its hemagglutinating activity was inhibited by glycoproteins possessing N-linked as well as O-linked glycans. The thermodynamics and kinetics of binding of glycans and glycoproteins to F. solani lectin was studied using surface plasmon resonance. The lectin showed high affinity for asialofetuin, asialomucin, asialofibrinogen, and thyroglobulin; and comparatively low affinity for mucin, fetuin, fibrinogen, and holotransferrin. Glycoproteins showed several fold higher affinity than their corresponding glycans with significant contribution from enthalpy and positive entropy, suggesting the involvement of non-polar protein-protein interaction. Moreover, the higher affinity of the glycoproteins was due to their faster association rates and low activation energy.

Propolis from the northwest of Argentina as a source of antifungal principles

AIMS

To determine the antimycotic and cytotoxic activities of partially purified propolis extract on yeasts, xylophagous and phytopathogenic fungi. To compare these activities with pinocembrin and galangin isolated from this propolis and with the synthetic drugs ketoconazole and clortrimazole.

METHODS AND RESULTS

Ethanolic propolis extract was partially purified by cooling at -20 degrees C. Two of its components were isolated by HPLC and identified as pinocembrin and galangin. The antifungal activity was assayed by bioautography, hyphal radial growth, hyphal extent and microdilution in liquid medium. Cytotoxicity was studied with the lethality assay of Artemia salina. The obtained results were compared with the actions of ketoconazole and clortrimazole. The results showed that the antifungal potency of ketoconazole and clortrimazole is higher than pinocembrin, galangin and the partially purified propolis extract in this order. Otherwise, the cytotoxicity of the synthetic drugs is also the highest.

CONCLUSIONS

Partially purified propolis extract inhibits fungal growth. The comparison of its relative biocide potency and cytotoxicity with synthetic drugs and two components of this propolis (pinocembrin and galangin) showed that the propolis from 'El Siambón', Tucumán, Argentina, is a suitable source of antifungal products.

SIGNIFICANCE AND IMPACT OF THE STUDY

The partially purified propolis extract and its isolated compounds, pinocembrin and galangin, have the capacity of being used as antifungals without detriment to the equilibrium of agroecosystems. The impact of this study is that the preparation of agrochemicals with reduced economic costs using a partially purified preparation as the active principle is possible.

Emerging Fungi

The hyalohyphomycetes (especially Fusarium spp) have emerged as significant pathogens in severely immunocompromised patients. Human infections by Fusarium spp can be superficial or limited to single organs in otherwise healthy patients. Such infections are rare and tend to respond well to therapy. By contrast, disseminated fusarial hyalohyphomycosis affects the immunocompromised host and frequently is fatal. Successful outcome is determined by the degree of immunosuppression and the extent of the infection. These infections may be suspected clinically on the basis of a constellation of clinical and laboratory findings, which should lead to prompt therapy.

Posaconazole as Salvage Treatment for Invasive Fusariosis in Patients with Underlying Hematologic Malignancy and Other Conditions

BACKGROUND

Conventional amphotericin B-based antifungal therapy for invasive fusariosis in patients with a hematologic malignancy results in a > or = 70% failure rate. Posaconazole is a broad-spectrum antifungal agent with in vitro and in vivo activity against Fusarium species.

METHODS

In this retrospective analysis of patients from 3 open-label clinical trials, we evaluated posaconazole for the treatment of invasive fusariosis. Twenty-one patients with proven or probable invasive fusariosis who had disease refractory to or who were intolerant of standard antifungal therapy received oral posaconazole suspension (800 mg per day in divided doses) as salvage therapy.

RESULTS

Successful outcome occurred in 10 (48%) of all 21 patients. Among patients with leukemia who received posaconazole therapy for >3 days, the overall success rate was 50%; for patients who recovered from myelosuppression, the success rate was 67%, compared with 20% for those with persistent neutropenia.

CONCLUSION

These results suggest that posaconazole is useful for the treatment of invasive fusariosis.

Emerging fungal resistance

There has been an increase in systemic fungal infections over the past several decades, partially because of an increasing number of critically ill patients, surgical procedures, and immunosuppressive therapies, as well as the use of more invasive diagnostic and therapeutic medical procedures. Concomitant with this increase in infections has been the increase in azole-resistant Candida species and opportunistic molds with intrinsic resistance to many of the currently available antifungal agents. This review focuses on antifungal resistance, with emphasis on emerging resistance patterns and emerging fungi that are intrinsically resistant to antifungal agents.

Emerging fungal diseases: the importance of the host

More yeasts and molds are now recognized to cause more human disease than ever before. This development is not due to a change in the virulence of these fungi, but rather to changes in the human host. These changes include immunosuppression secondary to the pandemic of HIV, the use of life-saving advances in chemotherapy and organ transplantation, and the use of corticosteroids and other immunosuppressive agents to treat a variety of diseases. Fungi that were once considered common saprophytes are now recognized as potential pathogens in these patients. This situation necessitates better communication than ever between the clinician, pathologist, and clinical mycologist to ensure the prompt and accurate determination of the cause of fungal diseases.

Fusarium fungaemia in immunocompromised patients

Fusarium spp. cause infections only rarely in immunologically competent hosts, but disseminated infection may occur in severely immunocompromised patients. Symptoms of disseminated infection are persistent fever, despite broad-spectrum antibacterial and antifungal treatment, associated with skin lesions, most commonly on the extremities, in 60-80% of patients. A mortality rate of 50-75% has been reported for patients with disseminated fusariosis. Despite treatment failures, amphotericin B remains the preferred drug, in part because of lack of alternatives. Voriconazole is a promising new agent, but more clinical experience is required.

Human fusariosis

Fusarium species frequently implicated in human infections include F. solani, F. oxysporum and F. moniliforme. Among immunocompetent patients, tissue breakdown (as caused by trauma, severe burns or foreign body) is the risk factor for fusariosis. Infections include keratitis, onychomycosis and occasionally peritonitis and cellulitis. Treatment is usually successful and requires removal of the foreign body as well as antifungal therapy. Among immunocompromised patients, mainly patients with haematological malignancies, Fusarium spp. are the second most common pathogenic mould. Risk factors for disseminated fusariosis include severe immunosuppression (neutropenia, lymphopenia, graft-versus-host disease, corticosteroids), colonisation, tissue damage, and receipt of a graft from an HLA-mismatched or unrelated donor. Clinical presentation includes refractory fever (> 90%), skin lesions and sino-pulmonary infections ( approximately 75%). Type of skin lesions includes ecthyma-like, target, and multiple subcutaneous nodules. Skin lesions lead to diagnosis in > 50% of patients and precede fungemia by approximately 5 days. In contrast to disseminated aspergillosis, disseminated fusariosis can be diagnosed by blood cultures in 40% of patients. Histopathology reveals hyaline acute-branching septate hyphae similar to those found in aspergillosis. Mortality from fusarial infections in immunocompromised patients ranges from 50% to 80%. Host immune status is the single most important factor predicting outcome. Persistent neutropenia and corticosteroid therapy significantly affect survival. Optimal treatment has not been established. Anecdotal successes have been reported with various agents (high-dose amphotericin B, lipid-based amphotericin B formulations, itraconazole, voriconazole) and with cytokine-stimulated granulocyte transfusions. Preventing fusariosis relies on detection and treatment of cutaneous damage prior to commencing immunosuppression and decreasing environmental exposure to Fusaria (via air and water).

Infections due to emerging and uncommon medically important fungal pathogens

The emergence of less common but medically important fungal pathogens contributes to the rate of morbidity and mortality, especially in the increasingly expanding population of immunocompromised patients. These pathogens include septate filamentous fungi (e.g., Fusarium spp., Scedosporium spp., Trichoderma spp.), nonseptate Zygomycetes, the endemic dimorphic pathogen Penicillium marneffei, and non-Cryptococcus, non-Candida pathogenic yeast (e.g., Trichosporon spp.). The medical community is thus called upon to acquire an understanding of the microbiology, epidemiology and pathogenesis of these previously uncommon pathogens in order to become familiar with the options for prevention and treatment.

Voriconazole for serious fungal infections

Voriconazole is a new second generation triazole effective against a wide spectrum of fungal pathogens. A randomised, controlled trial has shown it to be superior to amphotericin B in invasive aspergillosis, and it is a potential alternative to amphotericin B in neutropenic sepsis and to fluconazole in oesophageal candidiasis. Early clinical reports and in vitro susceptibility data suggest that it may also be a valuable antifungal against fluconazole-resistant Candida species and certain emerging fungal pathogens, which cause infections that are often refractory to conventional therapies. There is limited evidence of azole cross-resistance of clinical importance. Voriconazole is available as intravenous and oral formulations and has excellent tissue penetration and a good safety profile, the main problems being transient visual impairment and hepatotoxicity in patients with liver disease. It is metabolised by cytochrome P-450 isoenzymes causing important drug interactions but, in contrast to amphotericin B, is safe in renal failure and rarely causes infusion-related reactions. This review outlines the pharmacology of voriconazole and focuses on its clinical applications and safety profile.

Toxic mold: phantom risk vs science

OBJECTIVE

To review the available literature on the subject of fungi (molds) and their potential impact on health and to segregate information that has scientific validity from information that is yet unproved and controversial.

DATA SOURCES

This review represents a synthesis of the available literature in this area with the authors' collective experience with many patients presenting with complaints of mold-related illness.

STUDY SELECTION

Pertinent scientific investigation on toxic mold issues and previously published reviews on this and related subjects that met the educational objectives were critically reviewed.

RESULTS

Indoor mold growth is variable, and its discovery in a building does not necessarily mean occupants have been exposed. Human response to fungal antigens may induce IgE or IgG antibodies that connote prior exposure but not necessarily a symptomatic state. Mold-related disease has been discussed in the framework of noncontroversial and controversial disorders.

CONCLUSIONS

When mold-related symptoms occur, they are likely the result of transient irritation, allergy, or infection. Building-related illness due to mycotoxicosis has never been proved in the medical literature. Prompt remediation of water-damaged material and infrastructure repair should be the primary response to fungal contamination in buildings.

Fungal biodiversity--as found in nasal mucus

The biodiversity of fungi isolated from the nasal mucus of patients suffering from chronic rhinosinusitis and from healthy persons was monitored over 28 months. Mucus samples were obtained by flushing the noses of patients with saline or by endoscopic sinus surgery. Fungi from mucus were cultivated on agar plates. Identification was performed microscopically and by polymerase chain reaction with subsequent sequencing of the ribosomal internal transcribed spacer region. Altogether, 619 strains of fungi were cultivated from 233 subjects. Eighty-one species were identified, with a maximum of nine different species per person. The most prevalent isolates belonged to the genera Penicillium, Aspergillus, Cladosporium, Alternaria and Aureobasidium. Whereas Aspergillus and Penicillium spp. occurred in more or less the same numbers throughout the year, Cladosporium spp., Alternaria spp. and Aureobasidium pullulans showed a significantly higher occurrence during late summer and early autumn.

Emerging and less common fungal pathogens

Less common and emerging fungal pathogens are often resistant to conventional antifungal therapy and may cause severe morbidity and mortality in immunocompromised hosts. Some Scedosporium species may be completely resistant to antifungal therapy. Hyaline septated filamentous fungi, such as Fusarium species, Acremonium species, Paecilomyces species, and Trichoderma species, are increasingly reported as causing invasive mycoses refractory to amphotericin B therapy. Dematiaceous septated filamentous fungi, such as Bipolaris species may cause pneumonia, sinusitis, and CNS infections that are unresponsive to current medical interventions. Trichosporon spp are resistant to the fungicidal effects of amphotericin B. An increasing number of different members of the class Zygomycetes are reported as causing lethal infections, despite aggressive medical and surgical interventions. Infections due to these and other less common and emergent fungal pathogens will likely continue to develop in the settings of selective anti-fungal pressure, permissive environmental conditions, and an expanding population of immunocompromised hosts.

Cutaneous infection by Fusarium species in healthy and immunocompromised hosts: implications for diagnosis and management

Infections by Fusarium species frequently involve the skin, either as the primary or the metastatic site. To better understand the pathophysiology of these infections, 43 new patients with fusariosis were evaluated, and the literature was reviewed. A total of 259 patients (232 immunocompromised and 27 immunocompetent) were identified. Skin involvement was present in 70% of patients, particularly in immunocompromised patients (72% vs. 52%; P=.03). In immunocompetent patients, cutaneous infections were characterized by preceding skin breakdown, localized involvement, slow pace of progression, and good response to therapy. In contrast, skin involvement in immunocompromised patients was only occasionally preceded by skin breakdown and typically was presented as rapidly progressive disseminated lesions at various stages of evolution. Metastatic skin lesions were associated with fungemia, neutropenia, and death. Skin was the single source of diagnosis for the majority of immunocompromised and immunocompetent patients. Recommendations for the prevention of fatal fusariosis originating from skin are presented.

Optimal testing conditions for determining MICs and minimum fungicidal concentrations of new and established antifungal agents for uncommon molds: NCCLS collaborative study

This collaborative three-center study evaluated NCCLS M38-A document testing conditions and other testing conditions for the antifungal susceptibility testing of 35 isolates of Aspergillus nidulans, A. terreus, Bipolaris hawaiiensis, B. spicifera, Cladophialophora bantiana, Dactylaria constricta, Fusarium solani, Paecilomyces lilacinus, Scedosporium prolificans, Trichoderma longibrachiatum, and Wangiella dermatitidis for itraconazole, three new triazoles (voriconazole, posaconazole, and ravuconazole), and amphotericin B. MICs and minimum fungicidal concentrations (MFCs) were determined in each center by using four media (standard RPMI-1640 [RPMI], RPMI with 2% dextrose [RPMI-2%], antibiotic medium 3 [M3], and M3 with 2% dextrose [M3-2%]) and two criteria of MIC determination (complete growth inhibition [MICs-0] and prominent growth inhibition [MICs-2]) at 24, 48 and 72 h. MFCs were defined as the lowest drug concentrations that yielded <3 colonies (approximately 99 to 99.5% killing activity). The reproducibility (within three wells) was higher among MICs-0 (93 to 99%) with either RPMI or M3 media than among all MICs-2 (86 to 95%) for the five agents at 48 to 72 h. The agreement for MFCs was lower (86 to 94%). Based on interlaboratory agreement, the optimal testing conditions were RPMI broth, 48 to 72 h of incubation and 100% growth inhibition (MIC-0); MFCs can be obtained after MIC determination with the above optimal testing parameters. These results warrant consideration for inclusion in the future version of the NCCLS M38 document. However, the role of these in vitro values as predictors of clinical outcome remains to be established in clinical trials.

Fusarium dimerum as a cause of human eye infections

Fusarium dimerum, typically a soil fungus, was isolated from an adult male suffering from a corneal ulcer following an injury to the eye. This fungus has not been described to cause human infections in South Africa and has not been recorded from soil, plant or organic material in this country. The macro- and microscopic characteristics of the isolate were found to be indistinguishable from described strains. Its authenticity was confirmed by comparing it to other human isolates from the eye obtained in the USA, thus rendering this the first report of F. dimerum from an eye infection in a human in South Africa.

Necrotizing periorbital Fusarium infection--an emerging pathogen in immunocompetent individuals

Fungal infections of the skin and deeper tissues of the periorbital region are quite rare. We report a case of a localized, deep periorbital necrotizing Fusarium infection in an otherwise healthy, elderly lady. Since the clinical features and histopathological findings of Fusarium infection are by no means characteristic, the definitive diagnosis was achieved with the help of microbiological examination of cultured organisms. A combined medical and surgical therapy led to adequate control of infection. To conclude, localized, deep periorbital necrotizing soft tissue infection by Fusarium in an immunocompetent lady is not reported in literature. One should have a high index of suspicion for emerging fungal pathogens in the differential diagnosis of necrotizing orbital or adnexal conditions, even in an immunocompetent patient. The histologic findings of septate, branching hyphae and vascular invasion cannot distinguish Fusarium species from various other moulds such as Aspergillus species; microbiologic studies are essential for confirming the diagnosis.

Uncommon opportunistic fungi: new nosocomial threats

During the past two decades opportunistic fungal infections have emerged as important causes of morbidity and mortality in patients with severe underlying illnesses and compromised host defenses. While Aspergillus and Candida spp. collectively account for the majority of these infections, recent epidemiological trends indicate a shift towards infections by Aspergillus spp., nonalbicans Candida spp., as well as previously uncommon opportunistic fungi. Apart from an expanding number of different Zygomycetes, previously uncommon hyaline filamentous fungi (such as Fusarium species, Acremonium species, Paecilomyces species, Pseudallescheria boydii, and Scedosporium prolificans), dematiaceous filamentous fungi (such as Bipolaris species, Cladophialophora bantiana, Dactylaria gallopava, Exophiala species, and Alternaria species) and yeast-like pathogens (such as Trichosporon species, Blastoschizomyces capitatus, Malassezia species, Rhodotorula rubra and others) are increasingly encountered as causing life threatening invasive infections that are often refractory to conventional therapies. On the basis of past and current trends, the spectrum of fungal pathogens will continue to evolve in the settings of an expanding population of immunocompromised hosts, selective antifungal pressures, and shifting conditions in hospitals and the environment. An expanded and refined drug arsenal, further elucidation of pathogenesis and resistance mechanisms, establishment of in vitro/in vivo correlations, incorporation of pharmacodynamics, combination- and immunotherapies offer hope for substantial progress in prevention and treatment.

In vitro antifungal activities of voriconazole and reference agents as determined by NCCLS methods: review of the literature

Voriconazole (VfendTM) is a new triazole that currently is undergoing phase III clinical trials. This review summarizes the published data obtained by NCCLS methods on the in vitro antifungal activity of voriconazole in comparison to itraconazole, amphotericin B, fluconazole, ketoconazole and flucytosine. Voriconazole had fungistatic activity against most yeasts and yeastlike species (minimum inhibitory concentrations [MICs] < 2 microg/ml) that was similar or superior to those of fluconazole, amphotericin B, and itraconazole. Against Candida glabrata and C. krusei, voriconazole MIC ranges were 0.03 to 8 and 0.01 to > 4 microg/ml, respectively. For four of the six Aspergillus spp. evaluated, voriconazole MICs (< 0.03 to 2 microg/ml) were lower than amphotericin B (0.25 to 4 microg/ml) and similar to itraconazole MICs. Voriconazole fungistatic activity against Fusarium spp. has been variable. Against E oxysporum and F. solani, most studies showed MICs ranging from 0.25 to 8 microg/ml. Voriconazole had excellent fungistatic activity against five of the six species of dimorphic fungi evaluated (MIC90s < 1.0 microg/ml). The exception was Sporothrix schenckii (MIC90s and geometric mean MICs > or = 8 microg/ml). Only amphotericin B had good fungistatic activity against the Zygomycetes species (voriconazole MICs ranged from 2 to > 32 microg/ml). Voriconazole showed excellent in vitro activity (MICs < 0.03 to 1.0 microg/ml) against most of the 50 species of dematiaceous fungi tested, but the activity of all the agents was poor against most isolates of Scedosporium prolificans and Phaeoacremonium parasiticum (Phialophora parasitica). Voriconazole had fungicidal activity against most Aspergillus spp., B. dermatitidis, and some dematiaceous fungi. In vitro/in vivo correlations should aid in the interpretation of these results.

Comparison of the E-test with the NCCLS M38-P method for antifungal susceptibility testing of common and emerging pathogenic filamentous fungi

The National Committee for Clinical Laboratory Standards (NCCLS) M38-P method describes standard parameters for testing the fungistatic antifungal activities (MICs) of established agents against filamentous fungi (molds). The present study evaluated the in vitro fungistatic activities of itraconazole and amphotericin B by the E-test and the NCCLS M38-P microdilution method against 186 common and emerging pathogenic molds (123 isolates of Aspergillus spp. [five species], 16 isolates of Fusarium spp. [two species], 4 Paecilomyces lilacinus isolates, 5 Rhizopus arrhizus isolates, 15 Scedosporium spp., 18 dematiaceous fungi, and 5 Trichoderma longibrachiatum isolates). The agreement between the methods for amphotericin B MICs ranged from 70% for Fusarium solani to > or =90% for most of the other species after the first reading; agreement was dependent on both the incubation time and the species being evaluated. Major discrepancies between the amphotericin B MICs determined by the E-test and the NCCLS M38-P method were demonstrated for three of the five species of Aspergillus tested and the two species of Fusarium tested. This discrepancy was more marked after 48 h of incubation; the geometric mean MICs determined by the E-test increased between 24 and 48 h from between 1.39 and 3.3 microg/ml to between 5.2 and >8 microg/ml for Aspergillus flavus, Aspergillus fumigatus, and Aspergillus nidulans. The agreement between the itraconazole MICs determined by the E-test and the NCCLS M38-P method ranged from 83.3% for A. nidulans to > or =90% for all the other species tested; the overall agreement was higher (92.7%) than that for amphotericin B (87.9%). The agreement was less dependent on the incubation time. Clinical trials need to be conducted to establish the role of the results of either the E-test or the NCCLS M38-P method in vitro for molds with the two agents as predictors of clinical outcome.

In vitro fungicidal activities of voriconazole, itraconazole, and amphotericin B against opportunistic moniliaceous and dematiaceous fungi

The NCCLS proposed standard M38-P describes standard parameters for testing the fungistatic antifungal activities (MICs) of established agents against filamentous fungi (molds); however, standard conditions are not available for testing their fungicidal activities (minimum fungicidal or lethal concentrations [MFCs]). This study evaluated the in vitro fungistatic and fungicidal activities of voriconazole, itraconazole, and amphotericin B against 260 common and emerging molds (174 Aspergillus sp. isolates [five species], 23 Fusarium sp. isolates [three species], 6 Paecilomyces lilacinus isolates, 6 Rhizopus arrhizus isolates, 23 Scedosporium sp. isolates, 23 dematiaceous fungi, and 5 Trichoderma longibrachiatum isolates). MICs were determined by following the NCCLS M38-P broth microdilution method. MFCs were the lowest drug dilutions that resulted in fewer than three colonies. Voriconazole showed similar or better fungicidal activity (MFC at which 90% of isolates tested are killed [MFC(90)], 1 to 2 microg/ml) than the reference agents for Aspergillus spp. with the exception of Aspergillus terreus (MFC(90) of voriconazole and amphotericin B, >8 microg/ml). The voriconazole geometric mean (G mean) MFC for Scedosporium apiospermum was lower (2.52 microg/ml) than those of the other two agents (5.75 to 7.5 microg/ml). In contrast, amphotericin B and itraconazole G mean MFCs for R. arrhizus were 2.1 to 2.2 microg/ml, but that for voriconazole was >8 microg/ml. Little or no fungicidal activity was shown for Fusarium spp. (2 to >8 microg/ml) and Scedosporium prolificans (>8 microg/ml) by the three agents, but voriconazole had some activity against P. lilacinus and T. longibrachiatum (G mean MFCs, 1.8 and 4 microg/ml, respectively). The fungicidal activity of the three agents was similar (G mean MFC, 1.83 to 2.36 microg/ml) for the dematiaceous fungi with the exception of the azole MFCs (>8 microg/ml) for some Bipolaris spicifera and Dactylaria constricta var. gallopava. These data extend and corroborate the available fungicidal results for the three agents. The role of the MFC as a predictor of clinical outcome needs to be established in clinical trials by following standardized testing conditions for determination of these in vitro values.