History of medical mycology in the united states

New pharmacotherapeutic strategies for drug-resistant Candida infections: a review

INTRODUCTION

Candida species produce a wide array of infections ranging from mucocutaneous to systemic infections. Candida albicans remains the most common species identified; however, the non-albicans Candida species have continued to increase as the diagnosis and therapeutic regimens have progressed.

AREAS COVERED

This review with discussion of the various Candida species, especially the non-albicans species, some of the important mechanisms of resistance, and newer in vitro and clinical studies describing the recent and novel antifungal options such as rezafungin, ibrexafungerp, and oteseconazole, along with a novel antifungal, fosmanogepix.

EXPERT OPINION

Initial antifungal therapy is frequently obsolete due to the expansion of antifungal resistance. This is especially true with C. glabrata, C. krusei, and most recently with C. auris. The newer and novel antifungals discussed here will add valuable tools to our antifungal armamentarium to be able to appropriately and adequately treat and manage these difficult infections. Each of the antifungals has unique and novel properties that will expand the arsenal useful to treat these fungal infections in the years to come.

Surge of mucormycosis during the COVID-19 pandemic

Patients with respiratory viral infections are more likely to develop co-infections leading to increased fatality. Mucormycosis is an epidemic amidst the COVID-19 pandemic that conveys a 'double threat' to the global health fraternity. Mucormycosis is caused by the Mucorales group of fungi and exhibits acute angioinvasion generally in immunocompromised patients. The most familiar foci of infections are sinuses (39%), lungs (24%), and skin tissues (19%) where the overall dissemination occurs in 23% of cases. The mortality rate in the case of disseminated mucormycosis is found to be 96%. Symptoms are mostly nonspecific and often resemble other common bacterial or fungal infections. Currently, COVID-19-associated mucormycosis (CAM) is being reported from a number of countries such as the USA, Turkey, France, Mexico, Iran, Austria, UK, Brazil, and Italy, while India is the hotspot for this deadly co-infection, accounting for approximately 28,252 cases up to June 8, 2021. It strikes patients within 12-18 days after COVID-19 recovery, and nearly 80% require surgery. Nevertheless, the mortality rate can reach 94% if the diagnosis is delayed or remains untreated. Sometimes COVID-19 is the sole predisposing factor for CAM. Therefore, this study may provide a comprehensive resource for clinicians and researchers dealing with fungal infections, intending to link the potential translational knowledge and prospective therapeutic challenges to counter this opportunistic pathogen.

Clinical, Epidemiological, and Epizootic Features of Sporothrix brasiliensis in Espírito Santo, Brazil

We verified the clinical-epidemiological, microbiological, and molecular aspects of feline sporotrichosis in Espírito Santo, Brazil, as well as demonstrated the degree of reliability of the cytopathological examination in diagnosis, when compared to fungal culture. From March 2019 to April 2020, 154 suspicious cats were evaluated by collecting data and biological samples. The Cohen's kappa coefficient and the Chi-square independence defined the degree of agreement and the accuracy parameters, respectively. The interobserver agreement was high (Kappa coefficient = 0.96). Sensitivity, specificity, predictive (positive and negative), and accuracy values were 95.0, 97.0, 99.1, 84.2, and 95.5%, respectively. All isolates evaluated were identified as Sporothrix brasiliensis by species-specific PCR. A digital image bank (Padlet) was created with different types of clinical forms and positive slide profiles. We concluded that the cytopathological technique used demonstrated a high degree of reliability. We report an overwhelming occurrence of S. brasiliensis during epizooties in ES.

Tinea Capitis Caused by Microsporum audouninii: A Report of Two Cases from Côte D'Ivoire, West Africa

We report here two cases of tinea capitis caused by Microsporum (M.) audouinii in Côte d’Ivoire, West Africa. The patients were a three-year-old boy and a six-year-old girl who presented with scaly patches on the scalp. The causative fungus was isolated using an adhesive tape-sampling method and cultured on Sabouraud dextrose agar plates. It was identified as M. audouinii both by its macroscopic and microscopic features, confirmed by DNA sequencing. These are the first documented cases of M. audouinii infections confirmed with DNA sequencing to be reported from Côte d’Ivoire. The practicality of the tape-sampling method makes it possible to carry out epidemiological surveys evaluating the distribution of these dermatophytic infections in remote, resource-limited settings.

Molecular epidemiology and in vitro antifungal susceptibility of Trichophyton schoenleinii, agent of tinea capitis favosa

Trichophyton schoenleinii is an anthropophilic dermatophyte usually causing tinea favosa. Only few studies have provided data on molecular epidemiology and antifungal profiles of this fungus due to its limited prevalence after 1950s. Forty-nine strains from Asia (n = 27), Africa (n = 10), Europe (n = 10) and from unknown regions (n = 2) were analysed with amplified fragment length polymorphism fingerprinting (AFLP) to reveal intraspecific genetic diversity in this dataset. Amplified fragment length polymorphism fingerprinting genotyping revealed five clusters which did not correspond to geographic origins or clinical characteristics. Additionally, in vitro antifungal susceptibility to seven antifungals was provided for all strains. Terbinafine, ketoconazole, miconazole and itraconazole proved to be the most effective drugs, followed by griseofulvin. No correlation between genotypes and differences in antifungal susceptibility was observed. It is concluded that the AFLP groups are lineages within a single species.

The molecular immunology of human susceptibility to fungal diseases: lessons from single gene defects of immunity

INTRODUCTION

Fungal diseases are a threat to human health. Therapies targeting the fungus continue to lead to disappointing results. Strategies targeting the host response represent unexplored opportunities for innovative treatments. To do so rationally requires the identification and neat delineation of critical mechanistic pathways that underpin human antifungal immunity. The study of humans with single-gene defects of the immune system, i.e. inborn errors of immunity (IEIs), provides a foundation for these paradigms. Areas covered: A systematic literature search in PubMed, Scopus, and abstracts of international congresses was performed to review the history of genetic resistance/susceptibility to fungi and identify IEIs associated with fungal diseases. Immunologic mechanisms from relevant IEIs were integrated with current definitions and understandings of mycoses to establish a framework to map out critical immunobiological pathways of human antifungal immunity. Expert opinion: Specific immune responses non-redundantly govern susceptibility to their corresponding mycoses. Defining these molecular pathways will guide the development of host-directed immunotherapies that precisely target distinct fungal diseases. These findings will pave the way for novel strategies in the treatment of these devastating infections.

The role of medical mycology societies in combating invasive fungal infections in low- and middle-income countries: A Nigerian model

The discipline of medical mycology has become increasingly relevant in the face of the rising incidence of invasive fungal infections (IFI), which pose diagnostic and therapeutic challenges for contemporary medical practice. While firmly established in developed countries, medical mycology remains obscure in many low- and middle-income countries (LMICs). With a teeming vulnerable populace and an incidence rate of 11.8%, Nigeria has one of the highest estimated burdens of invasive fungal infections (IFIs) in the world. Regardless, the scourge of IFIs has remained silent due to a combination of factors principal amongst which are a lack of awareness and dearth in personnel skilled in diagnosis. The present narrative examines the status of medical mycology practice in Nigeria and chronicles the journey to change the status quo spurred by the Leading International Fungal Education (LIFE)-facilitated burden estimate paper and culminating in the birth of the Medical Mycology Society of Nigeria (MMSN), the pioneer national medical mycology society in Africa. The prospects of tackling the IFI challenge are highlighted from the perspective of the nascent society.

Multicenter, International Study of MIC/MEC Distributions for Definition of Epidemiological Cutoff Values for Sporothrix Species Identified by Molecular Methods

Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic Sporothrix species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of Sporothrixschenckii sensu lato and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and Sporothrix species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301 Sporothrix schenckii sensu stricto, 486 S. brasiliensis, 75 S. globosa, and 13 S. mexicana molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for S. schenckii and S. brasiliensis, respectively: amphotericin B, 4 and 4 μg/ml; itraconazole, 2 and 2 μg/ml; posaconazole, 2 and 2 μg/ml; and voriconazole, 64 and 32 μg/ml. Ketoconazole and terbinafine ECVs for S. brasiliensis were 2 and 0.12 μg/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for S. schenckii, as well as ECVs for S. globosa and S. mexicana These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy.

The Changing Face of Dermatophytic Infections Worldwide

Dermatophytes evolve along with the geography and socioeconomic conditions. Epidermophyton floccosum, Microsporum audouinii and Trichophyton schoenleinii acted as the major pathogens of superficial fungal diseases 100 years ago, but their frequency decreased dramatically since the middle of the twentieth century and they are limited to some less-developed countries nowadays; meanwhile, frequency of Trichophyton rubrum, Trichophyton interdigitale, Trichophyton tonsurans and Microsporum canis increased gradually, and these fungi have become the major species globally. Some other dermatophytes, i.e., Trichophyton violaceum, Trichophyton verrucosum and Microsporum ferrugineum, are mainly endemic in some parts of Africa, Asia and Europe. At present, T. rubrum is the leading pathogen for skin and nail fungal infections, whereas M. canis, T. tonsurans and T. violaceum present as the predominant dermatophytes involved in tinea capitis. Population mobility, changes in human lifestyle and advents of antifungal drugs will continually drive the dermatophyte evolution in the skin microenvironment. Comprehensive observation is needed to better understand this kind of organisms and prospect the trends of their changes in future.

A complex game of hide and seek: the search for new antifungals

Fungal infections directly affect millions of people each year. In addition to the invasive fungal infections of humans, the plants and animals that comprise our primary food source are also susceptible to diseases caused by these eukaryotic microbes. The need for antifungals, not only for our medical needs, but also for use in agriculture and livestock causes a high demand for novel antimycotics. Herein, we provide an overview of the most commonly used antifungals in medicine and agriculture. We also present a summary of the recent progress (from 2010-2016) in the discovery/development of new agents against fungal strains of medical/agricultural relevance, as well as information related to their biological activity, their mode(s) of action, and their mechanism(s) of resistance.

A new approach to drug discovery: high-throughput screening of microbial natural extracts against Aspergillus fumigatus using resazurin

Natural products are an inexhaustible source for drug discovery. However, the validation and selection of primary screening assays are vital to guarantee a selection of extracts or molecules with relevant pharmacological action and worthy of following up. The assay must be rapid, simple, easy to implement, and produce quick results and preferably at a low cost. In this work, we developed and validated a colorimetric microtiter assay using the resazurin viability dye. The parameters of the resazurin method for high-throughput screening (HTS) using natural extracts against Aspergillus fumigatus were optimized and set up. The extracts plus RPMI-1640 modified medium containing the spores and 0.002% resazurin were added per well. The fluorescence was read after 24 to 30 h of incubation. The resazurin proved to be as suitable as Alamar Blue for determining the minimal inhibitory concentration of different antifungals against A. fumigatus and effective to analyze fungicidal and fungistatic compounds. An HTS of 12 000 microbial extracts was carried out against two A. fumigatus strains, and 2.7% of the extracts displayed antifungal activity. Our group has been the first to use this methodology for screening a collection of natural extracts to identify compounds with antifungal activity against the medically important human pathogen A. fumigatus.

In vitro susceptibility testing in Aspergillus species: an update

Aspergillus species are the most common causes of invasive mold infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility testing. Various testing procedures have been proposed, including macro- and micro-dilution, disk diffusion, Etest (AB Biodisk, Sweden) and other commercial tests. Although Aspergillus species are generally susceptible to various compounds, intrinsic and acquired resistance has been documented. Amphotericin B has limited activity against Aspergillus terreus and Aspergillus nidulans. Not surprisingly, continued use of azole-based drugs has the undesirable consequence of elevating the resistance of subsequent isolates from these patients. Several species in the Aspergillus fumigatus complex appear to be resistant to azoles; there is evidence of in vitro and in vivo correlation. Each in vitro susceptibility testing method has its own advantages and disadvantages. Etest is easy to perform and use on a daily basis, yet it is expensive. Disk diffusion is the most attractive alternative method to date, yet we lack sufficient data for aspergilli. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical Laboratory Standard Institute (CLSI) have produced reproducible reference testing methods. This article reviews the available methods for antifungal susceptibility testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing.

Current use of anti-infectives in dermatology

Dermatologic diseases encompass a broad category of pathologic situations. Infection remains a significant aspect of the pathology faced in patient encounters, and it is natural to expect that anti-infectives play a major element in the armamentarium utilized by dermatologists. Aside from the treatment of the classic bacterial and fungal infections, there are now new uses for antiviral agents to help suppress recurrent disease, such as herpes simplex. There is also the novel approach of using anti-infectives, or agents that have been thought to have antimicrobial activity, to treat inflammatory diseases. This review describes anti-infectives, beginning with common antibiotics used to treat bacterial infections. The discussion will then cover the current use of antivirals. Finally, the description of antifungals will be separated, starting with the oral agents and ending with the topical antimycotics. The use of anti-infectives in tropical dermatology has been purposefully left out, and perhaps should be the subject of a separate review. Cutaneous bacterial infections consist chiefly of those microorganisms that colonize the skin, such as species of staphylococcus and streptococcus. Propionibacterium acnes and certain other anaerobes can be involved in folliculitis, pyodermas and in chronic conditions such as hidradenitis suppurativa.

Status of medical mycology education

The number of immunocompromised patients and subsequent invasive fungal infections continues to rise. However, the education of future medical mycologists to engage this growing problem is diminishing. While there are an increasing number of publications and grants awarded in mycology, the time and detail devoted to teaching medical mycology in United States medical schools are inadequate. Here we review the history in medical mycology education and the current educational opportunities. To accurately gauge contemporary teaching we also conducted a prospective survey of microbiology and immunology departmental chairpersons in United States medical schools to determine the amount and content of contemporary education in medical mycology.

Molecular diagnostics of clinical strains of filamentous Basidiomycetes

Eleven clinical and veterinary strains of filamentous Basidiomycetes were compared with 15 reference strains representing the orders Aphyllophorales and Agaricales. The methods used were restriction analysis of small subunit (18S) (SSU) rDNA and internal transcribed spacers (ITS) 1 and 2 and variable domain 9 (V9)-ITS1 sequencing. Six strains were found to belong to the teleomorph genera Schizophyllum or Coprinus, whereas five could not be identified unequivocally. A rapid diagnostic overview is obtained with HaeIII and HinfI digestion of the ITS region.

Nosocomial Candida. Epidemiology, transmission, and prevention

The NNIS and the newly established SCOPE data indicate that the relative proportion of organisms causing nosocomial bloodstream infections has changed over the last decade, with Candida species now being firmly established as one of the most frequent agents. The epidemiology of nosocomial candidemia is continually being refined, but established predisposing factors including immunosuppression and malignancies, use of broad spectrum antibiotics, and use of indwelling central catheters remain as significant risk factors. The high cost of health care and greater attention to continuous quality improvement will stimulate better and more effective ways of diagnosing and treating candida infections using combined clinical and microbiologic acumen. There is room for optimism as newer antifungal agents with reduced toxicities have impact on therapy of candidal infections. Aggressive development of still more agents and reformulations of older agents continue in earnest. Even greater consolation comes from the increased awareness of lay and medical personnel alike regarding the appropriate and judicious use of antimicrobial agents.

Overview of topical therapy for common superficial fungal infections and the role of new topical agents

Until recently the treatment options for superficial fungal infections have been limited mainly to the use of fungistatic drugs of the imidazole class, discovered in the 1960s. The recent development of allylamine and benzylamine compounds provides antifungal agents with fungicidal mechanisms of action. Both imidazole and allylamine/benzylamine drugs interfere with the production of ergosterol, an essential component of the fungal cell membrane; however, the newer drugs act at an earlier stage of the metabolic pathway than the azoles and cause an accumulation of squalene in the fungal cell, which leads to cell death. In vitro test results show that allylamine/benzylamine minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) are lower than the MICs and MFCs of azoles tested by the same methods. In studies using animal models of dermatophytosis, results have shown the efficacy of the allylamine/benzylamine drugs to be superior to that of azole drugs. Clinical trials have also shown significant differences favoring allylamine/benzylamine drugs over imidazoles in the treatment of dermatophytosis. The fungicidal drugs provide earlier evidence of efficacy, higher cure rates with shorter treatment periods, and lower relapse rates than imidazoles in direct-comparison studies. The allylamine/benzylamine drugs have also shown high cure rates in patients with candidiasis.