Successful treatment of pulmonary mucormycosis in two pediatric hematopoietic stem cell transplant patients

Part 1: Mucormycosis: Prevalence, Risk Factors, Clinical Features and Diagnosis

INTRODUCTION

Mucormycosis (MCR) is caused by filamentous molds within the Class Zygomycetes and Order Mucorales. Infections can result from inhalation of spores into the nares, oropharynx or lungs, ingestion of contaminated food or water, or inoculation into disrupted skin or wounds. In developed countries, MCR occurs primarily in severely immunocompromised hosts. In contrast, in developing/low income countries, most cases of MCR occur in persons with poorly controlled diabetes mellitus and some cases in immunocompetent subjects following trauma. Mucormycosis exhibits a propensity to invade blood vessels, leading to thrombosis and infarction of tissue. Mortality rates associated with invasive MCR are high and can exceed 90% with disseminated disease. Mucormycosis can be classified as one of six forms: (1) rhino-orbital-cerebral mucormycosis (ROCM); (2) pulmonary; (3) cutaneous; (4) gastrointestinal or renal (5); disseminated; (6) uncommon (focal) sites.

AREAS COVERED

The authors discuss the prevalence, risk factors and clinical features of mucormycosis.A literature search of mucormycosis was performed via PubMed (up to November 2022), using the key words: invasive fungal infections; mold; mucormycosis; Mucorales; Zyzomyces; Zygomycosis; Rhizopus, diagnosis.

EXPERT OPINION

Mucormycosis occurs primarily in severely immunocompromised hosts. Mucormycosis can progress rapidly, and delay in initiating treatment by even a few days worsens outcomes.

Mucormycosis: risk factors, diagnosis, treatments, and challenges during COVID-19 pandemic

Mucormycosis is a deadly opportunistic disease caused by a group of fungus named mucormycetes. Fungal spores are normally present in the environment and the immune system of the body prevents them from causing disease in a healthy immunocompetent individual. But when the defense mechanism of the body is compromised such as in the patients of diabetes mellites, neustropenia, organ transplantation recipients, and other immune-compromised states, these fungal spores invade our defense mechanism easily causing a severe systemic infection with approximately 45-80% of case fatality. In the present scenario, during the COVID-19 pandemic, patients are on immunosuppressive drugs, glucocorticoids, thus are at high risk of mucormycosis. Patients with diabetes mellitus are further getting a high chance of infection. Usually, the spores gain entry through our respiratory tract affecting the lungs and paranasal sinuses. Besides, they can also enter through damage into the skin or through the gastrointestinal route. This review article presents the current statistics, the causes of this infection in the human body, and its diagnosis with available recent therapies through recent databases collected from several clinics and agencies. The diagnosis and identification of the infection were made possible through various latest medical techniques such as computed tomography scans, direct microscopic observations, MALDI-TOF mass spectrometry, serology, molecular assay, and histopathology. Mucormycosis is so uncommon, no randomized controlled treatment studies have been conducted. The newer triazoles, posaconazole (POSA) and isavuconazole (ISAV) (the active component of the prodrug isavuconazonium sulfate) may be beneficial in patients who are refractory to or intolerant of Liposomal Amphotericin B. but due to lack of early diagnosis and aggressive surgical debridement or excision, the mortality rate remains high. In the course of COVID-19 treatments, there must be more vigilance and alertness are required from clinicians to evaluate these invasive fungal infections.