Pulmonary Mucormycosis: A Case Report of a Rare Infection with Potential Diagnostic Problems

Value of Imprint Cytology for the Rapid Diagnosis of Mucormycosis in the COVID-19 Pandemic Setting - A Pilot Study

Background

The second wave of the coronavirus disease 2019 (COVID-19) pandemic recorded a surge in rhino-orbital-cerebral mucormycosis (ROCM) infection in COVID-19-positive patients with diabetes and on concomitant steroid therapy. The rapidly progressive and devastating nature of the disease necessitated prompt diagnosis and early intervention to improve patient outcomes. Histopathology and fungal culture remain essential tools; however, these investigations have long and variable turn-around times (TATs) and may delay the initiation of treatment. Frozen section is not widely available and should be avoided in COVID-19-positive cases due to the risk of aerosol production and droplet exposure. In cases with high clinicoradiologic suspicion for mucormycosis, imprint cytologic evaluation provides a rapid diagnosis. Familiarity with fungal cytomorphology, awareness of morphologic pitfalls, and implementation of a standardized reporting format aid in diagnostic accuracy.

Method

Eighteen COVID-19-positive patients, who were admitted to our hospital with clinical suspicion of mucormycosis during June and July 2021, were included in the study. We used nasal or oral imprint cytology for the initial, rapid detection of Mucor. Cytology findings were correlated with histopathology and fungal culture results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

Results

The sensitivity, specificity, PPV, and NPV were 100%, 100%, 100% and 100%, respectively.

Conclusion

This study showed that imprint cytology can be a rapid, cost-effective, first-line diagnostic modality in Mucor diagnosis.

Antifungal Effect of Nanoparticles against COVID-19 Linked Black Fungus: A Perspective on Biomedical Applications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible and pathogenic coronavirus that has caused a 'coronavirus disease 2019' (COVID-19) pandemic in multiple waves, which threatens human health and public safety. During this pandemic, some patients with COVID-19 acquired secondary infections, such as mucormycosis, also known as black fungus disease. Mucormycosis is a serious, acute, and deadly fungal infection caused by Mucorales-related fungal species, and it spreads rapidly. Hence, prompt diagnosis and treatment are necessary to avoid high mortality and morbidity rates. Major risk factors for this disease include uncontrolled diabetes mellitus and immunosuppression that can also facilitate increases in mucormycosis infections. The extensive use of steroids to prevent the worsening of COVID-19 can lead to black fungus infection. Generally, antifungal agents dedicated to medical applications must be biocompatible, non-toxic, easily soluble, efficient, and hypoallergenic. They should also provide long-term protection against fungal growth. COVID-19-related black fungus infection causes a severe increase in fatalities. Therefore, there is a strong need for the development of novel and efficient antimicrobial agents. Recently, nanoparticle-containing products available in the market have been used as antimicrobial agents to prevent bacterial growth, but little is known about their efficacy with respect to preventing fungal growth, especially black fungus. The present review focuses on the effect of various types of metal nanoparticles, specifically those containing silver, zinc oxide, gold, copper, titanium, magnetic, iron, and carbon, on the growth of various types of fungi. We particularly focused on how these nanoparticles can impact the growth of black fungus. We also discussed black fungus co-infection in the context of the global COVID-19 outbreak, and management and guidelines to help control COVID-19-associated black fungus infection. Finally, this review aimed to elucidate the relationship between COVID-19 and mucormycosis.

The TLR-NF-kB axis contributes to the monocytic inflammatory response against a virulent strain of Lichtheimia corymbifera, a causative agent of invasive mucormycosis

Invasive mucormycosis (IM) is a life-threatening infection caused by the fungal order Mucorales, its diagnosis is often delayed, and mortality rates range from 40-80% due to its rapid progression. Individuals suffering from hematological malignancies, diabetes mellitus, organ transplantations, and most recently COVID-19 are particularly susceptible to infection by Mucorales. Given the increase in the occurrence of these diseases, mucormycosis has emerged as one of the most common fungal infections in the last years. However, little is known about the host immune response to Mucorales. Therefore, we characterized the interaction among L. corymbifera—one of the most common causative agents of IM—and human monocytes, which are specialized phagocytes that play an instrumental role in the modulation of the inflammatory response against several pathogenic fungi. This study covered four relevant aspects of the host-pathogen interaction: i) The recognition of L. corymbifera by human monocytes. ii) The intracellular fate of L. corymbifera. iii) The inflammatory response by human monocytes against the most common causative agents of mucormycosis. iv) The main activated Pattern-Recognition Receptors (PRRs) inflammatory signaling cascades in response to L. corymbifera. Here, we demonstrate that L. corymbifera exhibits resistance to intracellular killing over 24 hours, does not germinate, and inflicts minimal damage to the host cell. Nonetheless, viable fungal spores of L. corymbifera induced early production of the pro-inflammatory cytokine IL-1β, and late release of TNF-α and IL-6 by human monocytes. Moreover, we revealed that IL-1β production predominantly depends on Toll-like receptors (TLRs) priming, especially via TLR4, while TNF-α is secreted via C-type lectin receptors (CTLs), and IL-6 is produced by synergistic activation of TLRs and CTLs. All these signaling pathways lead to the activation of NF-kB, a transcription factor that not only regulates the inflammatory response but also the apoptotic fate of monocytes during infection with L. corymbifera. Collectively, our findings provide new insights into the host-pathogen interactions, which may serve for future therapies to enhance the host inflammatory response to L. corymbifera.

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.

Pulmonary Aspergillus and Mucor Co-Infection: A report of two cases

Co-infections or consecutive infections of mucormycosis and aspergillosis are very rare. Additionally, distinguishing between these two infections is also difficult as both these conditions have similar clinical features. We report two similar cases from Tamilnadu, who presented to a tertiary care centre in Puducherry, India in 2017 (first case) and 2019 (second case). The first case was a 70-year-old, non-diabetic male patient who presented with haemoptysis with a prior history of pulmonary tuberculosis. Computed tomography bronchial angiography revealed an air-crescent sign and the histopathological examination showed a fungal ball (aspergillus and mucor) in the right upper lobe and foci of fungal infection in the middle lobe. The second case was a 65-year-old diabetic male patient who presented with blackish expectoration and haemoptysis. A high-resolution computed tomography scan showed a reverse-halo sign in the right upper lobe. The results of the bronchoscopy-guided biopsy were consistent with a diagnosis of mixed mucormycosis and aspergillosis with angioinvasion. Both patients responded to amphotericin B with surgical excision of the affected lobe in the first case. A high degree of clinical suspicion, early surgical intervention and antifungal therapy are essential in the treatment of this rare co-infection.

Predisposing factors of important invasive fungal coinfections in COVID-19 patients: a review article

Severe acute respiratory syndrome coronavirus-2 has caused a devastating pandemic lasting for more than a year. To date, 47 million individuals have been infected and 1.2 million individuals have died worldwide. Some of the most important coinfections in patients with coronavirus disease 2019 (COVID-19) are opportunistic invasive fungal infections (OIFIs), which are sometimes not rapidly diagnosed and are often diagnosed after death. Aspergillosis and candidiasis are the most prevalent OIFIs in patients with COVID-19. Mycormycosis, cryptococcosis, and other fungal diseases have also been documented more rarely. This review aimed to summarize factors affecting COVID-19 transmission, prevalence, morbidity, and mortality in Iran as well as to review common OIFIs in patients with COVID-19. Immunological factors, underlying diseases, and social, cultural, and environmental factors can affect COVID-19 transmission. There is a need to improve diagnostic and therapeutic criteria for OIFIs and to optimize management procedures so that patients with OIFIs can receive treatment as rapidly as possible. Screening of patients with confirmed COVID-19 for OIFIs at the treating physician’s discretion could enable early OIFI diagnosis, treatment, and mortality reduction.

Lactoferrin, a potential iron-chelator as an adjunct treatment for mucormycosis - A comprehensive review

Mucormycosis is a deadly infection which is caused by fungi of the order Mucorales including species belonging to the genus Rhizopus, Mucor, Mycocladus, Rhizomucor, Cunninghamella, and Apophysomyces. Despite antifungal therapy and surgical procedures, the mortality rate of this disease is about 90-100% which is exceptionally high. The hypersensitivity of patients with raised available serum iron indicates that the Mucorales are able to use host iron as a critical factor of virulence. This is because iron happens to be a crucial element playing its role in the growth of cells and development. In this review, we have described Lactoferrin (Lf) as a potential iron-chelator. Lf is a naturally occurring glycoprotein which is expressed in most of the biological fluids. Moreover, Lf possesses exclusive anti-inflammatory effects along with several anti-fungal effects that could prove to be helpful to the pathological physiology of inexorable mucormycosis cases. This literature summarises the biological insights into the Lf being considered as a potential fungistatic agent and an immune regulator. The review also proposes that unique potential of Lf as an iron-chelator can be exploited as the adjunct treatment for mucormycosis infection.

A rare entity to major outbreak: a case report on mucormycosis

Mucormycosis is relatively uncommon, fulminant, progressive, life threatening fungal disease which is most often seen in debilitating patients with immunocompromised condition. Mucormycosis cases are seen in patients with the use of systemic steroids in the treatment of severely affected COVID-19 cases and also in the patients with uncontrolled diabetes which causes immunosuppression are being reported with mucormycosis. The main symptoms of this disease include pain on the temporal and the orbital region of the affected side which could be throbbing or lancinating type, mobility of the teeth, jaw pain and often swelling is present which could be extraoral and intraoral both or sometimes only intraorally. The diagnostic approach in such cases is done with the help of clinical diagnosis, histopathology and with advanced imaging like cone beam computed tomography, magnetic resonance imaging and computed tomography. We here used cone beam computed tomography imaging that revealed haziness in the sinuses and breach in cortical bone of the affected area which confirmed the diagnosis of mucormycosis. Early treatment planning like administration of antifungal drugs and surgical debridement will be life saving in such a deadly disease.

Coronavirus Disease-Associated Mucormycosis from a Tertiary Care Hospital in India: A Case Series

BACKGROUND

 Coronavirus disease (COVID-19) remains a health concern with new challenges emerging as the pandemic progresses. The recent rise of opportunistic infections especially mucormycosis in COVID-19 patients is further complicating their outcomes. Mucormycosis is well known to infect patients with diabetes mellitus, malignancy, chemotherapy, and other immunocompromised conditions. The treatment of COVID-19 largely remains systemic steroids and other immunomodulators that add to the risk of invasive fungal infection.

METHODOLOGY

Here, we present a retrospective case series of 13 patients with individual clinical characteristics along with the demography and treatment details. The data were collected retrospectively in a single center that caters to a large population of COVID-19 patients with varying severity.

RESULTS

Thirteen patients were presented with COVID-19 associated mucormycosis (CAM). The median age was higher in non-survivors (49.5 years), with a higher odds of death (23.8) in those with severe COVID, having overall mortality of 64.3%. Moreover, diabetes mellitus was present in 61.5% of patients with a mortality of 75%. About 11 (84.6%) patients had received prior steroids for COVID-19. The incidence of hyperglycemia at admission was equal among both survivors and non-survivors.

CONCLUSION

The prevalence of mucormycosis seems to be increasing among COVID-19 patients which may be associated with increased use of steroids, the possible immunocompromised state imposed by SARS-CoV-2, or co-existing conditions such as diabetes mellitus. The mortality of CAM is remarkably high and apart from preventive practices and rational use of immunomodulators, a high index of suspicion with early diagnosis would be key to survival.

Pulmonary Mucormycosis: An Interesting Case of Rhizopus Mucormycosis

We report a case of a 57-year-old Vietnamese gentleman who presented with chest pain and shortness of breath for four weeks. The patient had a history of diabetes mellitus and kidney transplant in the past year and was currently on immunosuppressive agents. The patient's condition worsened despite broad-spectrum antibiotics, so amphotericin was added. Further evaluation with bronchoscopy and transbronchial biopsy was suggestive of Rhizopus mucormycosis. Despite antifungal therapy, his condition worsened, resulting in multi-organ failure and eventual mortality.

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.