Rare fungal infectious agents: a lurking enemy

In vitro activity of manogepix and comparators against infrequently encountered yeast and mold isolates from the SENTRY Surveillance Program (2017-2022)

Manogepix is a potent new antifungal agent targeting the fungal Gwt1 enzyme. Manogepix has previously demonstrated potent in vitro activity against clinical isolates of both Candida (except Candida krusei) and Aspergillus species. This study determined the in vitro activity of manogepix and comparators against a large collection of infrequently encountered yeast and molds. Manogepix demonstrated potent in vitro activity against infrequently encountered yeasts exhibiting elevated MIC values to other drug classes, including Candida spp. (MIC50/90, 0.008/0.12 mg/L), Saprochaete clavata (Magnusiomyces clavatus) (MIC50/90, 0.03/0.06 mg/L), Magnusiomyces capitatus (MICrange, 0.016-0.06 mg/L), Rhodotorula minuta (MIC, 0.016 mg/L), and Rhodotorula mucilaginosa (MIC50/90, 0.03/0.12 mg/L). Similarly, manogepix was active against infrequently encountered mold isolates and strains exhibiting elevated MIC/MEC values to echinocandins, azoles, and amphotericin B, including Coprinopsis cinerea (MEC, 0.004 mg/L), Fusarium spp. (MEC50/90, 0.016/0.06 mg/L), Fusarium (Gibberella) fujikuroi species complex (MEC50/90, 0.016/0.03 mg/L), Lomentospora prolificans (MEC50/90, 0.03/0.06 mg/L), Microascus cirrosus (MEC, 0.008 mg/L), Paecilomyces spp. (MEC50/90, ≤0.008/0.016 mg/L), Pleurostomophora richardsiae (MEC, 0.06 mg/L), Sarocladium kiliense (MEC range, 0.016-0.12 mg/L), and Scedosporium spp. (MEC50/90, 0.03/0.06 mg/L). Manogepix demonstrated potent activity against a majority of the infrequently encountered yeast and mold isolates tested including strains with elevated MIC/MEC values to other drug classes. Additional clinical development of manogepix (fosmanogepix) in difficult-to-treat, resistant fungal infections is warranted.

Rare Yeasts in Latin America: Uncommon Yet Meaningful

Systemic infections caused by rare yeasts are increasing given the rise in immunocompromised or seriously ill patients. Even though globally, the clinical significance of these emerging opportunistic yeasts is increasingly being recognized, less is known about the epidemiology of rare yeasts in Latin America. This review collects, analyzes, and contributes demographic and clinical data from 495 cases of infection caused by rare yeasts in the region. Among all cases, 32 species of rare yeasts, distributed in 12 genera, have been reported in 8 Latin American countries, with Trichosporon asahii (49.5%), Rhodotorula mucilaginosa (11.1%), and Saccharomyces cerevisiae (7.8%) the most common species found. Patients were mostly male (58.3%), from neonates to 84 years of age. Statistically, surgery and antibiotic use were associated with higher rates of Trichosporon infections, while central venous catheter, leukemia, and cancer were associated with higher rates of Rhodotorula infections. From all cases, fungemia was the predominant diagnosis (50.3%). Patients were mostly treated with amphotericin B (58.7%). Crude mortality was 40.8%, with a higher risk of death from fungemia and T. asahii infections. Culture was the main diagnostic methodology. Antifungal resistance to one or more drugs was reported in various species of rare yeasts.

Breathing can be dangerous: Opportunistic fungal pathogens and the diverse community of the small mammal lung mycobiome

Human lung mycobiome studies typically sample bronchoalveolar lavage or sputum, potentially overlooking fungi embedded in tissues. Employing ultra-frozen lung tissues from biorepositories, we obtained fungal ribosomal RNA ITS2 sequences from 199 small mammals across 39 species. We documented diverse fungi, including common environmental fungi such as Penicillium and Aspergillus, associates of the human mycobiome such as Malassezia and Candida, and others specifically adapted for lungs (Coccidioides, Blastomyces, and Pneumocystis). Pneumocystis sequences were detected in 83% of the samples and generally exhibited phylogenetic congruence with hosts. Among sequences from diverse opportunistic pathogens in the Onygenales, species of Coccidioides occurred in 12% of samples and species of Blastomyces in 85% of samples. Coccidioides sequences occurred in 14 mammalian species. The presence of neither Coccidioides nor Aspergillus fumigatus correlated with substantial shifts in the overall mycobiome, although there was some indication that fungal communities might be influenced by high levels of A. fumigatus. Although members of the Onygenales were common in lung samples (92%), they are not common in environmental surveys. Our results indicate that Pneumocystis and certain Onygenales are common commensal members of the lung mycobiome. These results provide new insights into the biology of lung-inhabiting fungi and flag small mammals as potential reservoirs for emerging fungal pathogens.

Non-Mucormycetes Causes of Fungal Rhino Sinusitis With Periocular Swelling in COVID-19 With Delta Variant

Objective: To highlight fungi other than mucormycetes as causative agents of rhinosinusitis with periocular swelling in coronavirus (COVID-19) infection caused by Delta variant of SARS-CoV-2 virus and identify the presenting features, risk factors, intervention, and outcomes.

Methods and analysis: A retrospective interventional study of 96 patients with fungal rhinosinusitis and periocular swelling was done in patients with concurrent or recovered COVID-19 infection with the Delta variant (B.1.617.2) of SARS-CoV-2 virus in India. All patients with mucormycetes infection were excluded. Clinical presentation, medical history, blood reports, and imaging were analyzed. Management was by intravenous (IV) liposomal amphotericin B and functional endoscopic sinus surgery (FESS) with paranasal sinus debridement. Limited orbital debridement with or without transcutaneous retrobulbar liposomal amphotericin B (TRAMB) was done in patients with orbital involvement. Postoperative antifungal therapy was decided on the basis of the causative fungi.

Results: Four cases of Aspergillus and one each of Fusarium, Curvularia, and Penicillium-associated fungal rhinosinusitis with periocular swelling were seen. Signs of orbital involvement on MRI were present in all four of them. Two of these showed partial third-nerve palsy while one case with aspergillosis suffered cavernous sinus thrombosis. Proptosis was not witnessed in any case. History of diabetes and use of steroids was seen in all patients. All patients had mild to moderate COVID-19 with oxygen supplementation needed in one. No mortality, acute vision loss, or exenteration took place.

Conclusion: Aspergillus, Fusarium, Curvularia, and Penicillium were non-mucormycetes causes of fungal rhinosinusitis with periocular swelling in COVID-19 infection with the Delta variant (B.1.617.2) of SARS COV-2 virus. Few cases showed orbital and intracranial involvement.

Intracerebral mucormycosis after COVID-19: illustrative cases

BACKGROUND

In this case report the authors present two female patients with intracranial mucormycosis after coronavirus disease 2019 (COVID-19).

OBSERVATIONS

The first patient was a 30-year-old woman with no past medical history or allergies who presented with headaches and vomiting. Magnetic resonance imaging (MRI) and computed tomography of the skull showed an endonasal infection, which had already destroyed the frontal skull base and caused a large frontal intracranial abscess. The second patient was a 29-year-old woman with multiple pre-existing conditions, who was initially admitted to the hospital due to a COVID-19 infection and later developed a hemiparesis of the right side. Here, the MRI scan showed an abscess configuration in the left motor cortex. In both cases, rapid therapy was performed by surgical clearance and abscess evacuation followed by antifungal, antidiabetic, and further supportive treatment for several weeks.

LESSONS

Both cases are indicative of a possible correlation of mucormycosis in the setting of severe immunosuppression involved with COVID-19, both iatrogenic with the use of steroids and previous medical history. Furthermore, young and supposedly healthy patients can also be affected by this rare disease.

Invasive and Subcutaneous Infections Caused by Filamentous Fungi: Report from a Portuguese Multicentric Surveillance Program

Invasive fungal infections (IFI) have significantly increased over the past years due to advances in medical care for the at-risk immunocompromised population. IFI are often difficult to diagnose and manage, and can be associated with substantial morbidity and mortality. This study aims to contribute to understanding the etiology of invasive and subcutaneous fungal infections, their associated risk factors, and to perceive the outcome of patients who developed invasive disease, raising awareness of these infections at a local level but also in a global context. A laboratory surveillance approach was conducted over a seven-year period and included: (i) cases of invasive and subcutaneous fungal infections caused by filamentous/dimorphic fungi, confirmed by either microscopy or positive culture from sterile samples, (ii) cases diagnosed as probable IFI according to the criteria established by EORTC/MSG when duly substantiated. Fourteen Portuguese laboratories were enrolled. Cases included in this study were classified according to the new consensus definitions of invasive fungal diseases (IFD) published in 2020 as follows: proven IFI (N = 31), subcutaneous fungal infection (N = 23). Those proven deep fungal infections (N = 54) totalized 71.1% of the total cases, whereas 28.9% were classified as probable IFI (N = 22). It was possible to identify the etiological fungal agent in 73 cases (96%). Aspergillus was the most frequent genera detected, but endemic dimorphic fungi represented 14.47% (N = 11) of the total cases. Despite the small number of cases, a high diversity of species were involved in deep fungal infections. This fact has implications for clinical and laboratory diagnosis, and on the therapeutic management of these infections, since different species, even within the same genus, can present diverse patterns of susceptibility to antifungals.

Exclusion of Mucorales Co-Infection in a Patient with Aspergillus flavus Sinusitis by Fluorescence In Situ Hybridization (FISH)

Invasive fungal infections are associated with increased mortality in hematological patients. Despite considerable advances in antifungal therapy, the evaluation of suspected treatment failure is a common clinical challenge requiring extensive diagnostic testing to rule out potential causes, such as mixed infections. We present a 64-year-old patient with secondary AML, diabetes mellitus, febrile neutropenia, and sinusitis. While cultures from nasal tissue grew Aspergillus flavus, a microscopic examination of the tissue was suggestive of concomitant mucormycosis. However, fluorescence in situ hybridization (FISH) using specific probes targeting Aspergillus and Mucorales species ruled out mixed infection. This was confirmed by specific qPCR assays amplifying the DNA of Aspergillus, but not of Mucorales. These results provided a rational basis for step-down targeted therapy, i.e., the patient received posaconazole after seven days of calculated dual therapy with liposomal amphotericin B and posaconazole. Despite clinical response to the antifungal therapy, he died due to the progression of the underlying disease within two weeks after diagnosis of fungal infection. Molecular diagnostics applied to tissue blocks may reveal useful information on the etiology of invasive fungal infections, including challenging situations, such as with mixed infections. A thorough understanding of fungal etiology facilitates targeted therapy that may improve therapeutic success while limiting side effects.

Synthesis of biotinylated pentasaccharide structurally related to a fragment of glucomannan from Candida utilis

The polysaccharide mannan is the main surface antigen of the cell wall of Candida fungi, playing an important role in the pathogenesis of diseases caused by these mycopathogens. Mannan has a complex, comb-like structure and includes a variety of structural units, with their combination varying depending on the Candida species and strain. Glucomannan, a polysaccharide from Candida utilis, contains terminal α-d-glucose residues attached to oligomannoside side chains. This paper describes the first synthesis of a pentasaccharide structurally related to C. utilis glucomannan fragment, which is an α-(1→2)-linked tetramannoside terminated at the non-reducing end by an α-d-glucopyranosyl residue. The pentasaccharide was obtained as a 3-aminopropyl glycoside, which made it possible to synthesize also its biotinylated derivative, suitable for various glycobiological studies. The most complicated step in the pentasaccharide synthesis was stereoselective 1,2-cis-glycosylation to attach the α-d-glucopyranosyl residue. This was accomplished using a glucosyl donor specially developed in our laboratory, the protecting groups of which provide the necessary α-stereoselectivity. The target biotinylated pentasaccharide thus obtained will be used in the future as a model antigen for the detection of immunodeterminant epitopes of Candida mannans.

First Case of Subcutaneous Mycoses Caused by Dirkmeia churashimaensis and a Literature Review of Human Ustilaginales Infections

Objective

Dirkmeia churashimaensis, belonging to Ustilaginales fungi, has never been reported as clinical pathogenic until very recently. In this study, we report an unusual subcutaneous infection with Dirkmeia churashimaensis and reviewed all human Ustilaginales infections. The aim is to better understand their epidemiology, infection type, risk factors, and the sensitivity to antifungal agents.

Methods

An 80-year-old female farmer developed extensive plaques and nodules on her left arm within 2 years. Pathological and microbiological examinations identified a new pathological agent, Dirkmeia churashimaensis, as the cause of this infection. The patient was successfully cured by oral itraconazole. We reviewed a total of 31 cases of Ustilaginales cases, among of which only three were skin infections.

Results

Local barrier damage (i.e., surgery, trauma, and basic dermatosis) and systemic immunodeficiency (i.e., preterm and low birthweight, Crohn’s disease, malignant cancer, and chemotherapy) are risk factors for Ustilaginales infection. The D1/D2 and ITS regions are the frequently used loci for identifying the pathogens together with phenotype. Most patients could survive due to antifungal treatment, whereas seven patients died. Amphotericin B, posaconazole, itraconazole, and voriconazole showed good activity against these reported strains, whereas fluconazole, 5-flucytosine, and echinocandins usually showed low susceptibility. Itraconazole had good efficiency for subcutaneous infections.

Conclusions

The present case study and literature review reveal that Ustilaginales can be opportunistic pathogenic normally in immunocompromised and barrier damage people. A proper identification of fungi can be crucial for clinical treatment, and more data of antifungal are needed for choice of medication against this kind of infections.

Humoral immune responses against facultative pathogen Candida utilis in atopic patients with vulvovaginal candidiasis. Candida utilis glucomannan - New serologic biomarker

Vulvovaginal candidiasis is one of the most commonly reported female genital tract infections, affecting approximately 70-75% of childbearing age women at least once during their lifetime. Approximately 50% of patients have refractory episodes and in 5-10% of cases the disease has a chronic course. The fungal cell wall represents the important host-invader interface. Cell-wall polysaccharides represent biological response modifiers and the pathogen-associated molecular patterns and virulence factors. Glycans are sensed by germ-line encoded pattern recognition receptors and reactively participate in immune system cell signaling. The most dominant cell-wall antigenic structures of Candida species as ß-glucan, α- and ß-mannans, glucomannan and other immunogenic polysaccharides are of particular relevancy for specific in vitro diagnosis and long-term follow-up of the Candida infection. In this study we assessed the immunobiological activity of facultative pathogen Candida utilis cell glucomannan and its effectivity as in vitro serological marker for antibody testing. The novel serologic assay has been developed and optimized for C. utilis serodiagnosis. The comparison assays were performed to establish relationship between antibodies against C. utilis, C. albicans and S. cerevisiae main cell-wall antigens in patient sera. The study evaluates applicability of glucomannan as serodiagnostic antigen and as a trigger of antigenspecific IgG, IgM and IgA antibody isotypes in the cohort of 35 atopic female subjects with recurrent vulvovaginal candidiasis. Statistically significant sera values of specific anti-glycan IgM and IgA class antibodies were revealed. The results are suggestive for efficient serological application of C.utilis glucomannan as in vitro disease marker and prospectively for follow-up of the specific long-term antimycotic therapy.

Expression Patterns in Reductive Iron Assimilation and Functional Consequences during Phagocytosis of Lichtheimia corymbifera, an Emerging Cause of Mucormycosis

Iron is an essential micronutrient for most organisms and fungi are no exception. Iron uptake by fungi is facilitated by receptor-mediated internalization of siderophores, heme and reductive iron assimilation (RIA). The RIA employs three protein groups: (i) the ferric reductases (Fre5 proteins), (ii) the multicopper ferroxidases (Fet3) and (iii) the high-affinity iron permeases (Ftr1). Phenotyping under different iron concentrations revealed detrimental effects on spore swelling and hyphal formation under iron depletion, but yeast-like morphology under iron excess. Since access to iron is limited during pathogenesis, pathogens are placed under stress due to nutrient limitations. To combat this, gene duplication and differential gene expression of key iron uptake genes are utilized to acquire iron against the deleterious effects of iron depletion. In the genome of the human pathogenic fungus L. corymbifera, three, four and three copies were identified for FRE5, FTR1 and FET3 genes, respectively. As in other fungi, FET3 and FTR1 are syntenic and co-expressed in L. corymbifera. Expression of FRE5, FTR1 and FET3 genes is highly up-regulated during iron limitation (Fe-), but lower during iron excess (Fe+). Fe- dependent upregulation of gene expression takes place in LcFRE5 II and III, LcFTR1 I and II, as well as LcFET3 I and II suggesting a functional role in pathogenesis. The syntenic LcFTR1 I–LcFET3 I gene pair is co-expressed during germination, whereas LcFTR1 II- LcFET3 II is co-expressed during hyphal proliferation. LcFTR1 I, II and IV were overexpressed in Saccharomyces cerevisiae to represent high and moderate expression of intracellular transport of Fe3+, respectively. Challenge of macrophages with the yeast mutants revealed no obvious role for LcFTR1 I, but possible functions of LcFTR1 II and IVs in recognition by macrophages. RIA expression pattern was used for a new model of interaction between L. corymbifera and macrophages.

Evaluation of Rhodotorula spp. contamination in hospital environments

Microbiological monitoring of air and surfaces is a valuable tool for assessing the level of environmental contamination by bacteria and fungi in hospitals, especially in high-risk wards. The presence of these microorganisms requires strict control in view of their role as opportunistic pathogens. As regard yeasts, Candida albicans is one of the main opportunistic pathogens. However, in recent years, many other "non-Albicans" species have been identified that are implicated in the onset of both localised infections in immunocompetent patients and systemic infections in immunocompromised patients. The aim of the work was to evaluate the frequency of isolation of Rhodotorula spp. in environmental samples of hospital origin in order to highlight how its presence may represent an increased risk for hospitalised patients. The samples were taken in at-risk wards, divided into six types of environments, in three hospitals in southern Sardinia between 2016 and 2019. The presence of moulds and yeasts was higher in the air (55.7%) than on surfaces (44.3%) in the hospital environments (p < 0.001). Similarly, the isolation frequency of Rhodotorula spp. was found to be greater (p < 0.001) in the air (14.2%) than on surfaces (9.2%). This study made it possible to evaluate the presence of pathogenic fungi in hospital environments, paying particular attention to Rhodotorula spp. since it is an emerging opportunistic yeast. It also highlights the importance of control measures especially in those where immunocompromised patients are present.

Ebselen and diphenyl diselenide against fungal pathogens: A systematic review

Fungal infections are one of the most prevalent diseases in the world and there is a lack of new antifungal drug development for these diseases. We conducted a systematic review of the literature regarding the in vitro antifungal activity of the organoselenium compounds ebselen (Eb) and diphenyl diselenide [(PhSe)2]. A systematic review was carried out based on the search for articles with data concerning Minimal Inhibitory Concentration (MIC) values, indexed in international databases and published until August 2020. A total of 2337 articles were found, and, according to the inclusion and exclusion criteria used, 22 articles were included in the study. Inhibitory activity against 96% (200/208) and 95% (312/328) of the pathogenic fungi tested was described for Eb and [(PhSe)2], respectively. Including in these 536 fungal isolates tested, organoselenium activity was highlighted against Candida spp., Cryptococcus ssp., Trichosporon spp., Aspergillus spp., Fusarium spp., Pythium spp., and Sporothrix spp., with MIC values lower than 64 μg/mL. In conclusion, Eb and [(PhSe)2] have a broad spectrum of in vitro inhibitory antifungal activity. These data added with other pharmacological properties of these organoselenium compounds suggest that both compounds are potential future antifungal drugs. Whether MICs toward the upper end of the ranges described here are compatible with efficacious therapy, and whether they may achieve such end as a result of the favorable non-antimicrobial effects of selenium on the host, requires more in vivo testing.

Candida auris-an impending threat: A case report from home

Candida auris has been identified as an invasive fungal organism of outbreaks globally. Due to its striking ability to colonize the skin and readily transmit from person-to-person, it is being categorized as a public health threat. Infected patients are not only characteristically critically ill, but delayed identification along with limited options for effective antifungals makes this nosocomial infection worrisome for clinicians. The risk of persistence of fungus as a contaminant in hospital rooms and on medical equipment is also a concern for health care facilities. In this case report, we described fungemia with Candida auris secondary to pyelonephritis in a patient, which escalated to septic shock and was treated with micafungin. The unique feature about this case was the patient presented from home with no history of recent hospitalization and no evident predisposing risk factors such as immunosuppression, indwelling or central venous catheters at the time of admission.

Epidemiological study of Trichosporon asahii infections over the past 23 years

Trichosporon is a yeast-like basidiomycete, a conditional pathogenic fungus that is rare in the clinic but often causes fatal infections in immunocompromised individuals. Trichosporon asahii is the most common pathogenic fungus in this genus and the occurrence of infections has dramatically increased in recent years. Here, we report a systematic literature review detailing 140 cases of T. asahii infection reported during the past 23 years. Statistical analysis shows that T. asahii infections were most frequently reported within immunodeficient or immunocompromised patients commonly with blood diseases. Antibiotic use, invasive medical equipment and chemotherapy were the leading risk factors for acquiring infection. In vitro susceptibility, clinical information and prognosis analysis showed that voriconazole is the primary drug of choice in the treatment of T. asahii infection. Combination treatment with voriconazole and amphotericin B did not show superiority over either drug alone. Finally, we found that the types of infections prevalent in China are significantly different from those in other countries. These results provide detailed information and relevant clinical treatment strategies for the diagnosis and treatment of T. asahii infection.

Geotrichosis Presenting As Funguria and Asymptomatic Urinary Tract Infection in a Patient with Renal Cyst

Fungi are a versatile group of microorganisms that exist in three morphological forms, which include the yeasts (oval/spherical budding cells), true fungi (produce long filamentous, branching structures called as hyphae/mycelia), and dimorphic fungi (show both yeast at 370C and hyphal forms at room temperature). Most fungi are present in the environment and live as saprophytes. Some fungal species like the Candida are present in the human respiratory, intestinal, and genitourinary tract as commensals. Some fungi cause infections in humans and animals (dermatophytes). Few other fungal species are responsible for opportunistic infections, mostly in debilitated and immunosuppressed individuals. Geotrichum is one such fungus, which is present in the soil, dead, and decomposing organic matter, and may contaminate food, fruits, and vegetables. Geotrichosis is the infection caused by Geotrichum species. Due to its similarity in morphology, clinical features, and the pathogenicity with common fungi like the Candida species, and others, its clinical significance is undermined. This report presents a case of funguria and asymptomatic urinary tract infection caused by Geotrichum species in a patient with a renal cyst.

Bridging the knowledge gap on mycoses in Africa: Setting up a Pan-African Mycology Working Group

Most African countries have poorly funded and overburdened health systems. Additionally, a high prevalence of HIV in Sub-Saharan Africa contributes to a high burden of opportunistic fungal infections. Data generated by GAFFI from 15 of 57 African countries revealed that an estimated 47 million Africans suffer from fungal diseases, of whom an estimated 1.7 million suffer from a serious fungal infection annually. Almost all African countries lack a surveillance system for fungal infections with the exception of South Africa. South Africa is also the only African country with a national mycology reference laboratory. Across the continent, there is a pervasive picture of inadequate/poor diagnostic capacity, low level of awareness among healthcare workers and policymakers and unavailability and non-accessibility to essential antifungal medications. Recent outreach efforts by the International Society for Human and Animal Mycology (ISHAM) and the European Confederation of Medical Mycology (ECMM) have aimed to increase involvement of African countries and experts in global initiatives such as "One World One Guideline" and also the ECMM Academy. Recently, under the auspices of ISHAM, the African sub-region created a network of mycology experts whose goal is to organise and engage African leaders in the field of medical mycology. The aim of this ISHAM Working Group was to facilitate interaction and synergy among regional leaders in order to develop educational programmes for capacity building to aid in the diagnosis and care of patients with fungal infections in Africa. The working group will also encourage country initiatives to develop clinical guidelines, to support surveys and to support the establishment of reference mycology laboratories.