The expanding use of matrix-assisted laser desorption/ionization-time of flight mass spectroscopy in the diagnosis of patients with mycotic diseases

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.

Practical issues related to non-Aspergillus invasive mold infections

Infection by non-Aspergillus molds has been increasingly reported. The management of such infections is challenging both for diagnosis and treatment, including the need of well-trained mycologists to properly identify rare fungi, difficulties in distinguishing between contamination, colonization and infection, the lack of randomized studies comparing different drugs or regimens, poor activity of available antifungal agents, lack of correlation between in vitro antifungal susceptibility tests and clinical outcome, and poor prognosis. Mucormycosis and fusariosis are the most frequent non-Aspergillus mold infections. Mucormycosis occurs more frequently in four major groups of patients: solid organ transplant recipients, patients with hematologic malignancies receiving chemotherapy or hematopoietic cell transplantation, diabetic patients, and immunocompetent individuals who suffer various types of skin and soft tissue trauma. Invasive fusariosis occurs almost exclusively in patients with hematologic malignancies. In this review we discuss practical issues related to the management of these and other non-Aspergillus mold infections.

Fungemia due to rare non-Candida yeasts between 2018 and 2021 in a Greek tertiary care university hospital

INTRODUCTION

Non-Candida yeasts, although rare, are increasingly encountered and recognized as a growing threat.

METHODS

Cases of bloodstream infections (BSIs) due to non-Candida yeasts (NCYs) during the last four years (2018-2021) are presented.

RESULTS

During the study period, 16 cases caused by non-Candida yeasts out of 400 cases of yeast BSIs were recorded, corresponding to an incidence of 4%. Yeasts that were isolated included Cryptococcus spp (4 isolates-25%), Rhodotorula mucilaginosa (2 isolates-12.5%), Trichosporon asahii (7 isolates-43.75%) and Saccharomyces cerevisiae (3 isolates-18.75%). Predisposing factors involved mostly hematological malignancies, long term hospitalization or major surgical interventions. Most isolates, 15 out of 16 were susceptible to amphotericin B. Voriconazole was the most active azole in vitro. All isolates, except Saccharomyces spp., were resistant to echinocandins.

DISCUSSION

Early recognition of rare yeasts as causative agents of BSIs and prompt initiation of appropriate treatment based on current guidelines and expertise remain crucial in efficient patient management.

Intravenous immunoglobulin as a potential treatment for long COVID

INTRODUCTION

On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United States National Institutes of Health (NIH) opened enrollment for the therapeutic arm of the RECOVER initiative, a prospective, randomized study to evaluate new treatment options for long coronavirus disease 2019 (long COVID).

AREAS COVERED

One of the first drugs to be studied in this nationwide initiative is intravenous immunoglobulin (IVIG), which will be a treatment option for subjects enrolled in RECOVER-AUTO, a randomized trial to investigate therapeutic strategies for autonomic dysfunction related to long COVID.

EXPERT OPINION

IVIG is a mixture of human antibodies (human immunoglobulin) that has been widely used to treat a variety of diseases, including immune thrombocytopenia purpura, Kawasaki disease, chronic inflammatory demyelinating polyneuropathy, and certain infections such as influenza, human immunodeficiency virus, and measles. However, the role of IVIG in the treatment of post-COVID-19 conditions is uncertain. This manuscript examines what is known about IVIG in the treatment of long COVID and explores how this therapeutic agent may be used in the future to address this condition.

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.

Candida auris Identification and Profiling by MALDI-ToF Mass Spectrometry

MALDI-ToF MS has become the standard method for routine identification of most medically important yeasts in clinical and public health laboratories and has largely replaced phenotypic identification methods as a first-line identification tool. Fungal identification is based on extensive and well-curated mass spectra libraries usually provided by the manufacturer of the MALDI-ToF MS platform; however, many centers do create specialized or in-house database collections to aid analysis. Most MALDI-ToF MS systems offer simple and standardized workflows for the identification of clinically relevant yeasts to species level with a high throughput, high accuracy, and a low overall cost per test. This makes MALDI-ToF MS an ideal platform for use in routine clinical, diagnostic, and research microbiology laboratories which may lack experience or expertise in the identification of pathogenic fungi.In this chapter we review three standard protocols for the proteomic-based identification of Candida auris isolated from cultures of clinical or environmental surveillance samples in diagnostic and research laboratories.

Consensus guidelines for the diagnosis and management of cryptococcosis and rare yeast infections in the haematology/oncology setting, 2021

Cryptococcosis caused by the Cryptococcus neoformans-Cryptococcus gattii complex is an important opportunistic infection in people with immunodeficiency, including in the haematology/oncology setting. This may manifest clinically as cryptococcal meningitis or pulmonary cryptococcosis, or be detected incidentally by cryptococcal antigenemia, a positive sputum culture or radiological imaging. Non-Candida, non-Cryptococcus spp. rare yeast fungaemia are increasingly common in this population. These consensus guidelines aim to provide clinicians working in the Australian and New Zealand haematology/oncology setting with clear guiding principles and practical recommendations for the management of cryptococcosis, while also highlighting important and emerging rare yeast infections and their recommended management.

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.

MALDI-TOF MS in a Medical Mycology Laboratory: On Stage and Backstage

The implementation of MALDI-TOF MS in medical microbiology laboratories has revolutionized practices and significantly reduced turnaround times of identification processes. However, although bacteriology quickly benefited from the contributions of this technique, adjustments were necessary to accommodate the specific characteristics of fungi. MALDI-TOF MS is now an indispensable tool in clinical mycology laboratories, both for the identification of yeasts and filamentous fungi, and other innovative uses are gradually emerging. Based on the practical experience of our medical mycology laboratory, this review will present the current uses of MALDI-TOF MS and the adaptations we implemented, to allow their practical execution in a daily routine. We will also introduce some less mainstream applications, like those for fungemia, or even still under development, as is the case for the determination of sensitivity to antifungal agents or typing methods.

Coccidioidomycosis in Brazil: Historical Challenges of a Neglected Disease

Coccidioidomycosis is a deep-seated fungal infection that occurs exclusively in semiarid areas in the Americas. In Brazil, coccidioidomycosis occurs exclusively in rural areas in the northeast region and affects counties that are hit by recurrent droughts, poverty and economic stagnation. Since 1978, approximately 136 cases of the disease have been reported in Brazil, according to scientific publications. However, a lack of governmental epidemiological data as well as a similarity to tuberculosis have led scientists and experts to assume that a greater number of cases occur in the country, which are not diagnosed and/or reported. In this review, general characteristics of coccidioidomycosis are presented, followed by a description of the main clinical and epidemiological data of cases in Brazil. The purpose of this article is to discuss the inclusion of coccidioidomycosis in the list of neglected tropical diseases. We believe that the adoption of coccidioidomycosis as a neglected tropical disease will enable the creation of an effective epidemiological surveillance system and the development of feasible public health solutions for its control in vulnerable populations.

Diagnosis of Breakthrough Fungal Infections in the Clinical Mycology Laboratory: An ECMM Consensus Statement

Breakthrough invasive fungal infections (bIFI) cause significant morbidity and mortality. Their diagnosis can be challenging due to reduced sensitivity to conventional culture techniques, serologic tests, and PCR-based assays in patients undergoing antifungal therapy, and their diagnosis can be delayed contributing to poor patient outcomes. In this review, we provide consensus recommendations on behalf of the European Confederation for Medical Mycology (ECMM) for the diagnosis of bIFI caused by invasive yeasts, molds, and endemic mycoses, to guide diagnostic efforts in patients receiving antifungals and support the design of future clinical trials in the field of clinical mycology. The cornerstone of lab-based diagnosis of breakthrough infections for yeast and endemic mycoses remain conventional culture, to accurately identify the causative pathogen and allow for antifungal susceptibility testing. The impact of non-culture-based methods are not well-studied for the definite diagnosis of breakthrough invasive yeast infections. Non-culture-based methods have an important role for the diagnosis of breakthrough invasive mold infections, in particular invasive aspergillosis, and a combination of testing involving conventional culture, antigen-based assays, and PCR-based assays should be considered. Multiple diagnostic modalities, including histopathology, culture, antibody, and/or antigen tests and occasionally PCR-based assays may be required to diagnose breakthrough endemic mycoses. A need exists for diagnostic tests that are effective, simple, cheap, and rapid to enable the diagnosis of bIFI in patients taking antifungals.

Necrotizing cellulitis due to Rhizopus arrhizus in an extremely premature infant

We report an extremely premature infant with necrotizing cellulitis. After minor trauma to the left arm when removing an adhesive sensor, patient developed rapidly progressive cellulitis, which evolved into a necrotic ulcer. Microbiological studies (mass spectroscopy and molecular assay) identified Rhizopus arrhizus as the responsible fungus.

Different detection capabilities by mycological media for Candida isolates from mono- or dual-species cultures

The aim of this study was to compare the Candida bromcresol green (BCG) medium with the chromogenic (CHROM) Brilliance Candida agar and Sabouraud dextrose agar (SDA) media in regard to their capability of detecting Candida isolates from mono- or dual-species cultures. We prepared Candida isolates' suspensions to obtain mono-species (n = 18) or dual-species (n = 153) culture plates per each medium, and three readers independently observed 513 plates at 24-h, 48-h and 72-h incubation time. We scored reading results as correct, over or under detection compared to the expected species number(s). BCG showed significantly higher correct-detection and lower under-detection rates for all Candida species when observed by at least one reader. At 24-h reading, 12 mono-species cultures had correct (or over) detections in all media, whereas 106, 60 and 78 dual-species cultures had correct (or over) detections in BCG, CHROM or SDA, respectively. BCG provides the basis for an accurate laboratory diagnosis of Candida infections.

Necrotizing Mucormycosis of Wounds Following Combat Injuries, Natural Disasters, Burns, and Other Trauma

Necrotizing mucormycosis is a devastating complication of wounds incurred in the setting of military (combat) injuries, natural disasters, burns, or other civilian trauma. Apophysomyces species, Saksenaea species and Lichtheimia (formerly Absidia) species, although uncommon as causes of sinopulmonary mucormycosis, are relatively frequent agents of trauma-related mucormycosis. The pathogenesis of these infections likely involves a complex interaction among organism, impaired innate host defenses, and biofilms related to traumatically implanted foreign materials. Effective management depends upon timely diagnosis, thorough surgical debridement, and early initiation of antifungal therapy.