Epidemiology of COVID-19-Associated Mucormycosis

Corona-Associated Mucormycosis: Case Series Reports and Review of the Literature

During the COVID-19 pandemic, a significant increase in cases of mucormycosis was observed in COVID-19 patients, especially in India, but not exclusively. The presented cases highlight the heterogeneous nature of mucormycosis, emphasizing the importance of recognizing predisposing factors, such as immunosuppression, due to comorbidities or medication. Diagnosing mucormycosis poses a challenge due to nonspecific clinical manifestations, requiring a multidisciplinary approach for accurate diagnosis. Treatment involves a multi-pronged approach centered around the early initiation of antifungal therapy alongside surgical intervention and the management of underlying conditions, with an emphasis on controlling immunosuppression. Understanding the relationship between COVID-19 and predisposing factors for mucormycosis is fundamental for developing prevention and treatment strategies.

Molecular mechanisms that govern infection and antifungal resistance in Mucorales

SUMMARYThe World Health Organization has established a fungal priority pathogens list that includes species critical or highly important to human health. Among them is the order Mucorales, a fungal group comprising at least 39 species responsible for the life-threatening infection known as mucormycosis. Despite the continuous rise in cases and the poor prognosis due to innate resistance to most antifungal drugs used in the clinic, Mucorales has received limited attention, partly because of the difficulties in performing genetic manipulations. The COVID-19 pandemic has further escalated cases, with some patients experiencing the COVID-19-associated mucormycosis, highlighting the urgent need to increase knowledge about these fungi. This review addresses significant challenges in treating the disease, including delayed and poor diagnosis, the lack of accurate global incidence estimation, and the limited treatment options. Furthermore, it focuses on the most recent discoveries regarding the mechanisms and genes involved in the development of the disease, antifungal resistance, and the host defense response. Substantial advancements have been made in identifying key fungal genes responsible for invasion and tissue damage, host receptors exploited by the fungus to invade tissues, and mechanisms of antifungal resistance. This knowledge is expected to pave the way for the development of new antifungals to combat mucormycosis. In addition, we anticipate significant progress in characterizing Mucorales biology, particularly the mechanisms involved in pathogenesis and antifungal resistance, with the possibilities offered by CRISPR-Cas9 technology for genetic manipulation of the previously intractable Mucorales species.

[Fatal case of rhinocerebral mucormycosis on the background of type II diabetes mellitus]

Mucormycosis is a disease caused by fungi of the Mucorales family, widespread in the environment, with pronounced angiotropism and the ability to angioinvasion, leading to thrombosis with surrounding necrosis. The main triggers for the development of mucormycosis are: immunodeficiency states, use of glucocorticosteroid drugs, decompensation of diabetes mellitus, concomitant diseases, age > 65 years. We present a clinical case of rhinocerebral mucormycosis in a 79-year-old patient against the background of uncontrolled type 2 diabetes mellitus with ketoacidosis, a condition after previous glucocorticosteroid therapy for COVID-19 (according to the severity of the disease). After suffering a new coronavirus infection caused by the SARS-CoV-2 virus, she was admitted to the hospital with complaints characteristic of mucormycosis. On the 5th day of hospital stay, the patient's condition worsened significantly, despite the correction of the therapy, and on the 12th day the patient died. According to the results of the autopsy, it was established that the rhinocerebral mucormycosis was complicated by thrombosis of the anterior and posterior left cerebral arteries with subsequent infarctions in the frontal lobe and parieto-occipital region of the brain left hemisphere, cerebral edema, which was the immediate cause of death.

Combating Black Fungus: Using Allicin as a Potent Antifungal Agent against Mucorales

Invasive fungal (IF) diseases are a leading global cause of mortality, particularly among immunocompromised individuals. The SARS-CoV-2 pandemic further exacerbated this scenario, intensifying comorbid IF infections such as mucormycoses of the nasopharynx. In the work reported here, it is shown that zygomycetes, significant contributors to mycoses, are sensitive to the natural product allicin. Inhibition of Mucorales fungi by allicin in solution and by allicin vapor was demonstrated. Mathematical modeling showed that the efficacy of allicin vapor is comparable to direct contact with the commercially available antifungal agent amphotericin B (ampB). Furthermore, the study revealed a synergistic interaction between allicin and the non-volatile ampB. The toxicity of allicin solution to human cell lines was evaluated and it was found that the half maximal effective concentration (EC50) of allicin was 25-72 times higher in the cell lines as compared to the fungal spores. Fungal allicin sensitivity depends on the spore concentration, as demonstrated in a drop test. This study shows the potential of allicin, a sulfur-containing defense compound from garlic, to combat zygomycete fungi. The findings underscore allicin's promise for applications in infections of the nasopharynx via inhalation, suggesting a novel therapeutic avenue against challenging fungal infections.