Intracranial complications of mucormycosis: an experimental model and clinical review

Precision Detection of Fungal Co-Infections for Enhanced COVID-19 Treatment Strategies Using FESEM Imaging

The treatment of fungal infections presents significant challenges due to the lack of standardized diagnostic procedures, a restricted range of antifungal treatments, and the risk of harmful interactions between antifungal medications and the immunosuppressive drugs used in anti-inflammatory treatment for critically ill patients with COVID-19. Mucormycosis and aspergillosis are the primary invasive fungal infections in patients with severe COVID-19, occurring singly or in combination. Histopathological examination is a vital diagnostic technique that details the presence and invasion of fungi within tissues and blood vessels, and the body's response to the infection. However, the pathology report omits information on the most common fungi associated with the observed morphology, as well as other potential fungi and parasites that ought to be included in the differential diagnosis. This research marks significance in diagnosing fungal infections, such as mucormycosis and aspergillosis associated to COVID-19 by field emission scanning electron microscopy (FESEM) imaging to examine unstained histopathology slides, allowing for a detailed morphological analysis of the fungus. FESEM provides an unprecedented resolution and detail, surpassing traditional Hematoxylin & Eosin (H&E) and Grocott's Methenamine Silver (GMS) staining methods in identifying and differentiating dual fungal infections and diverse fungal species. The findings underscore the critical need for individualized treatment plans for patients severely affected by COVID-19 and compounded by secondary fungal infections. The high-magnification micrographs reveal specific fungal morphology and reproductive patterns. Current treatment protocols largely depend on broad-spectrum antifungal therapies. However this FESEM guided diagnostic approach can help in targeted patient specific anti fungal therapies. Such precision could lead to more effective early interventions, addressing the complex management required for severe COVID-19 cases with coexisting fungal infections. This approach significantly advances disease management and patient recovery, advocating for personalized, precision medicine in tackling this multifaceted clinical challenge.

Graphical Abstract

Experimental Models to Study the Pathogenesis and Treatment of Mucormycosis

Mucormycosis presents a formidable challenge to clinicians and researchers. Animal models are an essential part of the effort to decipher the pathogenesis of mucormycosis and to develop novel pharmacotherapeutics against it. Diverse model systems have been established, using a range of animal hosts, immune and metabolic perturbations, and infection routes. An understanding of the characteristics, strengths, and drawbacks of these models is needed to optimize their use for specific research aims.

COVID-19 associated mold infections: Review of COVID-19 associated pulmonary aspergillosis and mucormycosis

COVID-19-associated mold infection (CAMI) is defined as development of mold infections in COVID-19 patients. Co-pathogenesis of viral and fungal infections include the disruption of tissue barrier following SARS CoV-2 infection with the damage in the alveolar space, respiratory epithelium and endothelium injury and overwhelming inflammation and immune dysregulation during severe COVID-19. Other predisposing risk factors permissive to fungal infections during COVID-19 include the administration of immune modulators such as corticosteroids and IL-6 antagonist. COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated mucormycosis (CAM) is increasingly reported during the COVID-19 pandemic. CAPA usually developed within the first month of COVID infection, and CAM frequently arose 10-15 days post diagnosis of COVID-19. Diagnosis is challenging and often indistinguishable during the cytokine storm in COVID-19, and several diagnostic criteria have been proposed. Development of CAPA and CAM is associated with a high mortality despiteappropriate anti-mold therapy. Both isavuconazole and amphotericin B can be used for treatment of CAPA and CAM; voriconazole is the primary agent for CAPA and posaconazole is an alternative for CAM. Aggressive surgery is recommended for CAM to improve patient survival. A high index of suspicion and timely and appropriate treatment is crucial to improve patient outcome.

Coincidence or reality behind Mucormycosis, diabetes mellitus and Covid-19 association: A systematic review

Mucormycosis is a rare but life-threatening disease with high morbidity and mortality and is difficult to diagnose. Mucormycosis, is a severe but rare fungal infection caused by a group of molds called mucormycetes. Diabetes, use of corticosteroids, metabolic/diabetic acidosis and Covid-19 mediated immunosuppression are reported in more than 70% of cases in mucormycosis patients. Coexisting mucormycosis, Covid-19 along with diabetes mellitus increase the likelihood of mortality. Despite its occurrence since the beginning of the pandemic, there are still unanswered concerns regarding the origin of this fungal infection and mortality rate and/or relation with diabetic patients. In this review, we describe the detailed view of causative pathogens responsible for mucormycosis, diabetes mellitus and Covid-19 association along with the morbidity cases during the latest Covid-19 crisis. In the case of mucormycosis diagnosis, imaging, histopathological confirmation, fungal culture and molecular identification methods should be considered. Once mucormycosis is diagnosed, a combined treating method consisting of antifungals administration like amphotericin B, surgical intervention is needed for the reversal of the underlying condition. Early detection of this potentially life-threatening infection and timely care is needed in lowering mortality rates.

Case Report: Diagnostic Value of Metagenomics Next Generation Sequencing in Intracranial Infection Caused by Mucor

mNGS(metagenomics Next Generation Sequencing), as a novel culture-independent approach, demonstrated the capability of rapid, sensitive, and accurate pathogen identification. At present, there have been many case reports about the use of mNGS to assist in the diagnosis of bacterial, fungal, viral and parasitic infections and to guide clinicians to determine appropriate treatment. However, the clinical understanding of this technique is not comprehensive, and the experience of using it is relatively limited. We reported a 53-year-old man who was admitted to hospital with a high fever and headache. His inflammatory biomarkers were markedly elevated. Based on the clinical presentation, He was initially diagnosed as having an intracranial infection of unknown etiology and received empirical antibiotics and systemic supportive treatment. But these did not relieve his symptoms. Both the blood and CSF specimens were examined using traditional culture, serological testing, and mNGS. Traditional culture and serological testing produced negative results, while the mNGS revealed the presence of a potential pathogen, mucor, in the CSF specimen. Then targeted antifungal treatment was selected quickly and his temperature gradually returned to normal. Thus, we report the case in which mNGS was an auxiliary method to diagnose mucormycosis, and discuss this case in combination with relevant literature, in order to improve the clinical cognition of this technology.

Animal Models to Study Mucormycosis

Mucormycosis is a rare but often fatal or debilitating infection caused by a diverse group of fungi. Animal models have been crucial in advancing our knowledge of mechanisms influencing the pathogenesis of mucormycoses, and to evaluate therapeutic strategies. This review describes the animal models established for mucormycosis, summarizes how they have been applied to study mucormycoses, and discusses the advantages and limitations of the different model systems.

Treatment of Rhinocerebral Mucormycosis by Combination of Endoscopic Sinus Debridement and Amphotericin B

Rhinocerebral mucormycosis (RCM) is an aggressive fungal infection with a high mortality rate. It frequently develops in patients with uncontrolled diabetes mellitus or immunocompromised patients. RCM typically presents in a rapidly fulminant manner with headache, fever, mucosal necrosis, and ophthalmic symptoms. Although the definitive diagnosis is achieved by histopathological examination, computed tomography (CT) scanning and magnetic resonance (MR) are the best imaging procedures in early diagnosis to assess the extent of the disease.

Ectopic Prolactinoma Presenting as Bacterial Meningitis: A Diagnostic Conundrum

BACKGROUND

Prolactinomas may rarely present with meningitis and cerebrospinal fluid (CSF) rhinorrhea secondary to erosion of the wall of the sella turcica. It is even more uncommon for this abnormal communication to be caused by an ectopic prolactinoma arising from the sphenoid sinus and eroding into the sella. This atypical growth pattern makes diagnosis very difficult because there may be no displacement of the normal pituitary gland. The first reported case of a patient with an ectopic prolactinoma originating within the sphenoid sinus presenting primarily with meningitis is presented, and the management strategy and surgical and nonsurgical treatment options are discussed.

CASE DESCRIPTION

A 48-year-old woman presented with confusion, low-pressure headache, and fever. A lumbar puncture revealed Streptococcus pneumoniae meningitis, and she was placed on intravenous penicillin G. After initiation of antibiotics, she noticed salty tasting postnasal fluid leakage. Imaging was remarkable for bony erosion of the sphenoid sinus wall by a soft tissue mass growing from within the sinus, with no disruption of the normal pituitary gland. A biopsy was then performed with an endoscopic transnasal transsphenoidal approach, and the CSF leak was repaired with a pedicled nasoseptal flap. The final pathology was prolactinoma, and she was placed on cabergoline.

CONCLUSIONS

Ectopic prolactinomas may rarely present as meningitis secondary to retrograde transmission of bacteria through a bony defect in the sphenoid sinus, and must be included in the differential diagnosis of any sphenoid sinus mass. Management should first address the infection, followed by surgical repair of the bony defect.

Rhinocerebral mucormycosis in a 5-month heart transplant recipient

Mucormycosis is an opportunistic acute fungal infection with a high mortality rate seen in immunocompromised patients. It is extremely rare in heart transplant recipients. Rhinocerebral mucormycosis (RM) is the most frequently observed presentation. We report a case of RM in a heart transplant recipient 5-month after the procedure, with a fatal outcome.

Fatal rhinocerebral mucormycosis with intracavernous carotid aneurysm and thrombosis: a late complication of transsphenoidal surgery?

Mucormycosis is a rare opportunistic fungal infection. Rhinocerebral form of the disease mainly affects diabetic or immunocompromised patients. Mucormycosis have specific tropism for blood vessels leading to mucorthrombosis and less often to mycotic aneurysms. We report on a patient initially presenting with a severe sphenoid sinusopathy, who progressively evolved to cavernous sinus syndrome, internal carotid aneurysm followed by spontaneous thrombosis, chronic meningitis and ultimately fatal hypertensive hydrocephalus. Necropsy revealed a purulent infiltrate containing thin-walled, aseptate, right-angle branching, hyphae consistent with mucormycosis. His only relevant previous medical history was a transsphenoidal surgery for pituitary macroadenoma 21 years before. We hypothesize that post-surgical mucosal changes in the sphenoid sinus have been a favoring factor for delayed and invasive mucor infection.

Pathogenesis of mucormycosis

Mucormycosis is a life-threatening infection that occurs in patients who are immunocompromised because of diabetic ketoacidosis, neutropenia, organ transplantation, and/or increased serum levels of available iron. Because of the increasing prevalence of diabetes mellitus, cancer, and organ transplantation, the number of patients at risk for this deadly infection is increasing. Despite aggressive therapy, which includes disfiguring surgical debridement and frequently adjunctive toxic antifungal therapy, the overall mortality rate is high. New strategies to prevent and treat mucormycosis are urgently needed. Understanding the pathogenesis of mucormycosis and the host response to invading hyphae ultimately will provide targets for novel therapeutic interventions. In this supplement, we review the current knowledge about the virulence traits used by the most common etiologic agent of mucormycosis, Rhizopus oryzae. Because patients with elevated serum levels of available iron are uniquely susceptible to mucormycosis and these infections are highly angioinvasive, emphasis is placed on the ability of the organism to acquire iron from the host and on its interactions with endothelial cells lining blood vessels. Several promising therapeutic strategies in preclinical stages are identified.

Rhinocerebral mucormycosis complicated by internal carotid artery thrombosis in a pediatric patient with type 1 diabetes mellitus: a case report and review of the literature

OBJECTIVE

To illustrate that rapid diagnosis and aggressive treatment of rhinocerebral mucormycosis with internal carotid artery occlusion in a pediatric patient can prevent mortality and significant morbidity.

RESEARCH DESIGNS AND METHODS

Rhinocerebral mucormycosis infrequently occurs in the pediatric population, and when it involves thrombosis of an internal carotid artery, it has been almost uniformly fatal. We present an 8-yr-old girl with type 1 diabetes mellitus who has survived such an infection for 2 yr, and who has minimal residual morbidity. We believe she is the youngest patient to survive rhinocerebral mucormycosis complicated by internal carotid artery and cavernous sinus thromboses. She has survived with an intensive regimen including aggressive surgical debridement, amphotericin B, rigorous glucose control, hyperbaric oxygen therapy, interferon-gamma, posaconazole (an experimental antifungal), and granulocyte-macrophage colony-stimulating factor.

CONCLUSIONS

This article illustrates the importance of prompt recognition and aggressive treatment of fungal infection in patients with diabetes. Additionally, it emphasizes that such treatment can have an excellent outcome, and mortality and significant morbidity can be avoided. Finally, we provide a review of the literature regarding mucormycosis infections and treatment options.

Rhinocerebral mucormycosis: An analysis of probable mode of spread and its implication in an early diagnosis and treatment

The study was done in two parts:Analysis of CT scan findings of 17 cases of mucormycosis to determine paranasal sinus, orbital and intra-cranial involvement.Cadaveric dissections of the ethmoid complex anatomy to correlate the probable mode of spread. Ethmoidal sinus was found to be the most commonly involved. The disease probably appears first here, spreads to orbit through the lamina papyracea and then through the retro-orbital region, intra-cranially. Our aim would be to diagnose the disease at the stage of ethmoid involvement. In immuno-compromised patients, if headache, peri- or retro-orbital pain or blood stained nasal discharge occur; a CT scan of the paranasal sinuses and a nasal endoscopy with biopsy from anterior ethmoids, if this area shows pathology then CT scan must be performed. If this is positive for mucormycosis, surgical debridement of the involved sinuses is to be done and Amphotericin B as intra-venous infusion and treatment of underlying condition is started.

Bull's-eye cutaneous infarct of zygomycosis: A bedside diagnosis confirmed by touch preparation

We report an immunocompromised woman with chronic lymphocytic leukemia who developed cutaneous zygomycosis at the site of an arterial line. The initial lesion resembled a bulls-eye. Bull's-eye lesions of zygomycosis have been reported twice before. Recognition of this sign may allow the dermatologist to make a rapid presumptive diagnosis and initiate treatment for this life-threatening infection.

Current perspectives on ophthalmic mycoses

Fungi may infect the cornea, orbit and other ocular structures. Species of Fusarium, Aspergillus, Candida, dematiaceous fungi, and Scedosporium predominate. Diagnosis is aided by recognition of typical clinical features and by direct microscopic detection of fungi in scrapes, biopsy specimens, and other samples. Culture confirms the diagnosis. Histopathological, immunohistochemical, or DNA-based tests may also be needed. Pathogenesis involves agent (invasiveness, toxigenicity) and host factors. Specific antifungal therapy is instituted as soon as the diagnosis is made. Amphotericin B by various routes is the mainstay of treatment for life-threatening and severe ophthalmic mycoses. Topical natamycin is usually the first choice for filamentous fungal keratitis, and topical amphotericin B is the first choice for yeast keratitis. Increasingly, the triazoles itraconazole and fluconazole are being evaluated as therapeutic options in ophthalmic mycoses. Medical therapy alone does not usually suffice for invasive fungal orbital infections, scleritis, and keratitis due to Fusarium spp., Lasiodiplodia theobromae, and Pythium insidiosum. Surgical debridement is essential in orbital infections, while various surgical procedures may be required for other infections not responding to medical therapy. Corticosteroids are contraindicated in most ophthalmic mycoses; therefore, other methods are being sought to control inflammatory tissue damage. Fungal infections following ophthalmic surgical procedures, in patients with AIDS, and due to use of various ocular biomaterials are unique subsets of ophthalmic mycoses. Future research needs to focus on the development of rapid, species-specific diagnostic aids, broad-spectrum fungicidal compounds that are active by various routes, and therapeutic modalities which curtail the harmful effects of fungus- and host tissue-derived factors.

Animal models of zygomycosis--Absidia, Rhizopus, Rhizomucor, and Cunninghamella

Infections caused by zygomycetes, which have been increasing in recent years, are known for their difficulty of diagnosis and treatment. Because little is known about this fungus and its infection, vigorous research is now in serious demand. As in many other systemic mycoses, animal model studies are essential in the investigation of zygomycosis, particularly for the study of pathogenesis, diagnosis and treatment. Unfortunately, such studies have been limited when compared with those of aspergillosis. To help investigating the disease, here in this review article, the profile of human zygomycosis is briefly described, followed by a review of the heretofore used animal models of zygomycosis. Among clinically important zygomycetes causing human infection, animal models are available for Absidia corymbifera, Rhizopus oryzae, R. microsporus var. rhizopodiformis, Rhizomucor pusillus and Cunninghamella bertholletiae. Mice are the most commonly used animals, but models using guinea pigs and rabbits are also available. Pretreatment of animals with cyclophosphamide, corticosteroid, alloxan or streptozocine is frequently done to create an immunocompromised state. Treatment with desferrioxamine, an iron chelator, is also used to make animal models. In terms of the route of infection, the airborne route is used for pathophysiological studies in pulmonary infection models, but sometimes intravenous injection is preferred, particularly for antifungal drug studies. When pathophysiological analysis is the purpose of the study, the animals must be cautiously examined both histopathologically and mycologically. For the most part, zygomycosis model studies can be performed in a similar manner to those of aspergillosis. However, Aspergillus spp. and zygomycetes are completely different fungi, and researchers should be aware of the specific, critical aspects when handling zygomycosis models, such as homogenization of infected organs and staining of pathological samples.

Rhinocerebral mucormycosis in the era of lipid-based amphotericin B: case report and literature review

Rhinocerebral mucormycosis (RCM) is an invasive fungal infection that necessitates, in most cases, aggressive surgical debridement and high cumulative, often nephrotoxic doses of amphotericin B. A 50-year-old woman with RCM was treated successfully with amphotericin B lipid complex as primary therapy. The patient previously had displayed progressive intracranial involvement and rising serum creatinine levels while receiving the conventional (nonlipid) form of amphotericin B. A literature review identified only a few cases where systemic antifungal therapy was administered, with minimal or no surgery. Our case further supports that amphotericin B lipid complex can be used as primary therapy in selected patients with RCM, without the need for surgical exenteration.

Hyperbaric oxygen as an adjunct in zygomycosis: randomized controlled trial in a murine model

Zygomycosis was induced by injecting CD-1 mice with 5 mg of intraperitoneal deferoxamine and then 10(6) CFU of intravenous and intrasinus Rhizopus arrhizus. The addition of hyperbaric oxygen (2.0 atm absolute twice daily) to amphotericin B did not improve survival over that achieved with amphotericin B and placebo air treatments.

Rhinosinusitis in transplant patients

The control of perioperative infection has become more important to increase the success rate of organ transplantation. Thorough examination for occult infection prior to transplantation, careful postoperative monitoring and prompt treatment of infections are required. We reviewed the medical records of 278 patients who received organ transplantation over 4 years and analysed the clinical course of rhinosinusitis during the pre- and post-transplantation period. Thirty-two (11.5%) patients had rhinosinusitis. Nineteen were detected during preoperative examination and 13 were postoperative. Sinus surgery was performed in nine patients before organ transplantation. Ten out of 13 patients who had rhinosinusitis detected after transplantation required sinus surgery and three patients had invasive fungal infections. In the immunocompromised host, the clinical presentation of rhinosinusitis may be subtle, but the subsequent clinical course may be fulminant or even fatal. If the transplant recipient has unexplained fever or any nasal symptom, thorough evaluation with a high index of suspicion and prompt management are required.

Rhinocerebral zygomycosis in a patient with acute lymphoblastic leukemia

We report a case of a 28-year-old man with acute lymphoblastic leukemia who developed rhinocerebral zygomycosis during induction chemotherapy. This life-threatening fungal infection is an infrequent cause of neutropenic fever, and is occasionally found in patients with leukemia and lymphoma, or patients with severely compromised defence mechanisms due to other diseases. It is caused by moulds belonging to the Mucoraceae family, and is characterized by local destruction of the affected organ. In our patient, the infection spread from the paranasal sinuses to the right orbit, destroyed intraorbital structures and resulted in blindness within days. Biopsy from the right maxillary sinus was performed and mucormycosis was suspected through microscopic examination. Culture of the resected specimen identified Rhizopus arrhizus as the causing agent. Treatment of zygomycosis should consist of radical surgical debridement of the infected tissue, together with intensive broad-spectrum antimycotic therapy with amphotericin B. What could be learned from this case is, that aggressive approaches to identify the cause of infection is necessary, and that aggressive treatment strategies are inevitable to overcome the infection. Furthermore, treatment of the underlying disease should be continued as soon as possible.

Zygomycetes in human disease

The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

Zygomycetes in human disease

The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

Long-term survival of a patient with invasive cranial base rhinocerebral mucormycosis treated with combined endovascular, surgical, and medical therapies: case report

OBJECTIVE

Rhinocerebral mucormycosis is a clinical syndrome resulting from an opportunistic infection caused by a fungus of the order Mucorales. The prognosis of rhinocerebral mucormycosis, once considered uniformly fatal, remains poor. Even with early diagnosis and aggressive surgical and medical therapy, the mortality rate is high. We present a patient with rhinocerebral mucormycosis involving the paranasal sinuses and cranial base who experienced long-term survival after multimodality treatment. Clinical characteristics of the disease are discussed, and the literature is reviewed.

CLINICAL PRESENTATION

A 24-year-old diabetic man presented with invasive rhinocerebral mucormycosis involving the paranasal sinuses, right middle fossa, and right cavernous sinus.

INTERVENTION

The patient underwent endovascular sacrifice of the involved carotid artery and radical resection of the cranial base, including exenteration of the cavernous sinus. Reconstruction with a local muscle flap was performed. He continued to receive intravenous and intrathecal administration of antibiotics.

CONCLUSION

Long-term survival with invasive rhinocerebral mucormycosis is rare, but possible, with aggressive multimodality treatment, including carotid sacrifice for en bloc resection of the pathology, when indicated.

A murine model of zygomycosis by Cunninghamella bertholletiae

Infections by Cunninghamella bertholletiae have been on the increase in recent years. However, little is known about this fungus and its infection. To clarify the pathogenicity of C. bertholletiae, we made a murine model, and to our knowledge, the first infectious model of this fungus. ICR mice pretreated with cortisone acetate and cyclophosphamide were inoculated intratracheally with 5 x 10(5) spores of C. bertholletiae. About half of the mice died by day 4 and 90% died by day 9. C. bertholletiae was cultured from the lungs, and the pathological analysis disclosed diffuse hyphal growth in the lungs, resulting in necrosis in the later stage. Angioinvasion with alveolar hemorrhage was extremely pronounced from the early stage, and this was the most characteristic feature of this infection. Treatment with amphotericin B showed only minimal improvement of survival, comparable to the poor result of this treatment in actual human cases. In fact, our model has many similarities to the actual human infection by C. bertholletiae, and will be useful for further investigations of this infection.

Rhinocerebral mucormycosis: a case of a rare, but deadly disease

Rhinocerebral mucormycosis is a rare fungal infection of the nasal cavity and sinuses that can spread to the orbits and cranium within days. Its presentation can be confused with those of sinusitis, viral infections, diabetic ketoacidosis, or carotid sinus thrombosis, and it is often missed at early presentation. Survival is directly linked to early detection and treatment. We present a case of rhinocerebral mucormycosis and discuss the literature on its early signs and symptoms, pathophysiology, and treatment options.

Endoscopic sinus surgery for rhinocerebral mucormycosis

Rhinocerebral mucormycosis is a fulminant, often fatal, disease. Aggressive surgical debridement has been considered an important part of treatment. Traditionally, an external or transantral approach has been the classic method. Recently, endoscopic sinus surgery (ESS) has been tried on several occasions to reach the goal of radical resection. Since 1991, ESS has been used to treat 9 rhinocerebral mucormycosis patients in our department. Among them, ESS was the only surgical procedure in six patients. The other three patients were treated by ESS combined with a transantral procedure. As a result, eight patients (88.9%) have survived the disease. One patient died 5 days after ESS because of an internal carotid artery occlusion. We conclude that ESS can be used to treat rhinocerebral mucormycosis alone or in combination with the traditional surgical procedures. It has the advantage of less operative morbidity and greater operative accuracy.

Treatment of rhinocerebral mucormycosis with intravenous interstitial, and cerebrospinal fluid administration of amphotericin B: case report

IMPORTANCE

Rhinocerebral mucormycosis is extremely difficult to treat. Approximately 70% of patients are poorly controlled diabetics, and many of the remainder are immunocompromised as a consequence of cytotoxic drugs, burn injuries, or end-stage renal disease. Despite standard treatment consisting of surgical debridement and the intravenous administration of amphotericin B, rhinocerebral mucormycosis is usually a fatal disease.

CLINICAL PRESENTATION

We describe the case of a 16-year-old male patient with juvenile onset diabetes mellitus who presented with fever, right-sided hemiparesis, and dysarthria. Axial view computed tomography revealed abscess formation in the left basal ganglia and frontal lobe, which was proven by stereotactic biopsy to contain Rhizopus oryzae.

INTERVENTION

Intravenous administration of amphotericin B (30-280 mg/dose) was begun on the day of admission. On hospital Day 20, after the occurrence of frank abscess formation, the lesion was aggressively debrided. Despite these therapies, there was neurological deterioration characterized by the development of hemiplegia and aphasia. Sequential computed tomographic scans enhanced with contrast medium demonstrated progressively enlarging lesions. Ommaya reservoirs were placed into the abscess cavity and the frontal horn of the contralateral lateral ventricle. The patient was then treated with intracavitary/interstitial injections of amphotericin B during the course of 80 days and three doses of intraventricular amphotericin B. Clinical and radiographic improvement was achieved after treatment. Two years after the initial diagnosis, magnetic resonance imaging of the brain showed no evidence of disease and an examination revealed a neurologically intact and fully functional patient.

CONCLUSION

We conclude that with an infection as morbid as rhinocerebral mucormycosis, it is advisable to use surgical debridement and all available routes for delivering amphotericin B to infected cerebral parenchyma, which include intravenous, intracavitary/interstitial, and cerebrospinal fluid perfusion pathways.

Long-term survival in rhinocerebral mucormycosis. Case report

Mucormycosis refers to a group of rapidly progressive infections caused by fungi belonging to the order Mucorales. Infection most often develops in individuals with immunological or metabolic compromise, although patients without underlying abnormalities have been affected. Specific clinical manifestations are associated with various predisposing factors. Rhinocerebral mucormycosis is the most common form and most frequently develops in individuals with poorly controlled diabetes mellitus. The extent of anatomical involvement and clinical course are unpredictable, depending on the intrinsic factors of the host. Over the past 20 years the prognosis for patients with rhinocerebral mucormycosis, once considered to be a uniformly fatal disease, has improved. Coordinated medical and surgical treatment, including rapid diagnosis, the advent of systemic antifungal agents, aggressive surgical debridement, and control of the underlying disease process, have been credited with its successful management. The range of survival rates recorded with the regimen of combined therapies is wide because the number of patients reported is limited and anatomical involvement is diverse. Survival with intracerebral abscess is rare. The authors describe the successful management of a patient who developed a bifrontal fungal abscess during treatment for rhinocerebral mucormycosis associated with ketoacidosis and diabetes mellitus. The patient remains without radiographic or clinical evidence of infection more than 2 years after treatment. The authors review the characteristic clinical, radiographic, and pathological features of previously reported infections and emphasize the importance of early detection and aggressive treatment in the management of this frequently fulminant and fatal disease.

Chronic rhinocerebral mucormycosis

Rhinocerebral mucormycosis is a well-described fulminant fungal infection that typically presents acutely in patients with diabetic ketoacidosis or immunosuppression. Chronic presentations of rhinocerebral mucormycosis have also been described. In the chronic infection, the disease course is indolent and slowly progressive, often occurring over weeks to months. The authors report 2 cases of chronic rhinocerebral mucormycosis (CRM) treated at their institution and review 16 other cases reported in the English-language literature. In these cases, the median time from symptom onset to diagnosis was 7 months. The most common presenting features of CRM are ophthalmologic and include ptosis, proptosis, visual loss, and ophthalmoplegia. CRM occurs predominantly in patients with diabetes and ketoacidosis. The incidence of internal carotid artery and cavernous sinus thrombosis is higher in CRM patients than in those with the acute disease, although the overall survival rate for CRM patients is 83%. CRM is clinically distinct from chronic Entomophthorales infection.

Mucormycosis (zygomycosis): is there news for the clinician?

New data on mucormycosis (zygomycosis), relevant to the clinician, are analysed. Several clinical associations of this fungal infection have recently emerged: the association with therapy with the metal chelator desferrioxamine (mainly in dialysis patients), the rarity of mucormycosis in AIDS patients and its sporadic occurrence after bone marrow transplantation. New imaging techniques should be used serially in the case of rhinocerebral mucormycosis in order to evaluate the extent of the lesions and to guide potential surgery. Surgical debridement significantly improves the prognosis of rhinocerebral mucormycosis. Finally, results of the use of liposomal amphotericin B in a few patients with rhinocerebral mucormycosis are reviewed.

Deferoxamine augments growth and pathogenicity of Rhizopus, while hydroxypyridinone chelators have no effect

Deferoxamine (DFO), when used in dialysis patients, is a well recognized risk factor for the development of mucormycosis caused by Rhizopus. This study compares, both in vivo and in vitro, the effects produced on Rhizopus by DFO and by two chelators of the hydroxypyridinone class, L1 and CP94. Experimental systemic mucormycosis was induced in the guinea pig by an i.v. injection of two different strains of Rhizopus: R. microsporus and R. arrhizus. Concomitant i.p. administration of DFO for four days shortened animal survival (P < 0.05), whereas concomitant administration of either L1 or CP94 did not. In vitro radioiron uptake by R. microsporus was 100-fold higher from the 55ferric complex of DFO than of L1 or CP94. In vitro fungal growth was stimulated sevenfold by the ferric complex of DFO (P < 0.0001) but not significantly by the ferric complex of either L1 or CP94. These results indicate that the ferric complex of DFO but not that of L1 or CP94 specifically stimulates both the iron uptake and the growth of Rhizopus. They suggest that the risk of developing mucormycosis should be minimal with L1 or CP94, as opposed to DFO.