CLINICAL CHALLENGES OF EMERGING FUNGAL INFECTIONS IN THE CONTEXT OF CLIMATE CHANGE: A CASE SERIES

Global warming and climate change are increasingly influencing the emergence of fungal pathogens, posing significant challenges in medical mycology. It may create favorable conditions for fungi to thrive in new geographic areas, leading to more frequent infections in susceptible populations, such as contact lens wearers and those using immunosuppressive therapies. This report describes three distinct cases, highlighting the growing threat of fungal infections influenced by climate change. It also raises the question of which is the highlighting feature: the impact of global warming on fungal ecosystems or the increasing advances in diagnosing and identifying fungal infections. Case 1: Schizophyllum commune, a basidiomycetous fungus commonly found in decaying plant matter, is an opportunistic pathogen primarily affecting the respiratory system. The rise in temperature and environmental disruption have increased human exposure to airborne fungal spores, leading to a growing number of infections worldwide. This case describes a 49-year-old immunocompetent woman who developed chronic non-invasive fungal rhinosinusitis caused by S. commune. The patient presented with a 3-month history of headaches, nasal obstruction, and hyposmia. Diagnostic confirmation was achieved through computed tomography (CT), DNA sequencing of ribosomal DNA regions, and MALDI-TOF mass spectrometry. The patient underwent endoscopic sinus surgery to remove the fungal mass, resulting in full recovery without recurrence. Case 2: The second case describes a 6-year-old neutropenic child with acute myeloid leukemia who developed acute appendicitis due to Aspergillus carneus, a rare species of Aspergillus. Despite prophylactic antifungal treatment, the patient required an appendectomy, and histopathological examination revealed invasive fungal elements. Molecular identification confirmed A. carneus, and antifungal therapy with voriconazole led to a successful recovery. This case underscores the risk of invasive fungal infections in immunocompromised patients, particularly with rare fungal species of which antifungal susceptibilities are unknown. Case 3: This unpublished case report describes a 52-year-old patient with fungal keratitis caused by Pyrenochaeta unguis-hominis, a fungus typically found in soil and plant debris and has been associated with nail infections. Corneal scraping was sent to the Microbiology lab for culturing which resulted in a growth on Sabouraud Dextrose Agar on day 10 with no indication to the genus involved. Molecular identification was performed using TEF1α and ITS barcodes. The slow-growing nature of the fungus in addition to the challenging identification has led to late initiation of voriconazole, prolonging the patient’s recovery. The emerging role of Pyrenochaeta unguis-hominis as a human pathogen, especially in the context of keratitis, suggests that environmental changes, such as shifts in fungal ecosystems, may increase human exposure to previously rare fungal species. References 1. Cavanna C, Pagella F, Esposto MC, Tamarozzi F, Clemente L, Marone P, Matti E, Lallitto F. Human infections due to Schizophyllumcommune: Case report and review of the literature. J Mycol Med. 2019; 29 (4): 365-371. doi: 10.1016/j.mycmed.2019.100897. Epub 2019 Sep 12. PMID: 31543381. 2. Decembrino N, Zecca M, Tortorano AM, Mangione F, Lallitto F, Introzzi F, Bergami E, Marone P, Tamarozzi F, Cavanna C. Acute isolated appendicitis due to Aspergillus carneus in a neutropenic child with acute myeloid leukemia. New Microbiol. 2016; 39 (1): 65-69. PMID: 26922988