Part 1: Mucormycosis: prevalence, risk factors, clinical features, and diagnosis

ABSTRACT

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; or (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: invasivefungal 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.

KEYWORDS:

• Invasive fungal infections
• mold
• mucormycosis
• Mucorales
• Zyzomyces
• Zygomycosis
• Rhizopus
• diagnosis

Article highlights

• Mucormycosis (MCR) is an infection caused by filamentous molds within the Class Zygomycetes and Orders Mucorales and Entomophthorales

• Mucorales occupy environmental niches including soil, dust, decaying vegetable matter, and food

• Infections due to Mucorales can result from inhalation of spores into the respiratory tract, ingestion of contaminated foods or inoculation of disrupted skin or wounds

• The incidence/prevalence of MCR is difficult to estimate since MCR is not reportable. In most developed countries, incidence rates range from 1 to 4 cases per 100,000

• In developed or high-income countries, nearly all cases of MCR occur in immunocompromised individuals or those with specific risk factors

• In developing or low-income countries, most cases of MCR occur in patients with poorly controlled diabetes mellitus

• Based on anatomic localization, MCR can be classified as one of six forms: rhino-orbital-cerebral MCR, pulmonary, skin/soft tissue infection, gastrointestinal or renal, disseminated, or uncommon sites

• The diagnosis of MCR relies upon histopathology and culture

• Conditions/risk factors associated with MCR include poorly controlled diabetes mellitus

• Mortality rates of MCR depend on site(s) of disease and patient comorbidities.

Declaration of interest

GG Zhanel has received research funding from Avir, Iterum, Merck & Co, Paladin labs, Pfizer Inc, Sandoz, Venatorx, Verity, and Zambon. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

All authors have substantially contributed to the conception, design of the review article, interpreting the relevant literature and writing the review article.

Additional information

Funding

The paper was not funded.