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

"We've got to get out"-Strategies of human pathogenic fungi to escape from phagocytes

Human fungal pathogens are a deadly and underappreciated risk to global health that most severely affect immunocompromised individuals. A virulence attribute shared by some of the most clinically relevant fungal species is their ability to survive inside macrophages and escape from these immune cells. In this review, we discuss the mechanisms behind intracellular survival and elaborate how escape is mediated by lytic and non-lytic pathways as well as strategies to induce programmed host cell death. We also discuss persistence as an alternative to rapid host cell exit. In the end, we address the consequences of fungal escape for the host immune response and provide future perspectives for research and development of targeted therapies.

Deficient Phagocytosis in Circulating Monocytes from Patients with COVID-19-Associated Mucormycosis

Cases of rhino-orbital mucormycosis in patients suffering from severe coronavirus disease 2019 (COVID-19) were reported in different parts of the world, especially in India. However, specific immune mechanisms that are linked to susceptibility to COVID-19-associated mucormycosis (CAM) remain largely unexplored. We aimed to explore whether the differential regulation of circulating cytokines in CAM patients had any potential pathogenic links with myeloid phagocyte function and susceptibility to mucormycosis. A small cohort of Indian patients suffering from CAM (N = 9) as well as COVID-19 patients with no evidence of mucormycosis (N = 5) were recruited in the study. Venous blood was collected from the patients as well as from healthy volunteers (N = 8). Peripheral blood mononuclear cells and plasma were isolated. Plasma samples were used to measure a panel of 48 cytokines. CD14⁺ monocytes were isolated and used for a flow cytometric phagocytosis assay as well as a global transcriptome analysis via RNA-sequencing. A multiplex cytokine analysis of the plasma samples revealed reduction in a subset of cytokines in CAM patients, which is known to potentiate the activation, migration, or phagocytic activity of myeloid cells, compared to the COVID-19 patients who did not contract mucormycosis. Compared to monocytes from healthy individuals, peripheral blood CD14⁺ monocytes from CAM patients were significantly deficient in phagocytic function. The monocyte transcriptome also revealed that pathways related to endocytic pathways, phagosome maturation, and the cytoskeletal regulation of phagocytosis were significantly downregulated in CAM patients. Thus, the study reports a significant deficiency in the phagocytic activity of monocytes, which is a critical effector mechanism for the antifungal host defense, in patients with CAM. This result is in concordance with results regarding the specific cytokine signature and monocyte transcriptome. IMPORTANCE A number of cases of mucormycosis, often fatal, were reported among severe COVID-19 patients from India as well as from some other parts of the world. However, specific immunocellular mechanisms that underlie susceptibility to this fungal infection in COVID-19 remain largely unexplored. Our study reports a deficiency in phagocytosis by monocytes in COVID-19 patients who are concomitantly afflicted with mucormycosis, with this deficiency being linked to a characteristic monocyte transcriptome as well as a circulating cytokine signature. The functional phenotype and cytokine signature of the monocytes may provide useful biomarkers for detecting potential susceptibility to mucormycosis in COVID-19 as well as in other viral infections.

The application of metagenomic next-generation sequencing in patients with infection or colonization caused by Lichtheimia species

Background

Mucormycosis is considered the fourth most common invasive fungal disease after candidiasis, aspergillosis and cryptococcosis. Lichtheimia species accounted for 5%-29% of all mucormycosis. However, available data on species-specific analysis of Lichtheimia infections are limited.

Methods

This study included nine patients hospitalized in five hospitals in two cities in south China with mucormycosis or colonization caused by Lichtheimia species, diagnosed mainly by metagenomic next-generation sequencing (mNGS). The corresponding medical records were reviewed, and the clinical data analyzed included demographic characteristics, site of infection, host factors and type of underlying disease, diagnosis, clinical course, management, and prognosis.

Results

In this study, nine patients with Lichtheimia infections or colonization had a recent history of haematological malignancy (33.3%), solid organ transplants (33.3%), pulmonary disease (22.2%), and trauma (11.1%) and were categorized as 11.1% (one case) proven, 66.7% (six cases) probable mucormycosis and 22.2% (two cases) colonization. Pulmonary mucormycosis or colonization was the predominant presentation in 77.8% of cases and mucormycosis caused by Lichtheimia resulted in death in four out of seven patients (57.1%).

Conclusion

These cases highlight the importance of early diagnosis and combined therapy for these sporadic yet life-threatening infections. Further studies on the diagnosis and control of Lichtheimia infection in China are required.

Perturbations of immune landscape in COVID-19 associated mucormycosis

BACKGROUND

A rise in secondary fungal infections during the COVID-19 pandemic necessitates a deeper understanding of the associated immunological perturbations.

OBJECTIVES

To evaluate the clinical and immunological characteristics observed in patients with COVID-19 associated mucormycosis (CAM) infection.

PATIENTS/ METHODS

Cases of mucormycosis with or post-COVID-19 infection were compared with cases of acute COVID-19 and convalescent COVID-19. Lymphocyte subsets, cytokines and other laboratory markers were compared between the groups.

RESULTS

The frequency of proposed risk factors for CAM was diabetes mellitus (77%), recent history of steroid use (69%) and hypoxia during COVID-19 infection (52%). Iron metabolism was dysregulated in CAM patients with low TIBC and total iron. Further, CAM was accompanied with lymphopenia with drastic reduction in B cell counts; however, plasmablasts were not altered. Further, CAM patients had low immunoglobulin levels and antibodies specific to mucor peptide did not increase in CAM suggesting dysfunction in B-cell response. There was increase in activated effector cytotoxic CD8 T cells and NK cells in CAM compared with COVID-19 infection and healthy controls. Among T helper cells, Tregs were reduced and Th-1 frequency was increased in CAM compared with COVID-19 infection. A distinct cytokine signature was evident in CAM with increase in IL-1β, IFN-γ, IL-6, IL-22, IL-17A, IL-10, IL-2, IL-8, IL-7, IL-21 and GM-CSF.

CONCLUSION

This is the first study on immunophenotyping in CAM suggesting the need for long-term monitoring of B-cell function after SARS-CoV-2 in patients with dysregulated glycaemic control and the possible benefit of therapeutic supplementation with intravenous immunoglobulins in CAM.

The mucormycosis and stroke: The learning curve during the second COVID-19 pandemic

BACKGROUND

The Angio-invasive Rhino-orbito-cerebral mucormycosis (ROCM) producing strokes is a less explored entity. Our hospital, a stroke-ready one, had an opportunity to manage mucormycosis when it was identified as the nodal center for mucormycosis management. We are sharing our experiences and mistakes in managing the cerebrovascular manifestations of ROCM.

METHODS

We conducted a prospective observational study during the second wave of the COVID-19 pandemic from 1st May 2021 to 30th September 2021, where consecutive patients aged more than 18 years with microbiologically confirmed cases of ROCM were included. Clinical details (timing of stroke onset after ROCM symptoms, GCS, NIHSS), imaging findings (ASPECTS, the territory of stroke, the pattern of infarct, hemorrhagic transformation, cavernous sinus thrombosis), angiogram findings, management details (IV thrombolysis), and outcomes (mRS at discharge and duration of hospital stay) were documented. We also compared the demographics, clinical features (NIHSS), radiological findings, treatment details, duration of hospital stay, and functional outcome at the discharge of the ROCM stroke patients with stroke patients without ROCM.

RESULTS

Stroke developed in 42% of patients with ROCM, predominantly anterior circulation border zone ischemic infarcts. Strokes occurred after a median of five days from the onset of ROCM symptoms. The most common vessel involved was the ophthalmic artery, followed by the cavernous ICA. We could not thrombolyse ROCM stroke patients. ROCM patients who developed stroke compared with patients without stroke had a more infiltrative fungal infection and higher inflammatory markers. Mucormycosis associated stroke patients had higher in-hospital mortality and poor functional outcomes.

T CONCLUSION

Due to delayed recognition of stroke symptoms, none received reperfusion strategies, leading to poor functional outcomes. For early stroke detection, ROCM cases need frequent monitoring and education of patients and their relatives about the ALS acronym (loss of ambulation, limb weakness, and loss of speech).

Is mucormycosis the end? A comprehensive management of orbit in COVID associated rhino-orbital-cerebral mucormycosis: preserving the salvageable

BACKGROUND

Rhino-orbital-cerebral mucor mycosis (ROCM) is a relatively rare opportunistic infection caused by the Mucorales species. While ROCM suggests involvement of the paranasal sinuses, orbit and brain ROM (rhino-orbital-Mucormycosis) stands for the fungal invasion in sinuses and orbit sans cerebral involvement. In India with the outbreak of the second COVID wave and the delta variant of the virus, there has been a steep increase in this opportunistic fulminant fungal infection, named COVID-associated Mucor mycosis (CAM). The most critical question in orbital management is when to go ahead with an exenteration. Our study aims to design a pertinent minimal invasive surgical protocol for surgeons to manage such cases based on our surgical experience and mitigate the need for exenteration and save the eyes wherever possible.

METHODS

The study is a retrospective analysis of patients of ROM with and without brain involvement, who underwent minimal surgical management between March 2021 to March 2022 along with their follow-up.

RESULTS

There were 184 eyes of 148 patients diagnosed with CAM. The mean age was 51.7 years with a male predominance of 103 (70%). All patients developed ROM following the COVID-19 infection and the duration between diagnosis of COVID-19 and ROM was 36 ± 23 days. 18 cases (12%) were bilateral. 76 eyes (41%) had no vision at the presentation. Imaging revealed paranasal sinus involvement (100%), orbital apex involvement (61%), cavernous sinus involvement (53%), and central nervous system (CNS) involvement (47%). All the patients (100%) were treated with systemic Liposomal amphotericin-B and sinus debridement. Endoscopic debridement of the orbital disease was performed in 45 (30.4%) cases, 15(8.1%) eyes underwent exenteration and were later rehabilitated with a customized ocular prosthesis, 103 (56%) eyes underwent transcutaneous retrobulbar amphotericin-B. At a mean follow-up of 13.1 months; the complete resolution was seen in 25 (17%) cases, the residual stable lesion was seen in 77(52%) of the cases and new lesions were developed in 13(9%) of the cases. Mortality was seen in 33 (22%) patients and all of them had CNS involvement.

CONCLUSIONS

Systemic and protocol-based management can save the life and salvage the eyes.

Rapid Cytological Diagnosis With Evaluation of Pre- and Post-Therapeutic Fungal Morphological Characteristics in Mucormycosis

Background

Mucormycosis necessitates rapid diagnosis and treatment. Microscopy and culture have been considered the gold standard for diagnosis but both take time of 3 - 5 days. KOH mount is another method for fungal identification that takes 1 - 2 h, but it has its own limitations. This study evaluated crush smear as a means of rapid cytological diagnosis.

Methods

Biopsy tissue (pre-treatment) from clinically suspicious mucormycosis patients (n = 52) was received in normal saline and crush/imprint smears were prepared; the remaining tissue was processed as routine biopsy specimen. After the rapid initial cytological identification, the patients were managed according to the standard clinical protocol. Random post-therapeutic biopsy samples of some of these patients (n = 19) were also obtained and again evaluated cytologically.

Results

Crush smears showed sensitivity/specificity of 77.7%/75.0% with histopathology and 72.2%/62.5% with culture, respectively, while KOH mount had values of 71.4%/70.5% with histopathology and 79.3%/69.5% with culture, respectively. Degenerative fungal morphological characteristics and cellular inflammatory infiltrate (predominantly neutrophilic) in the vicinity of fungal hyphae were compared in pre- and post-treatment groups, and we found a statistically significant difference (P < 0.05) between them.

Conclusion

Our preliminary results suggest that crush smear cytology is a simple, rapid, cost-effective and easily available method for diagnosing mucormycosis. Moreover, crush smears also demonstrated morphological alteration in hyphal structure and accompanying immune cell infiltration which may provide valuable insights into mechanism of therapy/host immune response against fungal pathogen.

T cell responses to control fungal infection in an immunological memory lens

In recent years, fungal vaccine research emanated significant findings in the field of antifungal T-cell immunity. The generation of effector T cells is essential to combat many mucosal and systemic fungal infections. The development of antifungal memory T cells is integral for controlling or preventing fungal infections, and understanding the factors, regulators, and modifiers that dictate the generation of such T cells is necessary. Despite the deficiency in the clear understanding of antifungal memory T-cell longevity and attributes, in this review, we will compile some of the existing literature on antifungal T-cell immunity in the context of memory T-cell development against fungal infections.

Invasive Mucormycosis and Aspergillosis Coinfection Associated with Post-COVID-19 Pneumonia in a Tertiary Care Hospital

Acute invasive fungal rhinosinusitis is a rare infection primarily affecting patients with co-morbidities like immunosuppression and poorly controlled diabetes. Mucormycosis is increasingly being reported in patients with SARS-CoV-2 (COVID-19). However, reports of coinfection of aspergillosis and mucormycosis involving nose, paranasal sinuses, orbit, and brain are rare in literature. We aimed to evaluate the patient demographics, clinical presentation, and management of cases presenting with mixed infection. We carried out retrospective analysis of 12 patients with confirmed diagnosis of mixed invasive fungal infections post-COVID-19 disease out of 70 cases of COVID-19-associated mucormycosis (CAM) presenting to a tertiary-level hospital in North India from May to June 2021. All patients had diabetes mellitus; the mean age was 48 years. The common presenting features were headache, nasal congestion, palatal ulcer, and vision loss accompanied by facial pain and swelling. Two patients developed cerebral abscess during the course of treatment; three patients had concurrent COVID-19 pneumonia. All patients received systemic liposomal amphotericin B and serial surgical debridements. The overall mortality rate was 16.7%. Our study demonstrates that mucormycosis and aspergillosis are angioinvasive mycoses that are clinically and radiologically identical. KOH direct mount of clinical sample showing septate hyphae should be extensively searched for aseptate hyphae after digestion and clearing of the tissue. A high index of suspicion of mixed infection post-COVID-19 and early initiation of liposomal amphotericin B followed by prompt surgical intervention can reduce the overall morbidity and mortality among patients with this condition.

Rhinocerebral mucormycosis in a diabetes type 2 patient: A fatal case report from northern Tanzania

Mucormycosis is an acute and aggressive fungal infection usually, but not exclusively, occurring in immunocompromised individuals. Lack of knowledge and awareness in developing countries hinders timely management. This case highlights the importance of a prompt index of suspicion for the timely and aggressive intervention of mucormycosis to the Tanzanian community. We report a case of fatal rhino-orbital-cerebral mucormycosis in a diabetic patient presenting at a tertiary hospital in the Kilimanjaro region, Tanzania. Nasal deformity, proptosis, chemosis and left-sided hemiplegia were evident on physical examination. Nasoendoscopy revealed extensive necrosis of the nasal septum, inferior turbinate and involvement of the frontal recess. Computed tomography and magnetic resonance imaging of the paranasal sinuses and head revealed necrosis and ischemic changes due to fungal invasion. The patient deceased due to intracranial complications of advanced fungal invasion. Late presentation and unacquainted with mucormycosis our patient had an unfavourable outcome. Early diagnosis, extensive surgical debridement and a multidisciplinary approach to treatment are of the essence in favour of a better prognosis.

Blockade of the PD-1/PD-L1 Immune Checkpoint Pathway Improves Infection Outcomes and Enhances Fungicidal Host Defense in a Murine Model of Invasive Pulmonary Mucormycosis

Anecdotal clinical reports suggested a benefit of adjunct immune checkpoint inhibitors (ICIs) to treat invasive mucormycosis. However, proof-of-concept data in animal models and mechanistic insights into the effects of ICIs on host defense against Mucorales are lacking. Therefore, we studied the effects of PD-1 and PD-L1 inhibitors (4 doses of 250 µg/kg) on outcomes and immunopathology of invasive pulmonary mucormycosis (IPM) in cyclophosphamide- and cortisone acetate-immunosuppressed mice. Rhizopus arrhizus-infected mice receiving either of the ICI treatments had significantly improved survival, less morbidity, and lower fungal burden compared to isotype-treated infected mice. While early improvement of morbidity/mortality was comparable between the ICI treatments, anti-PD-L1 provided more consistent sustained protection through day 7 post-infection than anti-PD-1. Both ICIs enhanced the fungicidal activity of ex-vivo splenocytes and effectively counteracted T-cell exhaustion; however, macrophages of ICI-treated mice showed compensatory upregulation of other checkpoint markers. Anti-PD-1 elicited stronger pulmonary release of proinflammatory cytokines and chemokines than anti-PD-L1, but also induced cytokines associated with potentially unfavorable type 2 T-helper-cell and regulatory T-cell responses. Although no signs of hyperinflammatory toxicity were observed, mice with IPM receiving ICIs, particularly anti-PD-1, had elevated serum levels of IL-6, a cytokine linked to ICI toxicities. Altogether, inhibition of the PD-1/PD-L1 pathway improved clinical outcomes of IPM in immunosuppressed mice, even without concomitant antifungals. PD-L1 inhibition yielded more favorable immune responses and more consistent protection from IPM-associated morbidity and mortality than PD-1 blockade. Future dose-effect studies are needed to define the “sweet spot” between ICI-induced augmentation of antifungal immunity and potential immunotoxicities.

Risks of mucormycosis in the current Covid-19 pandemic: a clinical challenge in both immunocompromised and immunocompetent patients

Mucormycosis, also called "Black Fungus", is a new cause for worry in the current Coronavirus disease 2019 (covid-19) pandemic. Mucormycosis is devasting due to its high rate of morbidity and mortality which is a great cause of concern. Mucormycosis, in general, affects immunocompromised patients including diabetic, people with malignancies, organ and stem cell transplants and people affected with pandemic diseases like covid-19. Diagnosis of Mucormycosis is often delayed either due to clinical complications or misdiagnosed as symptoms of other diseases, especially covid-19. This could delay the treatment protocol which results in the failure of treatment. Mortality rate due to secondary infections in covid-19 patients with uncontrolled diabetics and who are on steroid therapy can soon reach 100% if diagnosis and treatment doesn't happen on timely basis. Risk of Mucormycosis is not just in immunosuppressed patients, but immunocompetent people with late diagnosis are also prone to infection. In view of this, we present a comprehensive review on risks of Mucormycosis in immunocompromised and immunocompetent patients highlighting the epidemiology, forms of Mucormycosis, immune response against Mucorales, difficulties in diagnosis and challenges in treatment of Mucormycosis, with emphasis on covid-19 associated Mucormycosis. Importantly, we have discussed the precautions and care to effectively manage Mucormycosis in immunocompromised and immunocompetent patients. Thus, current review helps clinicians in understanding various risk factors in both immunocompromised (especially covid-19 patients) and immunocompetent patients which is critical in managing Mucormycosis in current covid-19 pandemic.

Mucormycosis (black fungus) ensuing COVID-19 and comorbidity meets - Magnifying global pandemic grieve and catastrophe begins

Post COVID-19, mucormycosis occurred after the SARS-CoV-2 has rampaged the human population and is a scorching problem among the pandemic globally, particularly among Asian countries. Invasive mucormycosis has been extensively reported from mild to severe COVID-19 survivors. The robust predisposing factor seems to be uncontrolled diabetes mellitus, comorbidity and immunosuppression acquired through steroid therapy. The prime susceptive reason for the increase of mucormycosis cases is elevated iron levels in the serum of the COVID survivors. A panoramic understanding of the infection has been elucidated based on clinical manifestation, genetic and non- genetic mechanisms of steroid drug administration, biochemical pathways and immune modulated receptor associations. This review lime-lights and addresses the "What", "Why", "How" and "When" about the COVID-19 associated mucormycosis (CAM) in a comprehensive manner with a pure intention to bring about awareness to the common public as the cases are inevitably and exponentially increasing in India and global countries as well. The article also unearthed the pathogenesis of mucormycosis and its association with the COVID-19 sequela, the plausible routes of entry, diagnosis and counter remedies to keep the infection at bay. Cohorts of case reports were analysed to spotlight the link between the pandemic COVID-19 and the nightmare-mucormycosis.

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.

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.

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.

Microbiological and Molecular Diagnosis of Mucormycosis: From Old to New

Members of the order Mucorales may cause severe invasive fungal infections (mucormycosis) in immune-compromised and otherwise ill patients. Diagnosis of Mucorales infections and discrimination from other filamentous fungi are crucial for correct management. Here, we present an overview of current state-of-the-art mucormycosis diagnoses, with a focus on recent developments in the molecular field. Classical diagnostic methods comprise histology/microscopy as well as culture and are still the gold standard. Newer molecular methods are evolving quickly and display great potential in early diagnosis, although standardization is still missing. Among them, quantitative PCR assays with or without melt curve analysis are most widely used to detect fungal DNA in clinical samples. Depending on the respective assay, sequencing of the resulting PCR product can be necessary for genus or even species identification. Further, DNA-based methods include microarrays and PCR-ESI-MS. However, general laboratory standards are still in development, meaning that molecular methods are currently limited to add-on analytics to culture and microscopy.

[Mucormycosis: Current and future management perspective]

Infections caused by mucorales, with an increasing incidence after candidiasis and aspergillosis, are characterized by the fast angioinvasion of blood vessels and invasion of neighboring organs or structures. Mucorales most commonly cause rhinocerebral, pulmonary, cutaneous, digestive or disseminated infections, and their spread is favored by certain underlying diseases (diabetes, kidney failure) and risk factors (neutropenia, immunosuppression, iron overload). These infections have a high mortality rate, over 40% in many series, and the key to their cure depends on both an early diagnosis and an antifungal treatment, associated in most cases with extensive surgical debridement and other adjunctive therapies. Currently, there are international guidelines, not only local ones, for the management of mucormycosis, in which it is considered by consensus and with a strong recommendation that first-line treatment with high-dose liposomal amphotericin B is the best choice. The combined antifungal treatment of polyene agents with triazoles or candins remains in open debate.

Cutaneous and subcutaneous fungal infections: recent developments on host-fungus interactions

The incidence of skin fungal infections is increasing at an alarming rate worldwide, presenting a major challenge to health professionals. Cutaneous and subcutaneous fungal infections are caused by pathogenic or opportunistic organisms varying from mold, yeasts, to dimorphic fungi. Recently, skin fungal have been increasingly reported and studied, giving rise to crucial breakthroughs in etiology and pathogenesis. This review aims to summarize recent insights into the clinical and etiological characteristics of common skin fungal infections according to different fungal species, as well as remarkable advances in the immune mechanisms. We hope it will be helpful to understand these diverse skin fungal infections, and bring about the latest developments that may facilitate novel diagnostic and therapeutic approaches to improve the outcomes in these patients.

Evaluation of Sex Differences in Murine Diabetic Ketoacidosis and Neutropenic Models of Invasive Mucormycosis

There is increased concern that the quality, generalizability and reproducibility of biomedical research can be influenced by the sex of animals used. We studied the differences between male and female mice in response to invasive pulmonary mucormycosis including susceptibility to infection, host immune reaction and responses to antifungal therapy. We used diabetic ketoacidotic (DKA) or neutropenic mice infected with either Rhizopus delemar or Mucor circinelloides. The only difference detected was that when DKA mice were infected with M. circinelloides, female mice were more resistant to infection than male mice (median survival time of 5 vs. 2 days for female and male mice, respectively). However, a 100% lethality was detected among infected animals of both sexes. Treatment with either liposomal amphotericin B (L-AMB) or posaconazole (POSA) protected mice from infection and eliminated the difference seen between infected but untreated female and male mice. Treatment with L-AMB consistently outperformed POSA in prolonging survival and reducing tissue fungal burden of DKA and neutropenic mice infected with R. delemar or M. circinelloides, in both mouse sexes. While little difference was detected in cytokine levels among both sexes, mucormycosis infection in the DKA mouse model induced more inflammatory cytokines/chemokines involved in neutrophil (CXCL1) and macrophage (CXCL2) recruitment vs. uninfected mice. As expected, this inflammatory response was reduced in the neutropenic mouse model. Our studies show that there are few differences between female and male DKA or neutropenic mice infected with mucormycosis with no effect on the outcome of treatment or host immune response.