Innate and Adaptive Immunity to Mucorales

Mucormycosis during COVID-19 era: A retrospective assessment

In a retrospective view, this review examines the impact of mucormycosis on health workers and researchers during the COVID era. The diagnostic and treatment challenges arising from unestablished underlying pathology and limited case studies add strain to healthcare systems. Mucormycosis, caused by environmental molds, poses a significant threat to COVID-19 patients, particularly those with comorbidities and compromised immune systems. Due to a variety of infectious Mucorales causes and regionally related risk factors, the disease's incidence is rising globally. Data on mucormycosis remains scarce in many countries, highlighting the urgent need for more extensive research on its epidemiology and prevalence. This review explores the associations between COVID-19 disease and mucormycosis pathology, shedding light on potential future diagnostic techniques based on the fungal agent's biochemical components. Medications used in ICUs and for life support in ventilated patients have been reported, revealing the challenge of managing this dual onslaught. To develop more effective treatment strategies, it is crucial to identify novel pharmacological targets through "pragmatic" multicenter trials and registries. In the absence of positive mycology culture data, early clinical detection, prompt treatment, and tissue biopsy are essential to confirm the specific morphologic features of the fungal agent. This review delves into the history, pathogens, and pathogenesis of mucormycosis, its opportunistic nature in COVID or immunocompromised individuals, and the latest advancements in therapeutics. Additionally, it offers a forward-looking perspective on potential pharmacological targets for future drug development.

Comprehensive Review on the Virulence Factors and Therapeutic Strategies with the Aid of Artificial Intelligence against Mucormycosis

Mucormycosis, a rare but deadly fungal infection, was an epidemic during the COVID-19 pandemic. The rise in cases (COVID-19-associated mucormycosis, CAM) is attributed to excessive steroid and antibiotic use, poor hospital hygiene, and crowded settings. Major contributing factors include diabetes and weakened immune systems. The main manifesting forms of CAM─cutaneous, pulmonary, and the deadliest, rhinocerebral─and disseminated infections elevated mortality rates to 85%. Recent focus lies on small-molecule inhibitors due to their advantages over standard treatments like surgery and liposomal amphotericin B (which carry several long-term adverse effects), offering potential central nervous system penetration, diverse targets, and simpler dosing owing to their small size, rendering the ability to traverse the blood-brain barrier via passive diffusion facilitated by the phospholipid membrane. Adaptation and versatility in mucormycosis are facilitated by a multitude of virulence factors, enabling the pathogen to dynamically respond to various environmental stressors. A comprehensive understanding of these virulence mechanisms is imperative for devising effective therapeutic interventions against this highly opportunistic pathogen that thrives in immunocompromised individuals through its angio-invasive nature. Hence, this Review delineates the principal virulence factors of mucormycosis, the mechanisms it employs to persist in challenging host environments, and the current progress in developing small-molecule inhibitors against them.

Genetic Basis for Mucormycosis Progression in COVID-19 Patients: From Susceptibility to Severity

The dynamics of COVID-19 and mucormycosis reveal a complex interplay of genetic factors that influence the susceptibility, severity, and immune responses. COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits an increased incidence of mucormycosis, particularly in individuals with comorbidities or corticosteroid therapy. Mucormycosis is a fungal infection that affects the sinuses, orbits, and lungs and demands timely intervention with antifungal medications and surgery because of its life-threatening nature. Research on the genetic underpinnings of this intersection has unveiled key insights into the pathogenicity of Mucorales. Breakthroughs in genetic tools have exposed virulence factors, such as the CotH protein family and high-affinity iron-uptake mechanisms. Genetic susceptibility is a pivotal element in identifying individuals at risk of developing COVID-19, facilitating early detection, and allowing for personalized treatment strategies. DPP9, MIF, and TYK2 are among the genes implicated in COVID-19 severity, emphasizing the intricate relationship between genetic makeup and viral response. The genetic landscape extends to viral entry mechanisms, thereby affecting infection efficiency. Specific polymorphisms in genes such as IFNAR2, OAS3, and TYK2 are associated with COVID-19 severity, indicating shared genetic bases between severe and hospitalized cases. Mucormycosis is genetically predisposed, particularly in immunocompromised individuals. The challenge lies in understanding the genetic factors influencing susceptibility and offering insights into pathogenesis and potential therapeutic avenues. Organ transplantation adds another layer, increasing susceptibility to infections such as COVID-19 and mucormycosis. The impact of immunosuppression on COVID-19 severity remains elusive, necessitating ongoing research on the immunological mechanisms. Despite the challenges posed by emerging SARS-CoV-2 variants, the intricate connection between genetic factors and the interplay of COVID-19 and mucormycosis presents an opportunity for personalized treatment, targeted interventions, and refined public health strategies.

Alternative in-vivo models of mucormycosis

Mucormycosis is still regarded a rare fungal infection, but the high incidences of COVID-associated cases in India and other countries have shown its potential threat to large patient cohorts. In addition, infections by these fast-growing fungi are often fatal and cause disfigurement, badly affecting patients' lives. In advancing our understanding of pathogenicity factors involved in this disease, to enhance the diagnostic toolset and to evaluate novel treatment regimes, animal models are indispensable. As ethical and practical considerations typically favor the use of alternative model systems, this review provides an overview of alternative animal models employed for mucormycosis and discusses advantages and limitations of the respective model.

From Spores to Solutions: A Comprehensive Narrative Review on Mucormycosis

Mucormycosis is an infrequent but fatal illness that mainly affects patients with uncontrolled diabetes mellitus, diabetic ketoacidosis, solid and hematologic neoplasms, organ transplantation, chronic steroid intake, prolonged neutropenia, iron overload states, neonatal prematurity, severe malnutrition, and HIV. Many cases were reported across the world recently following the COVID-19 pandemic. Recent research has led to a better understanding of the pathogenesis of the disease, and global guidelines are now available for managing this serious infection. Herein, we comprehensively review the etiological agents, pathogenesis, clinical presentations, diagnosis, and management of mucormycosis.

Immune and metabolic perturbations in COVID-19-associated pulmonary mucormycosis: A transcriptome analysis of innate immune cells

BACKGROUND AND OBJECTIVES

The mechanisms underlying COVID-19-associated pulmonary mucormycosis (CAPM) remain unclear. We use a transcriptomic analysis of the innate immune cells to investigate the host immune and metabolic response pathways in patients with CAPM.

PATIENTS AND METHODS

We enrolled subjects with CAPM (n = 5), pulmonary mucormycosis (PM) without COVID-19 (n = 5), COVID-19 (without mucormycosis, n = 5), healthy controls (n = 5) without comorbid illness and negative for SARS-CoV-2. Peripheral blood samples from cases were collected before initiating antifungal therapy, and neutrophils and monocytes were isolated. RNA sequencing was performed using Illumina HiSeqX from monocytes and neutrophils. Raw reads were aligned with HISAT-2 pipeline and DESeq2 was used for differential gene expression. Gene ontology (GO) and metabolic pathway analysis were performed using Shiny GO application and R packages (ggplot2, Pathview).

RESULTS

The derangement of core immune and metabolic responses in CAPM patients was noted. Pattern recognition receptors, dectin-2, MCL, FcRγ receptors and CLEC-2, were upregulated, but signalling pathways such as JAK-STAT, IL-17 and CARD-9 were downregulated; mTOR and MAP-kinase signalling were elevated in monocytes from CAPM patients. The complement receptors, NETosis, and pro-inflammatory responses, such as S100A8/A9, lipocalin and MMP9, were elevated. The major metabolic pathways of glucose metabolism-glycolysis/gluconeogenesis, pentose phosphate pathway, HIF signalling and iron metabolism-ferroptosis were also upregulated in CAPM.

CONCLUSIONS

We identified significant alterations in the metabolic pathways possibly leading to cellular iron overload and a hyperglycaemic state. Immune responses revealed altered recognition, signalling, effector functions and a pro-inflammatory state in monocytes and neutrophils from CAPM patients.

Antifungal Activity of Chitosan Polymeric Nanoparticles and Correlation with Their pH Against Mucor circinelloides Causing Mucormycosis, Along with Penicillium notatum and Aspergillus Species

Mucormycosis is uncommon, yet it is more prevalent among individuals with underlying health conditions and those who are immunocompromised. Chitosan is studied because of its appealing properties and diverse applications. The purpose of this work is to synthesize chitosan nanoparticles (CSNPs) by ionic gelation method at various pH levels and test them against Mucor and other filamentous fungus. Field Emission Scanning Electron Microscope, Zeta sizer, Zeta potential, and Fourier Transformed Infrared Spectroscopy were used to characterize CSNPs. Hydrodynamic size increased considerably with increasing pH. Our CSNPs were tested against fungal isolates of Aspergillus Flavus RCMB 02783, Aspergillus Fumigatus RCMB 02564, and Aspergillus Niger RCMB 02588, Penicillium Notatum (NCPF 2881) and   (M. circinelloides CNRMA 03.894) causing mucromycosis. Antifungal activity was investigated using Minimum inhibitory concentration (MIC), Minimum Fungicidal concentration (MFC), Disc diffusion assay, and Antifungal inhibitory percentages methods. The best antifungal efficacy results were obtained through CSNPs prepared at pH = 4.4 at very low concentration for MIC (1.03 or 2.75 μg/mL) with 100% M. circinelloides inhibition followed by pH = 4.6 with MIC (73 or 208 μg/mL) and 93%  M. cirecinelloides inhibition %. Future usage of these materials in masks or wound dressing to avoid fungal infections, including mucormycosis following COVID-19, penicillium, and aspergillosis toxicity and infections.

Phytochemical investigation of Pistacia lentiscus L. var. Chia leaves: A byproduct with antimicrobial potential

Pistacia lentiscus L. var. Chia belongs to the Anacardiaceae family, and it is cultivated only in the south part of Chios island, in Greece. Even though it is renowned for its unique resin, Chios mastic gum (CMG), the tree leaves have also been used in traditional medicine, while the annual pruning generates a large biomass of unused by-products. Thus, the aim of the present study was the detailed phytochemical investigation of P. lentiscus var. Chia leaves towards the search of antimicrobial agents. UPLC-HRMS & HRMS/MS based dereplication methods led to the detailed characterization of the aqueous leaf extract. In addition, twelve compounds were isolated and purified from the methanol extract and were identified using spectroscopic and spectrometric methods (NMR, HRMS) belonging to phenolic acids, tannins, flavonoids and terpenes, with the most interesting being 2-hydroxy-1,8-cineole β-D-glucopyranoside which was isolated for the first time in the Anacardiaceae family. Remarkably, based on NMR data, methanol and aqueous extracts were found to be particularly rich in shikimic acid, a valuable building block for the pharmaceutical industry, for instance in the synthesis of the active ingredient of Tamiflu®, oseltamivir. Finally, extracts (EtOAc, MeOH, H2O) and major compounds i.e., shikimic acid, 2-hydroxy-1,8-cineole β-D-glucopyranoside and myricitrin were evaluated for their antimicrobial properties. MeOH and H2O mastic leaf extracts as well as myricitrin and, particularly, 2-hydroxy-1,8-cineole β-D-glucopyranoside showed significant selective activity against pathogenic Mucorales, but not against Aspergilli (Aspergillus nidulans, Aspergillus fumigatus), Candida albicans or bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis).

Is the production of reactive oxygen and nitrogen species by macrophages associated with better infectious control in female mice with experimentally disseminated and pulmonary mucormycosis?

Different levels of resistance against Rhizopus oryzae infection have been observed between inbred (BALB/c) and outbred (Swiss) mice and are associated with the genetic background of each mouse strain. Considering that macrophages play an important role in host resistance to Rhizopus species, we used different infectious outcomes observed in experimental mucormycosis to identify the most efficient macrophage response pattern against R. oryzae in vitro and in vivo. For this, we compared BALB/c and Swiss macrophage activity before and after intravenous or intratracheal R. oryzae infections. The production of hydrogen peroxide (H2O2) and nitric oxide (NO) was determined in cultures of peritoneal (PMΦ) or alveolar macrophages (AMΦ) challenged with heat-killed spores of R. oryzae. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10) were measured to confirm our findings. Naïve PMΦ from female BALB/c mice showed increased production of H2O2, TNF-α, and IL-10 in the presence of heat-killed spores of R. oryzae. Naïve PMΦ from female Swiss mice were less responsive. Naïve AMΦ from the two strains of female mice were less reactive to heat-killed spores of R. oryzae than PMΦ. After 30 days of R. oryzae intravenous infection, lower fungal load in spleen from BALB/c mice was accompanied by higher production of H2O2 by PMΦ compared with Swiss mice. In contrast, AMΦ from BALB/c mice showed higher production of NO, TNF-α, and IL-10 after 7 days of intratracheal infection. The collective findings reveal that, independent of the female mouse strain, PMΦ is more reactive against R. oryzae upon first contact than AMΦ. In addition, increased PMΦ production of H2O2 at the end of disseminated infection is accompanied by better fungal clearance in resistant (BALB/c) mice. Our findings further the understanding of the parasite-host relationship in mucormycosis.

T-cell dysfunction as a potential contributing factor in post-COVID-19 mucormycosis

BACKGROUND

The second wave of COVID-19 in India was followed by large number of mucormycosis cases. Indiscriminate use of immunosuppressive drugs, underlying diseases such as diabetes, cancers, or autoimmune diseases was thought to be the cause. However, the mortality was not as high as that seen in non-COVID mucormycosis.

OBJECTIVE

To study the detailed characteristics of T-cells for evaluating the underlying differences in the T-cell immune dysfunction in post-COVID and non-COVID mucor patients.

MATERIAL AND METHOD

The study included histopathologically confirmed cases of mucor (13 post-COVID, 13 non-COVID) and 15 healthy individuals (HI). Expression of T-cell activation (CD44, HLADR, CD69, CD38) and exhaustion (CTLA, PD-1, LAG-3 and TIM-3) markers was evaluated by flow cytometry.

RESULTS

All cases showed significant depletion of T-cells compared to HI. Both post-COVID and non-COVID groups showed increased activation and exhaustion as compared to HI. Non-COVID mucor group showed significant activation of CD4+ T cells for HLADR and CD38 (p = .025, p = .054) and marked T-cell exhaustion in form of expression of LAG-3 on both CD4+ T and CD8+ T cells in comparison with post-COVID patients (p = .011, p = .036). Additionally, co-expression of PD-1 & LAG-3 and LAG-3 & TIM-3 on CD8+ T cells was statistically significant in non-COVID mucor patients (p = .016, p = .027).

CONCLUSION

Immunosuppression in non-COVID mucor showed pronounced exhaustion of T-cells in comparison to post-COVID mucor cases implicating T-cell immune dysfunction is much more severe in non-COVID mucor which are in a state of continuous activation followed by extreme exhaustion leading to poorer outcome.

An old confusion: Entomophthoromycosis versus mucormycosis and their main differences

Fungal diseases were underestimated for many years. And the global burden of fungal infections is substantial and has increased in recent years. Invasive fungal infections have been linked to several risk factors in humans which basically depend on the individual homeostasis of the patients. However, many fungi can infect even apparently healthy people. Knowledge of these pathogens is critical in reducing or stopping morbidity and/or mortality statistics due to fungal pathogens. Successful therapeutic strategies rely on rapid diagnosis of the causative fungal agent and the underlying disease. However, the terminology of the diseases was updated to existing phylogenetic classifications and led to confusion in the definition of mucormycosis, conidiobolomycosis, and basidiobolomycosis, which were previously grouped under the now-uncommon term zygomycosis. Therefore, the ecological, taxonomic, clinical, and diagnostic differences are addressed to optimize the understanding and definition of these diseases. The term "coenocytic hyphomycosis" is proposed to summarize all fungal infections caused by Mucorales and species of Basidiobolus and Conidiobolus.

Pathogenesis and Pathology of COVID-Associated Mucormycosis: What Is New and Why

Purpose of Review

There is global increase in the incidence of mucormycosis. However, a sudden increase in the COVID-associated mucormycosis (CAM) was noted, particularly in India, during the second wave of the COVID-19 pandemic. The interplay of factors involved in the pathogenesis is complex. In this review, the influence of pre-existing disease, exaggerated risk factors, altered milieu due to COVID-19 itself and the consequences of its treatment on the host pathogen interactions leading to the disease and morphology of the fungus will be highlighted.

Recent Findings

Hyperglycemia, acidosis, available free iron, lowered host defenses, and the fungal virulence factors promote the growth of Mucorales. There is a high background prevalence of diabetes mellitus (DM) in India. Uncontrolled or undiagnosed DM, COVID-19 itself, and inappropriate administration of corticosteroids in high doses and for prolonged periods result in hyperglycemia. Diabetic ketoacidosis (DKA) and metabolic acidosis due to hypoxia or renal failure contribute to acidic pH and dissociate bound iron from serum proteins. The host defenses are lowered due to COVID-19-induced immune dysregulation, hyperglycemia itself, and administration of corticosteroids and immune suppressants for the treatment of COVID-19. The altered metabolic milieu in the local microenvironment of nose and paranasal sinuses (PNS) promotes specific interaction of glucose-regulated protein-78 (GRP-78) on host cells with spore coat protein homologue (CotH 3) on Mucorales resulting in rhino-orbito-cerebral mucormycosis (ROCM) as the predominant clinical form in CAM. The pathology is extensive soft tissue involvement with angioinvasion and perineural invasion. Melanized hyphae and sporangia were seen on histopathology, which is unique to CAM. While many factors favor the growth of Mucorales in CAM, hyperglycemia, hyperferritinemia, and administration of hyperbaric oxygen result in reactive oxygen species (ROS) and inadequate humidification results in dehydration. Melanization is possibly the adaptive and protective mechanism of Mucorales to escape the unfavorable conditions due to the treatment of COVID-19.

Summary

High background prevalence of DM, inappropriate administration of corticosteroids and immune dysregulation due to COVID-19 favor the growth of Mucorales in CAM. Melanization of Mucorales hyphae and sporangia on histopathology probably represent adaptive and protective mechanism due to the treatment with hyperbaric oxygen with inadequate humidification as well as the metabolic alterations.

Mucormycosis co-infection in COVID-19 patients: An update

Mucormycosis (MCM) is a rare fungal disorder that has recently been increased in parallel with novel COVID-19 infection. MCM with COVID-19 is extremely lethal, particularly in immunocompromised individuals. The collection of available scientific information helps in the management of this co-infection, but still, the main question on COVID-19, whether it is occasional, participatory, concurrent, or coincidental needs to be addressed. Several case reports of these co-infections have been explained as causal associations, but the direct contribution in immunocompromised individuals remains to be explored completely. This review aims to provide an update that serves as a guide for the diagnosis and treatment of MCM patients' co-infection with COVID-19. The initial report has suggested that COVID-19 patients might be susceptible to developing invasive fungal infections by different species, including MCM as a co-infection. In spite of this, co-infection has been explored only in severe cases with common triangles: diabetes, diabetes ketoacidosis, and corticosteroids. Pathogenic mechanisms in the aggressiveness of MCM infection involves the reduction of phagocytic activity, attainable quantities of ferritin attributed with transferrin in diabetic ketoacidosis, and fungal heme oxygenase, which enhances iron absorption for its metabolism. Therefore, severe COVID-19 cases are associated with increased risk factors of invasive fungal co-infections. In addition, COVID-19 infection leads to reduction in cluster of differentiation, especially CD4+ and CD8+ T cell counts, which may be highly implicated in fungal co-infections. Thus, the progress in MCM management is dependent on a different strategy, including reduction or stopping of implicit predisposing factors, early intake of active antifungal drugs at appropriate doses, and complete elimination via surgical debridement of infected tissues.

Diabetes mellitus and other underlying conditions in patients with coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compute the pooled prevalence of diabetes mellitus and other underlying conditions in patients with coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis.

METHOD

A systematic literature review was performed in PubMed, Scopus, Web of Science, Embase and Google Scholar. The cross-sectional studies that reported the frequency of diabetes mellitus in patients with coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis were included.

RESULTS

Eighteen eligible studies with a total number of 3718 patients were included in the current study. The pooled prevalence of diabetes in patients with coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis was 89 per cent and with new-onset diabetes was 32 per cent. The pooled prevalence of steroid use was high (79 per cent) too. The all-cause mortality rate was 24 per cent.

CONCLUSION

Diabetes mellitus was the most frequent underlying condition in patients with coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis. The second most frequent underlying condition was steroid use during coronavirus disease 2019 infection. The appropriate control of hyperglycaemia and rational prescription of steroids during the treatment of coronavirus disease 2019 associated rhino-orbito-cerebral mucormycosis is recommended.

Intracellular cytokine expression in invasive fungal sinusitis and its impact on patient outcome

Background

Cell-mediated immunity plays an important role in host defence against fungal pathogens, regulated by differentiation of lymphocytes towards T-helper 1 or 2 cells. This study reports intracellular cytokine variation in terms of invasive fungal sinusitis type and outcome.

Methods

The mononuclear leukocytes of 15 patients with invasive fungal sinusitis (mucormycosis in 8, aspergillus in 7) were stained with antibodies against intracellular cytokines, after fungal antigen stimulation and culture, and immunophenotyped. Patients were followed up for six months, with clinical course categorised as improvement, worsening or death.

Results

The mean percentages of mononuclear cells producing interleukins 4, 5, 10 and 12, and interferon-γ, in the mucormycosis group were 0.575, 0.284, 8.661, 4.460 and 1.134, respectively, while percentages in the aspergillosis group were 0.233, 0.492, 4.196, 4.466 and 1.533. Cells producing interleukin 4 and 10 were higher in the mucormycosis group, while those producing interleukin-12 and interferon-γ were lower. Cells producing interleukins 4 and 12 were higher in patients with a poor outcome (p-values of 0.0662 and 0.0373, respectively), while those producing interferon-γ were lower (p = 0.0864).

Conclusion

Adaptive cell-mediated immunity is expressed differently in two categories of invasive fungal sinusitis, and the cytokine expression pattern is related to prognosis.

COVID-19 associated multisystemic mucormycosis from India: a multicentric retrospective study on clinical profile, predisposing factors, cumulative mortality and factors affecting outcome

PURPOSE

The clinical course of COVID-19 has been complicated by secondary infections, including bacterial and fungal infections. The rapid rise in the incidence of invasive mucormycosis in these patients is very much concerning. COVID-19-associated mucormycosis was detected in huge numbers during the second wave of the COVID-19 pandemic in India, with several predisposing factors indicated in its pathogenesis. This study aimed to evaluate the epidemiology, predisposing factor, cumulative mortality and factors affecting outcomes among the coronavirus disease COVID-19-associated mucormycosis (CAM).

METHODS

A multicenter retrospective study across three tertiary health care centers in Southern part of India was conducted during April-June 2021.

RESULTS

Among the 217 cases of CAM, mucormycosis affecting the nasal sinuses was the commonest, affecting 95 (44%) of the patients, orbital extension seen in 84 (38%), pulmonary (n = 25, 12%), gastrointestinal (n = 6, 3%), isolated cerebral (n = 2) and disseminated mucormycosis (n = 2). Diabetes mellitus, high-dose systemic steroids were the most common underlying disease among CAM patients. The mucormycosis-associated case-fatality at 6 weeks was 14%, cerebral or GI or disseminated mucormycosis had 9 times higher risk of death compared to other locations. Extensive surgical debridement along with sequential antifungal drug treatment improved the survival in mucormycosis patients.

CONCLUSION

Judicious and appropriate management of the predisposing factor and factors affecting mortality associated with CAM with multi-disciplinary approach and timely surgical and medical management can be much helpful in achieving a successful outcome.

Immunopathology of COVID-19 and its implications in the development of rhino-orbital-cerebral mucormycosis: a major review

PURPOSE

To present a literature review on various immunopathologic dysfunctions following COVID-19 infection and their potential implications in development of rhino-orbital-cerebral mucormycosis (ROCM).

METHODS

A literature search was performed via Google Scholar and PubMed with subsequent review of the accompanying references. Analogies were drawn between the immune and physiologic deviations caused by COVID-19 and the tendency of the same to predispose to ROCM.

RESULTS

Sixty-two articles were reviewed. SARS-CoV-2 virus infection leads to disruption of epithelial integrity in the respiratory passages, which may be a potential entry point for the ubiquitous Mucorales to become invasive. COVID-19 related GRP78 protein upregulation may aid in spore germination and hyphal invasion by Mucorales. COVID-19 causes interference in macrophage functioning by direct infection, a tendency for hyperglycemia, and creation of neutrophil extracellular traps. This affects innate immunity against Mucorales. Thrombocytopenia and reduction in the number of natural killer (NK) cells and infected dendritic cells is seen in COVID-19. This reduces the host immune response to pathogenic invasion by Mucorales. Cytokines released in COVID-19 cause mitochondrial dysfunction and accumulation of reactive oxygen species, which cause oxidative damage to the leucocytes. Hyperferritinemia also occurs in COVID-19 resulting in suppression of the hematopoietic proliferation of B- and T-lymphocytes.

CONCLUSIONS

COVID-19 has a role in the occurrence of ROCM due to its effects at the entry point of the fungus in the respiratory mucosa, effects of the innate immune system, creation of an environment of iron overload, propagation of hyperglycemia, and effects on the adaptive immune system.

COVID-19, Mucormycosis and Cancer: The Triple Threat-Hypothesis or Reality?

COVID-19 has been responsible for widespread morbidity and mortality worldwide. Invasive mucormycosis has death rates scaling 80%. India, one of the countries hit worst by the pandemic, is also a hotbed with the highest death rates for mucormycosis. Cancer, a ubiquitously present menace, also contributes to higher case fatality rates. All three entities studied here are individual, massive healthcare threats. The danger of one disease predisposing to the other, the poor performance status of patients with all three diseases, the impact of therapeutics for one disease on the pathology and therapy of the others all warrant physicians having a better understanding of the interplay. This is imperative so as to effectively establish control over the individual patient and population health. It is important to understand the interactions to effectively manage all three entities together to reduce overall morbidity. In this review article, we search for an inter-relationship between the COVID-19 pandemic, emerging mucormycosis, and the global giant, cancer.

Mini Review: Risk Assessment, Clinical Manifestation, Prediction, and Prognosis of Mucormycosis: Implications for Pathogen- and Human-Derived Biomarkers

Mucormycosis is a fungal disease caused by members of the fungal order Mucorales, which are abundantly found in terrestrial environments. The fungi propagate clonally via mitospores, which are transmitted to humans through the air and cause superficial or invasive infections. The disease has emerged in recent years and coincides generally with immunosuppression on the patient side. Mucormycosis is still rarely recognized in the clinical because of its unspecific symptoms which often triggers misdiagnosis with bacterial or viral infections leading to prolonged therapeutic cycles and loss of valuable time to manage mucormycosis properly. Infected patients develop various clinical forms, most notably ranging from rhinocerebral via pulmonary to gastrointestinal forms. Traditional diagnosis is based on culture and histopathologic examinations of the affected tissue. But, the achievement of a precise result is time-consuming, labor-intensive, requires mycological expertise and the finding appears often too late. A rapid and precise diagnosis is mandatory because symptoms are non-specific and the disease is rapidly progressing with often fatal outcome. Mucormycosis was increasingly associated with other infections and underlying conditions and risk factors causing comorbidities, which are difficult to successfully manage. This mini-review summarizes the current knowledge on the epidemiology and causative agents of mucormycosis, transmission, risk factors, clinical presentation, diagnosis, and highlights the lack of appropriate biomarkers on the pathogen and the host sides for rapid pathogen and host susceptibility detection, respectively. Fungal antigens and single nucleotide polymorphisms (SNPs) in human host genes are useful for the assessment of susceptibility. This mini-review addresses possibilities for early prediction of susceptibility to mucormycosis based on forecasting of the risk of infection with fungal pathogens other than Mucorales. The topic of early prediction and diagnosis of mucormycosis represents a current research gap and highlights the importance of potential future developments in the area of risk assessment, susceptibility prognosis in conjunction with early diagnosis to reduce mortality in patients suffering from mucormycosis.

Mucormycosis and COVID-19-Associated Mucormycosis: Insights of a Deadly but Neglected Mycosis

The ongoing COVID-19 pandemic has quickly become a health threat worldwide, with high mortality and morbidity among patients with comorbidities. This viral infection promotes the perfect setting in patients for the development of opportunistic infections, such as those caused by fungi. Mucormycosis, a rare but deadly fungal infection, has recently increased its incidence, especially in endemic areas, since the onset of the pandemic. COVID-19-associated mucormycosis is an important complication of the pandemic because it is a mycosis hard to diagnose and treat, causing concern among COVID-19-infected patients and even in the already recovered population. The risk factors for the development of mucormycosis in these patients are related to the damage caused by the SARS-CoV-2 itself, the patient's overstimulated immune response, and the therapy used to treat COVID-19, causing alterations such as hyperglycemia, acidosis, endothelial and lung damage, and immunosuppression. In this review, the molecular aspects of mucormycosis and the main risk factors for the development of COVID-19-associated mucormycosis are explained to understand this virus-fungi-host interaction and highlight the importance of this neglected mycosis.

Risk factors for Coronavirus disease-associated mucormycosis

BACKGROUND

The epidemiology of the Coronavirus-disease associated mucormycosis (CAM) syndemic is poorly elucidated. We aimed to identify risk factors that may explain the burden of cases and help develop preventive strategies.

METHODS

We performed a case-control study comparing cases diagnosed with CAM and taking controls as recovered COVID 19 patients who did not develop mucormycosis. Information on comorbidities, glycemic control, and practices related to COVID-19 prevention and treatment was recorded. Multivariate regression analysis was used to identify independent predictors.

RESULTS

A total of 352 patients (152 cases and 200 controls) diagnosed with COVID-19 during April-May 2021 were included. In the CAM group, symptoms of mucormycosis began a mean of 18.9 (SD 9.1) days after onset of COVID-19, and predominantly rhino-sinus and orbital involvement was present. All, but one, CAM cases had conventional risk factors of diabetes and steroid use. On multivariable regression, increased odds of CAM were associated with the presence of diabetes (adjusted OR 3.5, 95% CI 1.1-11), use of systemic steroids (aOR 7.7, 95% CI 2.4-24.7), prolonged use of cloth and surgical masks (vs. no mask, aOR 6.9, 95%CI 1.5-33.1), and repeated nasopharyngeal swab testing during the COVID-19 illness (aOR 1.6, 95% CI 1.2-2.2). Zinc therapy was found to be protective (aOR 0.05, 95%CI 0.01-0.19). Notably, the requirement of oxygen supplementation or hospitalization did not affect the risk of CAM.

CONCLUSION

Judicious use of steroids and stringent glycemic control are vital to preventing mucormycosis. Use of clean masks, preference for N95 masks if available, and minimizing swab testing after the diagnosis of COVID-19 may further reduce the incidence of CAM.

New insights on mucormycosis and its association with the COVID-19 pandemic

COVID-19 continues to cause significant fatality worldwide. Glucocorticoids prove to play essential roles in COVID-19 management; however, the extensive use of steroids together with the virus immune dysregulation may increase the danger of secondary infections with mucormycosis, an angioinvasive fungal infection. Unfortunately, a definite correlation between COVID-19 and elevated mucormycosis infection cases is now clear worldwide. In this review, we discuss the historical record and epidemiology of mucormycosis as well as pathogenesis and associated host immune response, risk factors, clinical presentation, diagnosis and treatment. Special emphasis is given to its association with the current COVID-19 pandemic, including latest updates on COVID-19-associated mucormycosis cases globally, with recommendations for efficacious management.

Covid-19 and mucormycosis superinfection: prospective, obsevational study in a single center

Background:

Mucormycosis (MCR) has been increasingly described in patients with coronavirus disease 2019 (COVID-19), but the epidemiological factors, neurological presentation, and outcome of such patients are not well described.

Aims:

To study the patient demographics, presenting symptoms and signs, the role of co-morbidities, medications used to treat COVID-19, and the outcomes of management and to study the spectrum of neuraxis involvement and its outcome.

Methods:

It was a prospective, observational, cross-sectional hospital-based single center cohort study. Confirmed MCR cases with and without COVID-19 were collected. The study was carried out over a period of 3 months from May to July 2021, followed by 3-month follow-up. Information on epidemiological factors, neurological findings, treatment (including medical and surgical treatment), and outcome was recorded.

Results:

A total of 141 patients were diagnosed with MCR, out of which 98 were COVID-associated MCR (CAM). The CAM incidence was 0.39% among COVID-19-positive patients. The MCR case fatality rate at 90 days was 43.9% but was higher for CAM than for non-CAM patients. Older ages (>50 years), diabetes mellitus, multiple risk factors, diabetic ketoacidosis on admission, brain involvement, and history of COVID-19 pneumonitis were associated with a higher risk for death.

Conclusions:

Possibly because of improper usage of corticosteroids, zinc, oxygen, and tocilizumab, there was sudden surge of cases of MCR in the COVID-19 pandemic. Therefore, treating physicians should use the COVID-19 pneumonia regimen judiciously. Neurological involvement itself is a poor prognostic sign, but combined surgical and medical management exhibited better outcome.

Storm of a rare opportunistic life threatening mucormycosis among post COVID-19 patients: A tale of two pathogens

Mucormycosis is a rare but life-threatening opportunistic fungal infection caused by a group of molds that belong to Zygomycetes of the order Mucorales. These fungi are found in the environment such as soil, decaying vegetation, and organic matters. Sporangiospores present in the environment enter the human body through inhalation or direct skin inoculation by trauma or ingestion and result in pulmonary, cutaneous, and gastrointestinal mucormycosis, respectively, in immunocompromised hosts. Patients with uncontrolled diabetes, hematological malignancies, high-dose glucocorticoid therapy, iron overload, and organ transplantation are at high risk of acquiring mucormycosis. The second wave of severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] affected India severely with the highest number of cases and deaths compared to all other countries. Additionally, the country was affected by emergence of rare but life-threatening mucormycosis. Currently, many coronavirus disease 2019 patients with underlying risk factors such as uncontrolled diabetes, high-dose steroid therapy, and exposure to mechanical ventilation have developed mucormycosis. Inhalation is the most common mode of transmission that results in colonization of sporangiospores in the nose. In immunocompromised host, sporangiospores germinate, and subsequently form hyphae. These hyphae invade into tissues, and produce tissue infarction, necrosis, and thrombosis. Angioinvasion causes hematogenous dissemination to many organs, predominantly to brain, that result in rhino-orbital-cerebral mucormycosis. Clinical characteristics, radio imaging, fungal culture, histopathology, and molecular techniques are the key diagnostic methods. Surgical intervention and aggressive antifungal therapy are the main management strategies. Amphotericin B is the drug of choice for treatment of mucormycosis, whereas posaconazole or isavuconazole is used for step-down therapy and salvage therapy.

"MuCovid-21" study: Mucormycosis at an Indian tertiary care centre during the COVID-19 pandemic

BACKGROUND

Mucormycosis has been reported in several Indian states with the second wave of COVID-19 from January 2021 onwards. This prospective study was conducted with the objective of defining the contribution or association of various known and many suspected factors in the incidence of this disease during the ongoing pandemic.

METHOD

The study included 464 adults with mucormycosis. Basic demographic data were collected. Patient history of COVID infection, its severity, duration of treatment, and oxygen use was taken to assess the association. History of use of antibiotics, steroids, antivirals, biologicals, and other complementary treatments was sought. History of diabetes and other comorbidities was noted. Patients were investigated for mucor confirmation using a nasal swab KOH mount, nasal endoscopy with biopsy, and radiological investigations were done to assess the extent.

RESULTS

Out of 464 patients, 175 were known diabetics, and 157 were treated with steroids during COVID infection. Out of 287 post-COVID patients, 125 (44%) had rhino-mucormycosis (RM), 102 (35%) had rhino-oculo-mucormycosis (ROM) and 60 (21%) had rhino-oculo-cerebral-mucormycosis (ROCM). 162 did not have a history of COVID, of which 93 (57%) had RM, 48 (30%) had ROM and 21 (13%) had ROCM.

CONCLUSION

This study has showed that COVID was not the only factor contributing to mucor, rather other factors such as diabetes, steroid use etc. were also contributory. Many patients who were suffering from mucormycosis did not have a history of COVID. Advanced age, ROCM, and ICU admission were associated with increased mortality.

COVID-19-Associated Mucormycosis, A New Incident in Recent Time: Is An Emerging Disease in The Near Future Impending?

Mucormycosis (also known as black fungus) is caused by fungi of the Zygomycetes class and is the third most common invasive mycosis after candidiasis and aspergillosis. They colonize a large number of patients without invading them. Systemic glucocorticoids are currently used to treat severe Coronavirus disease 19 (COVID-19). In such patients, opportunistic fungal infections are a problem. Although COVID-19-related pulmonary aspergillosis is becoming more common, mucormycosis is still uncommon. Mucormycosis normally appears 10 to 14 days after being admitted to the hospital. Mucormycosis is a rare but dangerous infection that can make extreme COVID-19 worse. Mucormycosis is more likely to occur in people who have diabetes mellitus and other risk factors. Mucormycosis is most likely exacerbated by concurrent glucocorticoid treatment. To improve outcomes, a high index of suspicion and aggressive management is required. Excessive usage of steroids, monoclonal antibodies, and broad-spectrum antibiotics might cause the formation or worsen of a fungal infection. A high index of suspicion and aggressive management are needed. In patients with COVID-19 infection, physicians should be vigilant of the likelihood of subsequent invasive fungal infections. To enhance results in pulmonary mucormycosis, early diagnosis and treatment are critical. Confirmation of the clinical form necessitates a combination of symptoms that are consistent with tissue invasion histologically. Combining various clinical data and the isolation of the fungus from clinical samples in culture is needed for the probable diagnosis of mucormycosis. The organism that causes mucormycosis is identified using macroscopic and microscopic morphological criteria, carbohydrate assimilation, and the maximum temperature at which they can expand. Mucormycosis must be treated with antifungal medication prescribed by a doctor. It may necessitate surgery in some circumstances, and it can result in the loss of the upper jaw and, in some situations, an eye.

Mucormycosis: A triple burden in patients with diabetes during COVID-19 Pandemic

With the upsurge in the cases of COVID-19 around the world, plenty of potential COVID-19 complications are becoming more prevalent, including a higher risk of secondary bacterial and fungal infections. Mucormycosis is one such condition which has high prevalence among individuals with diabetes who were infected with COVID-19.The usage of steroids in the treatment further inflates the risk of infection and exacerbation of disease in pre-existent mucormycosis patients. Generally, Corticosteroid-induced diabetes can arise on long-term steroid medication, increasing the likelihood of mucormycosis. In patients with COVID-19, the indications and dose of corticosteroids should be properly regulated, and persons with diabetes who take insulin or oral anti-diabetic medicines should be cautious. To avoid poor outcomes, strategies to improve glycemic management should be emphasized. This narrative review elucidates different disciplines on rampant use of steroids, iron and zinc supplements as well as the methods utilized as primary or adjunctive treatment of this fatal condition. This article may help to pave the way for robust research that needs to be done to tackle the deadly triple burden of the disease.

The rise in cases of mucormycosis, candidiasis and aspergillosis amidst COVID19

The Coronavirus outbreak globally has changed the medical system and also led to a shortage of medical facilities in both developing and underdeveloped countries. The COVID19 disease, being novel in nature along with high infectivity and frequent mutational rate, has been termed to be fatal across the globe. The advent of infection by SARS-CoV-2 has brought a myriad of secondary complications and comorbidities resulting in additional challenges to the health care system induced by novel therapeutic procedures. The emerging variant with respect to the Indian subcontinent and the associated genetic mutations have worsened the situation at hand. Proper clinical management along with epidemiological studies and clinical presentations in scientific studies and trials is necessary in order to combat the simultaneous waves of emerging strains. This article summarizes three of the major fungal outbreaks in India namely mucormycosis, candidiasis and aspergillosis, and elaborates their subtypes, pathogenesis, symptoms and treatment and detection techniques. A detail of future therapeutics under consideration are also elaborated along with a general hypothesis on how COVID19 is related to immunological advances leading to major widespread fungal infection in the country. The factors that contribute in promoting virus proliferation and invasive fungal infections include cell-mediated immunity, associated immunocompromised conditions and treatment protocols that slows down immune mechanisms. To better comprehend a fungal or bacterial outbreak, it is very important to conduct audits mediated through multicenter national and state research teams for recognizing patterns and studying current cases of fungal infection in both healthy and comorbid groups of COVID19 patients.

Inhibition of extracellular traps by spores of Trichoderma stromaticum on neutrophils obtained from human peripheral blood

Although the genus Trichoderma is widely used as a biocontrol agent in crops, little is known about its potential impact on the human immune system. In mice, our group has shown that exposition to T. asperelloides spores lead to reduced neutrophil counts in the peripheral blood and in the peritoneal cavity. In addition, T. stromaticum spores produced an inflammatory infiltrate on mice lungs, reducing the levels of IFN-γ and IL-10 cytokines, reactive oxygen species, and receptors of microbial patterns. Here we demonstrate that the interaction of human peripheral neutrophils with T. stromaticum spores also leads to a reduced release of neutrophil extracellular traps (NETs) after induction with the NET-inducer agent phorbol 12-myristate 13-acetate. This interaction also reduced the expression levels of multiple microRNAs, such as miR-221, miR-222, miR-223 and miR-27a, as well as genes related to NETs, such as ELANE, MPO and PADI4. Furthermore, T. stromaticum spores affected the expression of the genes SOCS3, TLR4, CSNK2A1, GSDMD, and NFFKBIA, related to the activation of inflammatory immune responses in neutrophils. Overall, our results suggest T. stromaticum as a potential NET inhibitor and as an immunomodulatory agent. Since this fungus is used as biocontrol in crops, our findings point to the importance of advancing our knowledge on the effects of this bioagent on the human immune system. Finally, the study of the active compounds produced by the fungus is also important for the prospection of new drugs that could be used to block the exacerbation of inflammatory immune responses present in several human diseases.

Risk Assessment for Molds in the Vicinity of a Child Requiring Peritoneal Dialysis Living in a Rural Northern German Area

As well as severe immunosuppression, other predisposing factors may facilitate invasive mycosis caused by molds. Chronic kidney disease and the resulting peritoneal dialysis have been reported as factors putting patients at risk of fungal infections from environmental sources. We describe an environmental investigation undertaken to guide exposure prevention for a peritoneal dialysis patient with transient colonization of her nostrils by Lichtheimia corymbifera in a rural area of northern Germany. Systematic screening for airborne and surface-deposited molds enabled targeted recommendations to be made, although Lichtheimia corymbifera itself was not grown from the collected environmental samples. This communication is intended to illustrate how such an investigation can be performed on the basis of the environmental distribution of the molds and how preventive recommendations can be derived from the results.

In Silico Designing of a Multitope Vaccine against Rhizopus microsporus with Potential Activity against Other Mucormycosis Causing Fungi

During the current era of the COVID-19 pandemic, the dissemination of Mucorales has been reported globally, with elevated rates of infection in India, and because of the high rate of mortality and morbidity, designing an effective vaccine against mucormycosis is a major health priority, especially for immunocompromised patients. In the current study, we studied shared Mucorales proteins, which have been reported as virulence factors, and after analysis of several virulent proteins for their antigenicity and subcellular localization, we selected spore coat (CotH) and serine protease (SP) proteins as the targets of epitope mapping. The current study proposes a vaccine constructed based on top-ranking cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and B cell lymphocyte (BCL) epitopes from filtered proteins. In addition to the selected epitopes, β-defensins adjuvant and PADRE peptide were included in the constructed vaccine to improve the stimulated immune response. Computational tools were used to estimate the physicochemical and immunological features of the proposed vaccine and validate its binding with TLR-2, where the output data of these assessments potentiate the probability of the constructed vaccine to stimulate a specific immune response against mucormycosis. Here, we demonstrate the approach of potential vaccine construction and assessment through computational tools, and to the best of our knowledge, this is the first study of a proposed vaccine against mucormycosis based on the immunoinformatics approach.

Pulmonary mucormycosis-a case series

Pulmonary mucormycosis (PM) is a rare disease. Literature about the surgical management of PM in India is sparse. Recently, there has been a surge in the number of cases of mucormycosis in association with the coronavirus disease 2019 (COVID-19) pandemic, igniting the interest in PM. Hence, we endeavoured to analyse our surgical experience in treating PM prior to the pandemic, in a tertiary care centre, to provide insight into this disease. Data of 10 adult patients with isolated PM, who underwent surgery between the years 2009 and 2020, and maintained in our departmental database, were retrieved and analysed.

Newer Horizon of Mesenchymal Stem Cell-Based Therapy in the Management of SARS-CoV-2-Associated Mucormycosis: A Safe Hope for Future Medicine

SARS-CoV-2-infected patients are reported to show immunocompromised behavior that gives rise to a wide variety of complications due to impaired innate immune response, cytokine storm, and thrombo-inflammation. Prolonged use of steroids, diabetes mellitus, and diabetic ketoacidosis (DKA) are some of the factors responsible for the growth of Mucorales in such immunocompromised patients and, thus, can lead to a life-threatening condition referred to as mucormycosis. Therefore, an early diagnosis and cell-based management cosis is the need of the hour to help affected patients overcome this severe condition. In addition, extended exposure to antifungal drugs/therapeutics is found to initiate hormonal and neurological complications. More recently, mesenchymal stem cells (MSCs) have been used to exhibit immunomodulatory function and proven to be beneficial in a clinical cell-based regenerative approach. The immunomodulation ability of MSCs in mucormycosis patient boosts the immunity by the release of chemotactic proteins. MSC-based therapy in mucormycosis along with the combination of short-term antifungal drugs can be utilized as a prospective approach for mucormycosis treatment with promising outcomes. However, preclinical and in mucormyIn mucormycosis, the hyphae of clinical trials are needed to establish the precise mechanism of MSCs in mucormycosis treatment.

The Statewide Epidemiology of Mucormycosis Among Trauma Patients in Florida

OBJECTIVES

Mucormycosis is a rare angioinvasive infection caused by filamentous fungi with a high lethality among the immunocompromised. In healthy people, the innate immune system is sufficient to prevent infection. The exception to this is deep tissue exposure seen during trauma. The purpose of this study is to evaluate the epidemiology of mucormycosis using a statewide population-based data set.

METHODS

This is a retrospective cohort study of all hospital admissions for mucormycosis within the state of Florida from 1997 through the beginning of 2020. A distribution map was created to evaluate for geographic variation. Botanical growth zones, based on plant hardiness, used by state environmental agencies and landscapers were also used to detect possible patterns based on climate conditions throughout Florida. A multivariable regression analysis was performed to account for confounders and limit bias.

RESULTS

A total of 1190 patients were identified for mucormycosis infection. Only 86 of these patients were admitted for trauma. Cutaneous infections were more prevalent among trauma patients while non-trauma patients had more pulmonary infections (P = .04). Trauma patients with infection tended to be younger and less likely to suffer from comorbidities such as immunosuppression (36% vs 46%, P = .07) and diabetes (22.1% vs 47.1%, P ≤ .0001) as compared to their non-trauma counterparts. Mortality was similar with 17.8% for non-trauma patients and 15.1% for traumatized patients (AOR .80 [.42, 1.52]). Length of stay was longer for trauma patients (37.3 vs 23.0, P < .0001). Infections were less prominent in plant hardiness Zone 9 and Zone 10 as compared to Zone 8 (AOR .71 [.61, .82]; AOR .54 [.46, .64], respectively).

CONCLUSION

Trauma patients who develop infection from mucormycosis are at high risk of death despite being a younger and healthier population. Mucormycosis infections were primarily soft tissue based among trauma patients. These infections are more prevalent in colder regions within Florida.

COVID19 associated mucormycosis: Is GRP78 a possible link?

This review aimed to study molecular mechanisms for high incidence of life-threatening mucormycosis infection in COVID19 cases during second wave of SARS CoV2 pandemic in India. Hyperglycaemia, impaired immunity, acidosis, raised ferritin, glucocorticoid therapy, and COVID19 specific other factors have been implicated in pathogenesis of COVID19 associated mucormycosis (CAMM). Endoplasmic reticulum chaperone 'Glucose Related Protein 78' (GRP78), also involved in SARS CoV2 entry, is the host receptor for invasion by Mucorales. GRP78 is over-expressed by SARS CoV2, hyperglycaemia and ferritin. Delta variant of SARS CoV2 and indiscriminate use of steroids were distinguishing features of second wave and appear to upregulate GRP78 through intricate interplay between internal and external milieu. Common invasive fungal infections like candidiasis and aspergillosis, not utilizing GRP78 as receptor, were inconspicuous. Further molecular research to unravel mechanisms involved in the pathogenesis of CAMM shall effectively complement existing strategies for its prevention and treatment.

Risk Factors for Mucormycosis in COVID-19 Patients

: Opportunistic infections, such as mucormycosis, in coronavirus disease 2019 (COVID-19) patients has become a new health challenge. Since opportunistic infections can exacerbate COVID-19 patients' status, it is vital to identify the risk factors to prevent, diagnose, and treat them as soon as possible. Viral, fungal, environmental, and host factors may be responsible for this situation. Long hospital stays, impaired host immune system function due to viral infection, and excessive consumption of glucocorticoids in managing COVID-19 patients are the main risk factors for the increased risk of mucormycosis in COVID-19 patients. Educating health care workers and considering the association between mucormycosis of the paranasal sinuses and different strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the cause of COVID-19 can help prevent invasive fungal sinusitis in COVID-19 patients.

Connecting the Dots: Interplay of Pathogenic Mechanisms between COVID-19 Disease and Mucormycosis

Coronavirus disease (COVID-19)-associated mucormycosis (CAM) is an emerging threat globally, especially in India. More than 40,000 CAM cases have been reported in India. The emergence of CAM cases in India has been attributed to environmental, host, and iatrogenic factors. Mucorales spore burden has been reported globally; however, their presence is higher in tropical countries such as India, contributing to the emergence of CAM. Before the COVID-19 pandemic, patients with diabetes mellitus, haematological malignancies, solid organ transplants, corticosteroid therapy and neutropenia were more prone to mucormycosis, whereas in COVID-19 patients, virus-induced endothelial dysfunction, hyperglycaemia, and immune dysfunction following corticosteroid use increase the risk of acquiring mucormycosis. The interaction of Mucorales spores with the epithelial cells, followed by endothelial invasion, is a crucial step in the pathogenesis of mucormycosis. Endothelial damage and increased endothelial receptor expression induced by COVID-19 infection may predispose patients to CAM. COVID-19 infection may directly induce hyperglycaemia by damaging beta cells of the pancreas or by corticosteroid therapy, which may contribute to CAM pathogenesis. Iron acquisition from the host, especially in diabetic ketoacidosis (DKA) or deferoxamine therapy, is an important virulence trait of Mucorales. Similarly, the hyperferritinaemia caused by COVID-19 may act as a source of iron for Mucorales growth and invasion. In addition, corticosteroid treatment reduces or abolishes the innate immune functions of phagocytic cells contributing to the pathogenesis of CAM. This review aims to discuss primarily the host and iatrogenic factors shared between COVID-19 and mucormycosis that could explain the emergence of CAM.

Multicenter Epidemiologic Study of Coronavirus Disease-Associated Mucormycosis, India

During September-December 2020, we conducted a multicenter retrospective study across India to evaluate epidemiology and outcomes among cases of coronavirus disease (COVID-19)-associated mucormycosis (CAM). Among 287 mucormycosis patients, 187 (65.2%) had CAM; CAM prevalence was 0.27% among hospitalized COVID-19 patients. We noted a 2.1-fold rise in mucormycosis during the study period compared with September-December 2019. Uncontrolled diabetes mellitus was the most common underlying disease among CAM and non-CAM patients. COVID-19 was the only underlying disease in 32.6% of CAM patients. COVID-19-related hypoxemia and improper glucocorticoid use independently were associated with CAM. The mucormycosis case-fatality rate at 12 weeks was 45.7% but was similar for CAM and non-CAM patients. Age, rhino-orbital-cerebral involvement, and intensive care unit admission were associated with increased mortality rates; sequential antifungal drug treatment improved mucormycosis survival. The COVID-19 pandemic has led to increases in mucormycosis in India, partly from inappropriate glucocorticoid use.

Chemical Profiling of Pistacia lentiscus var. Chia Resin and Essential Oil: Ageing Markers and Antimicrobial Activity

Chios Mastic Gum (CMG) and Chios Mastic Oil (CMO) are two unique products of the tree Pistacia lentiscus var. Chia, cultivated exclusively on the Greek island of Chios. In the present study, the method proposed by the European Pharmacopoeia for mastic identification was employed using HPTLC together with an in-house method. A GC-MS methodology was also developed for the chemical characterization of CMOs. α-Pinene and β-myrcene were found in abundance in the fresh oils; however, in the oil of the aged collection, oxygenated monoterpenes and benzenoids such as verbenone, pinocarveol, and α-campholenal were found at the highest rates. Additionally, the antimicrobial activity of Chios Mastic Gums (CMGs) with their respective Chios Mastic Oils (CMOs) was evaluated, with growth tests against the fungi Aspergillus nidulans, Aspergillus fumigatus, Candida albicans, Mucor circinelloides, and Rhizopus oryzae, and the bacteria Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis, with the samples exhibiting a moderate activity. To our knowledge, this is the first time that an HPTLC method is proposed for the analysis of mastic and its essential oil and that a standardized methodology is followed for the distillation of CMO with a parallel assessment of the ageing effect on the oil’s composition.

Corticosteroids alter alveolar macrophage control of Lichtheimia corymbifera spores in an ex vivo mouse model

Alveolar macrophages (AM) are the first-line lung defense against Mucorales in pulmonary mucormycosis. Since corticosteroid use is a known risk factor for mucormycosis, the aim of this study was to describe the role of corticosteroids on AM capacities to control Lichtheimia corymbifera spore growth using a new ex vivo model. An in vivo mouse model was developed to determine the acetate cortisone dose able to trigger pulmonary invasive infection. Then, in the ex vivo model, male BALB/c mice were pretreated with the corticosteroid regimen triggering invasive infection, before AM collection through bronchoalveolar lavage. AMs from corticosteroid-treated mice and untreated control AMs were then exposed to L. corymbifera spores in vitro (ratio 1:5). AM control of fungal growth, adherence/phagocytosis, and oxidative burst were assessed using optical densities by spectrophotometer, flow cytometry, and 2', 7'-dichlorofluoresceine diacetate fluorescence, respectively. Cortisone acetate at 500 mg/kg, at D-3 and at D0, led to pulmonary invasive infection at D3. Co-incubated spores and AMs from corticosteroid-treated mice had significantly higher absorbance (fungal growth) than co-incubated spores and control AMs, at 24 h (P = .025), 36 h (P = .004), and 48 h (P = .001). Colocalization of spores with AMs from corticosteroid-treated mice was significantly lower than for control AMs (7.6 ± 1.9% vs 22.3 ± 5.8%; P = .003), reflecting spore adherence and phagocytosis inhibition. Finally, oxidative burst was significantly increased when control AMs were incubated with spores (P = 0.029), while corticosteroids hampered oxidative burst from treated AMs (P = 0.321). Corticosteroids enhanced fungal growth of L. corymbifera through AM phagocytosis inhibition and burst oxidative decrease in our ex vivo model.

LAY SUMMARY

The aim of this study was to describe the impact of corticosteroids on alveolar macrophage (AM) capacities to control Mucorales growth in a new murine ex vivo model. Corticosteroids enhanced fungal growth of L. corymbifera through AM phagocytosis inhibition and burst oxidative decrease.

Aspergillus-Derived Galactosaminogalactan Triggers Complement Activation on Human Platelets

Invasive fungal infections caused by Aspergillus (A.) and Mucorales species still represent life-threatening diseases in immunocompromised individuals, and deeper knowledge about fungal interactions with elements of innate immunity, such as complement and platelets, appears essential for optimized therapy. Previous studies showed that galactosaminogalactan secreted by A. fumigatus and A. flavus is deposited on platelets, thereby inducing their activation. Since the altered platelet surface is a putative trigger for complement activation, we aimed to study the interplay of platelets with complement in the presence of fungal GAG. Culture supernatants (SN) of A. fumigatus and A. flavus both induced not only GAG deposition but also subsequent deposition of complement C3 fragments on the platelet surface. The SN of a Δuge3 mutant of A. fumigatus, which is unable to synthesize GAG, did not induce complement deposition on platelets, nor did the SN of other Aspergillus species and all tested Mucorales. Detailed analysis revealed that GAG deposition itself triggered the complement cascade rather than the GAG-induced phosphatidylserine exposure. The lectin pathway of complement could be shown to be crucially involved in this process. GAG-induced complement activation on the platelet surface was revealed to trigger processes that might contribute to the pathogenesis of invasive aspergillosis by A. fumigatus or A. flavus. Both pro-inflammatory anaphylatoxins C3a and C5a arose when platelets were incubated with SN of these fungal species; these processes might favor excessive inflammation after fungal infection. Furthermore, platelets were stimulated to shed microparticles, which are also known to harbor pro-inflammatory and pro-coagulant properties. Not only did early processes of the complement cascade proceed on platelets, but also the formation of the terminal complement C5b-9 complex was detected on platelets after incubation with fungal SN. Subsequently, reduced viability of the platelets could be shown, which might contribute to the lowered platelet numbers found in infected patients. In summary, fungal GAG initiates an interplay between complement and platelets that can be supposed to contribute to excessive inflammation, thrombocytopenia, and thrombosis, which are important hallmarks of fatal invasive mycoses.

Host Immune Defense upon Fungal Infections with Mucorales: Pathogen-Immune Cell Interactions as Drivers of Inflammatory Responses

During the last few decades, mucormycosis has emerged as one of the most common fungal infections, following candidiasis and aspergillosis. The fungal order responsible for causing mucormycosis is the Mucorales. The main hallmarks of this infection include the invasion of blood vessels, infarction, thrombosis, and tissue necrosis, which are exhibited at the latest stages of the infection. Therefore, the diagnosis is often delayed, and the rapid progression of the infection severely endangers the life of people suffering from diabetes mellitus, hematological malignancies, or organ transplantation. Given the fact that mortality rates for mucormycosis range from 40 to 80%, early diagnosis and novel therapeutic strategies are urgently needed to battle the infection. However, compared to other fungal infections, little is known about the host immune response against Mucorales and the influence of inflammatory processes on the resolution of the infection. Hence, in this review, we summarized our current understanding of the interplay among pro-inflammatory cytokines, chemokines, and the host-immune cells in response to mucoralean fungi, as well as their potential use for immunotherapies.

Understanding Mucormycoses in the Age of "omics"

Mucormycoses are deadly invasive infections caused by several fungal species belonging to the subphylum Mucoromycotina, order Mucorales. Hallmarks of disease progression include angioinvasion and tissue necrosis that aid in fungal dissemination through the blood stream, causing deeper infections and resulting in poor penetration of antifungal agents to the site of infection. In the absence of surgical removal of the infected focus, antifungal therapy alone is rarely curative. Even when surgical debridement is combined with high-dose antifungal therapy, the mortality associated with mucormycoses is >50%. The unacceptably high mortality rate, limited options for therapy and the extreme morbidity of highly disfiguring surgical therapy provide a clear mandate to understand the molecular mechanisms that govern pathogenesis with the hopes of developing alternative strategies to treat and prevent mucormycoses. In the absence of robust forward and reverse genetic systems available for this taxonomic group of fungi, unbiased next generation sequence (NGS)-based approaches have provided much needed insights into our understanding of many aspects of Mucormycoses, including genome structure, drug resistance, diagnostic development, and fungus-host interactions. Here, we will discuss the specific contributions that NGS-based approaches have made to the field and discuss open questions that can be addressed using similar approaches.

Mucorales Species and Macrophages

Mucormycosis is an emerging fungal infection caused by Mucorales with an unacceptable high mortality rate. Mucorales is a complex fungal group, including eleven different genera that can infect humans. This heterogeneity is associated with species-specific invasion pathways and responses to the host defense mechanisms. The host innate immune system plays a major role in preventing Mucorales growth and host invasion. In this system, macrophages are the main immune effector cells in controlling these fungi by rapid and efficient phagocytosis of the spores. However, Mucorales have evolved mechanisms to block phagosomal maturation and species-specific mechanisms to either survive as dormant spores inside the macrophage, as Rhizopus species, or geminate and escape, as Mucor species. Classical fungal models of mucormycosis, mostly Rhizopus, have made important contributions to elucidate key aspects of the interaction between Mucorales and macrophages, but they lack robust tools for genetic manipulation. The recent introduction of the genetically tractable Mucor circinelloides as a model of mucormycosis offers the possibility to analyze gene function. This has allowed the identification of regulatory pathways that control the fungal response to phagocytosis, including a non-canonical RNAi pathway (NCRIP) that regulates the expression of most genes regulated by phagocytosis.

Pathogenicity patterns of mucormycosis: epidemiology, interaction with immune cells and virulence factors

Fungi of the basal lineage order Mucorales are able to cause infections in animals and humans. Mucormycosis is a well-known, life-threatening disease especially in patients with a compromised immune system. The rate of mortality and morbidity caused by mucormycosis has increased rapidly during the last decades, especially in developing countries. The systematic, phylogenetic, and epidemiological distributions of mucoralean fungi are addressed in relation to infection in immunocompromised patients. The review highlights the current achievements in (i) diagnostics and management of mucormycosis, (ii) the study of the interaction of Mucorales with cells of the innate immune system, (iii) the assessment of the virulence of Mucorales in vertebrate and invertebrate infection models, and (iv) the determination of virulence factors that are key players in the infection process, for example, high-affinity iron permease (FTR1), spore coat protein (CotH), alkaline Rhizopus protease enzyme (ARP), ADP-ribosylation factor (ARF), dihydrolipoyl dehydrogenase, calcineurin (CaN), serine and aspartate proteases (SAPs). The present mini-review attempts to increase the awareness of these difficult-to-manage fungal infections and to encourage research in the detection of ligands and receptors as potential diagnostic parameters and drug targets.

Polysaccharides Cell Wall Architecture of Mucorales

Invasive fungal infections are some of the most life-threatening infectious diseases in the hospital setting. In industrialized countries, the most common fungal species isolated from immunocompromised patients are Candida and Aspergillus spp. However, the number of infections due to Mucorales spp. is constantly increasing and little is known about the virulence factors of these fungi. The fungal cell wall is an important structure protecting fungi from the environment. A better knowledge of its composition should improve our understanding of host-pathogen interactions. Cell wall molecules are involved in tissue adherence, immune escape strategies, and stimulation of host defenses including phagocytosis and mediators of humoral immunity. The fungal cell wall is also a target of choice for the development of diagnostic or therapeutic tools. The present review discusses our current knowledge on the cell wall structure of Mucorales in terms of the polysaccharides and glyco-enzymes involved in its biosynthesis and degradation, with an emphasis on the missing gaps in our knowledge.

Comparative Analysis of Inflammatory Cytokine Release and Alveolar Epithelial Barrier Invasion in a Transwell® Bilayer Model of Mucormycosis

Understanding the mechanisms of early invasion and epithelial defense in opportunistic mold infections is crucial for the evaluation of diagnostic biomarkers and novel treatment strategies. Recent studies revealed unique characteristics of the immunopathology of mucormycoses. We therefore adapted an alveolar Transwell^® A549/HPAEC bilayer model for the assessment of epithelial barrier integrity and cytokine response to Rhizopus arrhizus, Rhizomucor pusillus, and Cunninghamella bertholletiae. Hyphal penetration of the alveolar barrier was validated by 18S ribosomal DNA detection in the endothelial compartment. Addition of dendritic cells (moDCs) to the alveolar compartment led to reduced fungal invasion and strongly enhanced pro-inflammatory cytokine response, whereas epithelial CCL2 and CCL5 release was reduced. Despite their phenotypic heterogeneity, the studied Mucorales species elicited the release of similar cytokine patterns by epithelial and dendritic cells. There were significantly elevated lactate dehydrogenase concentrations in the alveolar compartment and epithelial barrier permeability for dextran blue of different molecular weights in Mucorales-infected samples compared to Aspergillus fumigatus infection. Addition of monocyte-derived dendritic cells further aggravated LDH release and epithelial barrier permeability, highlighting the influence of the inflammatory response in mucormycosis-associated tissue damage. An important focus of this study was the evaluation of the reproducibility of readout parameters in independent experimental runs. Our results revealed consistently low coefficients of variation for cytokine concentrations and transcriptional levels of cytokine genes and cell integrity markers. As additional means of model validation, we confirmed that our bilayer model captures key principles of Mucorales biology such as accelerated growth in a hyperglycemic or ketoacidotic environment or reduced epithelial barrier invasion upon epithelial growth factor receptor blockade by gefitinib. Our findings indicate that the Transwell^® bilayer model provides a reliable and reproducible tool for assessing host response in mucormycosis.

Invasive mucormycosis in children with cancer: A retrospective study from the Infection Working Group of Italian Pediatric Hematology Oncology Association

BACKGROUND

Invasive mucormycosis is a rare but frequently fatal fungal disease. The acute and rapidly progressive evolution causes unfavourable outcome in 22%-59% of patients and its treatment represents a clinical challenge, especially in immunocompromised patients. Current data in paediatric oncological patients are limited.

OBJECTIVES

The infection Working Group of the Italian Association of Pediatric Hematology and Oncology (AIEOP) analysed the episodes of invasive mucormycosis occurred between 2009 and 2016.

PATIENTS

Fifteen cases of proven mucormycosis (male/female 8/7; median age 14.1 years, range 7.7-18.6) were reported after chemotherapy for acute leukaemia and lymphoma (12) and allogeneic stem cell transplantation (3). The aetiology was Rhizopus oryzae 4, Lichtheimia corymbifera 3 and Mucor spp. 8.

RESULTS

Paranasal sinus was the primary site of infection in 14/15 patients combined with orbital involvement (9), central nervous system (8), lung (4), thyroid gland and kidney (1). All patients received liposomal Amphotericin B (L-AmB) (3-10 mg/kg), with surgical debridement in 14/15 cases. Eleven patients received maintenance treatment with posaconazole (9) or isavuconazole (2). Eight out of fifteen patients (53.3%) died, after 3-6 months.

CONCLUSIONS

Mucormycosis involved mainly the sinu-orbital site and affected children >10 years. Despite aggressive treatment with high-dose L-AmB and timely surgical debridement, the mortality rate remains still high.