Invasive Fusariosis in Patients with Hematologic Diseases

The pathobiology of human fungal infections

Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.

Risk of fungal exposure in the homes of patients with hematologic malignancies

BACKGROUND

Patients with hematological malignancies are at a high risk of developing invasive fungal infections (IFI) because they undergo several cycles of treatment leading to episodes of neutropenia. In addition, they alternate between hospital stays and periods spent at home. Thus, when an IFI is diagnosed during their hospital stays, it is highly challenging to identify the origin of the fungal contamination. The objective of this study was to analyze at home fungal exposure of 20 patients with leukemia by taking air and water samples in their living residence.

METHODS

Air was sampled in 3 rooms of each home with a portable air system impactor. Tap water was collected at 3 water distribution points of each home. For positive samples, fungi were identified by mass spectrometry or on the basis of their morphological features.

RESULTS

85 % of homes revealed the presence in air of Aspergillus spp. and those belonging to the section Fumigati presented the highest concentrations and the greatest frequency of isolation. Concerning mucorales, Rhizopus spp. and Mucor spp. were isolated in air of 20 % and 5 % of dwellings, respectively. In 4 homes, more than 70 % of the fungal species identified in air were potential opportunists; these were mainly Aspergillus spp. with concentrations greater than 20 cfu/m3. The water samples revealed the presence of Fusarium in 3 dwellings, with concentrations up to 80 cfu/L. Finally, for one patient, fungal species isolated during a period of hospitalization were phenotypically similar to those isolated in samples taken at home. For a second patient, a PCR Mucorale was positive on a sample of bronchoalveolar fluid while air samples taken at his home also revealed also the presence of mucorales.

CONCLUSION

The presence of opportunistic fungal species in the air of all the explored homes suggests the need for strengthened preventive measures in the home of immunocompromised patients. It would be interesting to compare the fungi isolated (from patients and from their environment) by genotyping studies aimed at specifying the correspondence existing between fungal species present in the patients' homes and those responsible for IFI in the same patients.

Portilla C, Valenzuela R, Motta F, Motta FA, de Almeida Junior JN, Santolaya ME, Lopes Colombo A. Landscape of Invasive Fusariosis in Pediatric Cancer Patients: Results of a Multicenter Observational Study From Latin America

Invasive fusariosis (IF) is a life-threatening opportunistic infection that affects vulnerable hosts. We conducted a multicenter and multinational retrospective study to characterize the natural history and clinical management of IF in pediatric cancer patients. We selected patients <18 years old who were sequentially hospitalized in 10 Latin American medical centers with a diagnosis of IF between 2002 and 2021. Data were collected using an electronic case report form complemented by a dictionary of terms. We assessed mortality rates at 30, 60, and 90 days. We collected data from 60 episodes of IF (median age, 9.8 years) that were mostly documented in patients with hematologic cancer (70%). Other risk conditions found were lymphopenia (80%), neutropenia (76.7%), and corticosteroid exposure (63.3%). IF was disseminated in 55.6% of patients. Skin lesions was present in 58.3% of our patients, followed by pulmonary involvement in 55%, sinusitis in 21.7%, bone/joint involvement in 6.7% and 1 case each of endocarditis and brain abscess. Positive blood and skin biopsy cultures were detected in 60% and 48.3% of cases, respectively. Fusarium solani complex was the most commonly identified agent (66.6%). The majority of patients received monotherapy within the first 72 hours (71.6%), either with voriconazole or amphotericin B formulation. The mortality rates at 30, 60, and 90 days were 35%, 41.6%, and 45%, respectively. An important factor affecting mortality rates appears to be disseminated disease. The high percentage of patients with fungal involvement in multiple organs and systems highlights the need for extensive workup for additional sites of infection in severely immunocompromised children.

Lung infections due to emerging fungal pathogens

PURPOSE OF REVIEW

This review highlights the epidemiology, pathogenesis and clinical management of pulmonary infections caused by emerging fungal organisms.

RECENT FINDINGS

Emerging fungal infections have arisen as a result of population and environmental changes. An enlarging pool of immunocompromised hosts on triazole antifungal prophylaxis has led to an increased incidence of non- Aspergillus molds, such as Fusarium , Scedosporium and Lomentospora spp. Advances in diagnostic capabilities led to the identification of the Emergomyces genus and non- dermatitidis Blastomyces species, which have a significant disease burden in Africa and the Middle East. Climate change has contributed to changing the distribution of previously confined endemic mycoses, like coccidioidomycosis and talaromycosis. These emerging organisms pose important diagnostic and therapeutic challenges.

SUMMARY

Newly recognized pathogenic fungi and established endemic mycoses with expanding geographic boundaries have become important agents of pulmonary disease. There is a dearth of clinical evidence on the appropriate management of these infections.

Invasive fungal rhinosinusitis by Fusarium proliferatum/annulatum in a patient with acute myeloid leukemia: A case report and review of the literature

Antifungal prophylaxis with a mold-effective agent has led to a substantial decrease in invasive infections caused by Aspergillus spp. in the management of patients with acute myeloid leukemia undergoing induction chemotherapy. However, difficult-to-treat infections caused by other molds, such as Fusarium, Lomentospora, and Scedosporium species may still complicate the neutropenic period. Here, we present a case of a 23-year-old woman with acute myeloid leukemia who developed a breakthrough invasive fungal rhinosinusitis caused by Fusarium proliferatum/annulatum on posaconazole prophylaxis. The infection was diagnosed using clinical, microbiological, and radiological criteria and the isolate was identified using Matrix Assisted Lazer Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and sequencing. We searched Pubmed with "Fusarium proliferatum", "Fusarium annulatum", "immunosuppression AND fusariosis", "rhinosinusitis AND Fusarium proliferatum" and summarized the English literature for similar rhinosinusitis cases infected with the same pathogen.

First report of fatal fungemia due Fusarium oxysporum in a patient with COVID-19 in Ecuador

Filamentous fungal infections are an important cause of systemic infections in immunocompromised patients. Fusarium genus members potentially cause disseminated infections, especially in patients with catheters, due to the ability to adhere to these devices. We describe a case of fatal fungemia due to Fusarium oxysporum in a patient with COVID-19 in Ecuador. The genus identification was carried out with conventional techniques and species identification by molecular and phylogenetic techniques through sequencing of the ITS region.

Multicenter Retrospective Study of Invasive Fusariosis in Intensive Care Units, France

Invasive fusariosis can be life-threatening, especially in immunocompromised patients who require intensive care unit (ICU) admission. We conducted a multicenter retrospective study to describe clinical and biologic characteristics, patient outcomes, and factors associated with death and response to antifungal therapy. We identified 55 patients with invasive fusariosis from 16 ICUs in France during 2002----2020. The mortality rate was high (56%). Fusariosis-related pneumonia occurred in 76% of patients, often leading to acute respiratory failure. Factors associated with death included elevated sequential organ failure assessment score at ICU admission or history of allogeneic hematopoietic stem cell transplantation or hematologic malignancies. Neither voriconazole treatment nor disseminated fusariosis were strongly associated with response to therapy. Invasive fusariosis can lead to multiorgan failure and is associated with high mortality rates in ICUs. Clinicians should closely monitor ICU patients with a history of hematologic malignancies or stem cell transplantation because of higher risk for death.

Clinical spectrum of fusariosis from a tertiary care center in India- a retrospective study

Background and Objectives

Fusarium spp. is an emerging pathogen that presents with varied clinical presentations but there are very few studies from India that elaborate on the spectrum of infection caused by the fungus. Hence, the present study was conducted in our institute to understand the clinical spectrum of fusariosis.

Materials and Methods

The present study was a retrospective study conducted at a tertiary care institute, in Hyderabad, Telangana, India for four years from January 2018 to December 2022. All the patients with clinically significant isolation of Fusarium spp. from various samples were included in the study.

Results

There were 25 cases of fusariosis diagnosed during the study period. Fusarium was isolated predominantly from debrided tissue following road traffic accidents in 12/25 (84%) of the cases, nails in 3/25 (12%) and superficial leg ulcer in 1/25 (4%) of the cases. Speciation was done for four patients. Three were Fusarium incarnatum and one was Fusarium solani. The patients were treated surgically and with/without antifungal therapy and were discharged in a stable condition.

Conclusion

Traumatic injuries were the major cause of infections in the present study. As Fusarium is a virulent and highly resistant pathogen, an early suspicion and an appropriate diagnosis would lead to a better outcome in these patients.

Fusariosis in patients with hematological malignancies: Two case reports

Immunosuppressed patients with hematological malignancies are at risk for invasive fungal infections (IFI), including infections with Fusarium species (spp.), which are increasingly reported. Particularly at risk are patients with acute myeloid leukemia (AML) treated with high-dose cytarabine as remission-induction therapy. Whether cytarabine increases the risk of IFI in comparison to other chemotherapy remains not fully determined. Additionally, no clear correlation between the in vitro established minimal inhibitory concentrations (MICs) of antifungal agents and clinical outcome has been established for fusariosis. To increase awareness and knowledge of invasive fusariosis, we report two cases of Fusarium spp. infections in neutropenic patients following treatment with cytarabine for AML. Despite high MICs for azoles both patients were treated with an azole in combination with liposomal amphotericin B. The combination therapy was successful in one patient, however the other patient did not survive the disseminated Fusarium infection.

An unusual presentation of invasive Fusarium aortitis in a patient who is immunocompromised: A case report

Fusarium (F.) species are ubiquitous filamentous fungi that may cause various opportunistic infections, especially in patients who are immunocompromised. A rare manifestation of disseminated fusariosis affects the aortic valve and results in invasive aortitis, which poses a significant challenge for clinicians in diagnosis and treatment. Here, we report a case of a patient, aged 54 years, who is immunocompromised, presenting initially with Fusarium keratitis and chorioretinitis in both eyes and a new endovascular aortic mass. Positron emission tomography/computed tomography was performed, suggesting aortitis. Transoesophageal echocardiography and electrocardiogram-guided computed tomography-angiography confirmed a large intraluminal mass in the ascending aorta. The aortic mass and a part of the ascending aorta were resected surgically, and a filamentous fungus with the microscopic features of the genus Fusarium was isolated and later identified molecularly as F. petroliphilum. The course of the treatment was complicated by perioperative cerebral embolization and mesenteric ischemia. These complications could be attributed to a preoperatively existing occlusion of the superior and inferior mesenteric artery and a subtotal stenosis of the celiac trunk. This case report describes a rare manifestation of disseminated fusariosis, frequently characterized by protracted clinical courses with poor prognosis. Fusariosis may manifest at different sites at different times or persist as a long-lasting disease with reactivation. This case highlights the importance of the interdisciplinary approach for effectively treating invasive mycoses.

Intestinal Candida albicans overgrowth in IgA deficiency

BACKGROUND

Secretory IgA interacts with commensal bacteria, but its impact on human mycobiota ecology has not been widely explored. In particular, whether human IgA-deficiency is associated with gut fungal dysbiosis remains unknown.

OBJECTIVES

Our goal was to study the impact of IgA on gut mycobiota ecology.

METHODS

The Fungi-Flow method was used to characterize fecal, systemic, and maternal IgA, IgM, and IgG responses against 14 representative fungal strains (yeast/spores or hyphae forms) in healthy donors (HDs) (n = 34, 31, and 20, respectively) and to also compare gut mycobiota opsonization by secretory antibodies in HDs (n = 28) and patients with selective IgA deficiency (SIgAd) (n = 12). Stool mycobiota composition was determined by internal transcribed spacer gene sequencing in HDs (n = 23) and patients with SIgAd (n = 17). Circulating CD4+ T-cell cytokine secretion profiles were determined by intracellular staining. The impact of secretory IgA, purified from breast milk (n = 9), on Candidaalbicans growth and intestinal Caco-2 cell invasion was tested in vitro.

RESULTS

Homeostatic IgA binds commensal fungi with a body fluid-selective pattern of recognition. In patients with SIgAd, fungal gut ecology is preserved by compensatory IgM binding to commensal fungi. Gut Calbicans overgrowth nevertheless occurs in this condition but only in clinically symptomatic patients with decreased TH17/TH22 T-cell responses. Indeed, secretory IgA can reduce in vitro budding and invasion of intestinal cells by Calbicans and therefore exert control on this pathobiont.

CONCLUSION

IgA has a selective impact on Calbicans ecology to preserve fungal-host mutualism.

Performance of the beta-glucan test for the diagnosis of invasive fusariosis and scedosporiosis: a meta-analysis

The (1→3)-β-D-glucan (BDG) is a component of the fungal cell wall that can be detected in serum and used as an adjunctive tool for the diagnosis of invasive mold infections (IMI) in patients with hematologic cancer or other immunosuppressive conditions. However, its use is limited by modest sensitivity/specificity, inability to differentiate between fungal pathogens, and lack of detection of mucormycosis. Data about BDG performance for other relevant IMI, such as invasive fusariosis (IF) and invasive scedosporiosis/lomentosporiosis (IS) are scarce. The objective of this study was to assess the sensitivity of BDG for the diagnosis of IF and IS through systematic literature review and meta-analysis. Immunosuppressed patients diagnosed with proven or probable IF and IS, with interpretable BDG data were eligible. A total of 73 IF and 27 IS cases were included. The sensitivity of BDG for IF and IS diagnosis was 76.7% and 81.5%, respectively. In comparison, the sensitivity of serum galactomannan for IF was 27%. Importantly, BDG positivity preceded the diagnosis by conventional methods (culture or histopathology) in 73% and 94% of IF and IS cases, respectively. Specificity was not assessed because of lacking data. In conclusion, BDG testing may be useful in patients with suspected IF or IS. Combining BDG and galactomannan testing may also help differentiating between the different types of IMI.

Fusarium spp. in Human Disease: Exploring the Boundaries between Commensalism and Pathogenesis

Fusarium is a large fungal genus that is widely distributed in the environment, mostly known for its plant pathogenicity. Rarely, it is involved in human pathology, where the type of infection caused is highly dependent upon the portal of entry and the immune status of the host. The study at hand aims to summarize routine methods used in diagnosing such infections as well as more advanced molecular diagnostic methods, techniques that can play a huge role in differentiating between colonization and infection when trying to decide the therapeutic outcome. Consequently, to further support our findings, two different strains (one isolated from corneal scrapings and one isolated from purulent discharge) were analyzed in a clinical context and thoroughly tested using classical and modern diagnostic methods: identification by macroscopical and microscopical examinations of the culture and mass spectrometry, completed by molecular methods such as PCR for trichothecene and ERIC-PCR for genetic fingerprinting. Isolation of a clinically relevant Fusarium spp. from a sample still remains a diagnostic challenge for both the clinician and the microbiologist, because differentiating between colonization and infection is very strenuous, but can make a difference in the treatment that is administered to the patient.

Invasive fusariosis in acute leukaemia patients-An outbreak in the haematology ward

Fusarium, a common fungus, emerges as a pathogen in severely immunocompromised patients. We present a series of patients who developed invasive fusariosis (IF) during admission to an acute leukaemia ward: an outbreak of 12 cases in June and July 2018, followed by four sporadic cases until 2021. No case was reported earlier. All patients were clustered in the same location with indoor air and water installations found to be contaminated with Fusarium spp. thus a nosocomial outbreak was assumed. Following the water installation replacement, the number of Fusarium cases dramatically dropped to one or two isolated instances per year in the same location. All 16 patients had acute leukaemia and developed IF during severe neutropenia following induction therapy. IF diagnosis was based on positive blood cultures (14 patients) and/or on tissue biopsies (3 patients). The median time from admission to the IF onset was 20 days, and from the first day of severe neutropenia (≤500/mm3) was 11.5 days. All patients were febrile, eight had moderate-to-severe myalgias, eight had respiratory involvements: lung lesions and/or sinusitis and seven had characteristic skin lesions. Follow-up: 12 out of 16 (75%) were alive on Day 90; nine out of 15 (60%) were alive on Month 6. All with intractable neutropenia died. In severely neutropenic febrile patients, the triad of respiratory involvement/skin lesions/severe myalgia may suggest Fusarium aetiology. The ability to recover from neutropenia is critical to surmount IF. The indoor environment in immunocompromised dedicated settings must be constantly controlled.

Clinical Manifestations of Human Exposure to Fungi

Biological particles, along with inorganic gaseous and particulate pollutants, constitute an ever-present component of the atmosphere and surfaces. Among these particles are fungal species colonizing almost all ecosystems, including the human body. Although inoffensive to most people, fungi can be responsible for several health problems, such as allergic fungal diseases and fungal infections. Worldwide fungal disease incidence is increasing, with new emerging fungal diseases appearing yearly. Reasons for this increase are the expansion of life expectancy, the number of immunocompromised patients (immunosuppressive treatments for transplantation, autoimmune diseases, and immunodeficiency diseases), the number of uncontrolled underlying conditions (e.g., diabetes mellitus), and the misusage of medication (e.g., corticosteroids and broad-spectrum antibiotics). Managing fungal diseases is challenging; only four classes of antifungal drugs are available, resistance to these drugs is increasing, and no vaccines have been approved. The present work reviews the implications of fungal particles in human health from allergic diseases (i.e., allergic bronchopulmonary aspergillosis, severe asthma with fungal sensitization, thunderstorm asthma, allergic fungal rhinosinusitis, and occupational lung diseases) to infections (i.e., superficial, subcutaneous, and systemic infections). Topics such as the etiological agent, risk factors, clinical manifestations, diagnosis, and treatment will be revised to improve the knowledge of this growing health concern.

In vitro antifungal susceptibility profile of Iranian Fusarium isolates: Emphasising on the potent inhibitory effect of efinaconazole compared to other drugs

BACKGROUND

Fusarium species are opportunistic human pathogens that remarkably cause fungal infections ranging from superficial to fatal invasive disseminated infections. Fusarium species are notoriously resistant to the majority of antifungal agents.

OBJECTIVES

Therefore, detailed studies regarding in vitro susceptibility are required and may lead to a better prognosis of severe infections.

METHODS

We evaluated 25 antifungal drugs in vitro against 282 clinical and environmental Fusarium isolates.

RESULTS

Fusarium species demonstrated high MICs/MECs values to the most commonly used antifungal drugs in clinical practice. The geometric mean (GM) MICs for luliconazole (0.004 μg/ml) and lanoconazole (0.012 μg/ml) were the lowest, followed by efinaconazole (0.98 μg/ml) and amphotericin B (1.04 μg/ml).

CONCLUSIONS

Efinaconazole, a novel triazole, may be a promising candidate for the treatment of superficial Fusarium infections. Furthermore, the development of systemic formulations of these drugs as well as further in vitro and in vivo investigations could aid in the treatment of systemic fusariosis.

Detection of circulating DNA for the diagnosis of invasive fusariosis: retrospective analysis of 15 proven cases

Fusarium spp. are plant pathogens and opportunistic pathogens in severely immunocompromised (hematological malignancy, neutropenia, solid organ transplantation, …) and severely burned patients. Invasive fusariosis often disseminates and mortality remains high partly due to delayed diagnosis in the absence of a positive culture. The aim of our study is to design a qPCR assay and evaluate the detection of Fusarium spp. DNA for early diagnosis of invasive infection. A qPCR assay was designed and optimized to identify all Fusarium species complex and secondarily evaluated on patient samples. A total of 81 blood samples from 15 patients diagnosed with proven invasive fusariosis from 9 centers in France were retrospectively tested. Circulating DNA was detected in 14 patients out of 15 (sensitivity of 93% [IC95, 70.1-99.7]). Detection was possible up to 18 days (median 6 days) before the diagnosis was confirmed by positive blood culture or biopsy. By comparison serum galactomannan and ß-D-glucan were positive in 7.1 and 58.3% of patients respectively. qPCR was negative for all patients with other invasive fungal diseases (IFD) tested (n = 12) and IFD-free control patients (n = 40). No cross-reactions were detected using DNA extracted from 81 other opportunistic fungi. We developed and validated a pan-Fusarium qPCR assay in serum/plasma with high sensitivity, specificity and reproducibility that could facilitates early diagnosis and treatment monitoring of invasive fusariosis.

Invasive Fusariosis in Pediatric Hematology/Oncology and Stem Cell Transplant Patients: A Report from the Israeli Society of Pediatric Hematology-Oncology

Invasive Fusarium species infections in immunocompromised patients occur predominantly in those with hematological malignancies. Survival rates of 20−40% were reported in adults, but data in children are limited. Our retrospective, nationwide multicenter study of invasive fusariosis in pediatric hematology/oncology and stem cell transplant (SCT) patients identified twenty-two cases. Underlying conditions included hematological malignancies (n = 16; 73%), solid tumors (n = 2), and non-malignant hematological conditions (n = 4). Nineteen patients (86%) were neutropenic, nine (41%) were SCT recipients, and seven (32%) received corticosteroids. Sixteen patients (73%) had disseminated fusariosis, five had local infection, and one had isolated fungemia. Fifteen patients (68%) had skin involvement and eight (36%) had a bloodstream infection. Four patients (18%) presented with osteoarticular involvement and four with pulmonary involvement. Nineteen patients (86%) received combination antifungal therapy upfront and three (14%) received single-agent treatment. Ninety-day probability of survival was 77%: four of the five deaths were attributed to fusariosis, all in patients with relapsed/refractory acute leukemias. Ninety-day probability of survival for patients with relapsed/refractory underlying malignancy was 33% vs. 94% in others (p < 0.001). Survival rates in this largest pediatric population-based study were strikingly higher than those reported in adults, demonstrating that invasive fusariosis is a life-threatening but salvageable condition in immunosuppressed children.