# Epidemiology of mucormycosis in COVID-19 patients in northwest Iran: Rhizopus arrhizus as the predominant species

## TL;DR

This study examines mucormycosis in COVID-19 patients in Iran, finding Rhizopus arrhizus as the main cause and highlighting risks from corticosteroid use.

## Contribution

The study identifies Rhizopus arrhizus as the predominant mucormycosis species in northwest Iran and links corticosteroid therapy to increased risk.

## Key findings

- Mucormycosis was confirmed in 63 COVID-19 patients, with an average age of 56.65 years.
- Rhizopus arrhizus was the main causative agent identified in 33% of positive cultures.
- Most cases occurred in the sinuses, and corticosteroid use was common among affected patients.

## Abstract

The current study aimed to assess the demographic features, clinical characteristics, species diversity, and contributing factors among patients with severe acute respiratory syndrome coronavirus-2 pneumonia-associated mucormycosis in northwestern Iran.

This cross-sectional descriptive study was performed on patients who tested positive for COVID-19 via reverse-transcriptase-polymerase chain reaction and were suspected of having invasive fungal infection. Mucormycosis was confirmed by histopathology of biopsy samples and species identification was performed using morphological and internal transcribed spacer-rDNA sequencing methods.

Mucormycosis was observed in 63 COVID-19 patients. Mean age of patients was 56.65±14.49 years (range of 22-85 years) and 63.5% of the involved patients were male.
The most common involvement site of patients with mucormycosis was the sinus (63.5%). Among all participants, 84% of patients (n=53) had received intravenous dexamethasone, and 25.4% of them
had diabetes mellitus. All patients with proven invasive mucormycosis received intravenous amphotericin B. In total, 21 (33%) positive cultures
were identified and Rhizopus arrhizus was the main causative agent.

Awareness among physicians should be raised that corticosteroid therapy not only causes dysfunction of the immune system but may also lead to the development of this neglected mycosis through corticosteroid-induced diabetes in vulnerable patients.