Genetic diversity and antifungal susceptibility of Fusarium isolates in onychomycosis

Abstract

Fusarium species have emerged as an important human pathogen in skin disease, onychomycosis, keratitis and invasive disease. Onychomycosis caused by Fusarium spp. The infection has been increasingly described in the immunocompetent and immunosuppressed hosts. Considering onychomycosis is a difficult to treat infection, and little is known about the genetic variability and susceptibility pattern of Fusarium spp., further studies are necessary to understand the pathogenesis and better to define the appropriate antifungal treatment for this infection. Accordingly, the objective of this study was to describe the in vitro susceptibility to different antifungal agents and the genetic diversity of 35 Fusarium isolated from patients with onychomycosis. Fusarium spp. were isolated predominantly from female Caucasians, and the most frequent anatomical location was the nail of the hallux. Results revealed that 25 (71.4%) of isolates belonged to the Fusarium solani species complex, followed by 10 (28.5%) isolates from the Fusarium oxysporum species complex. Noteworthy, the authors report the first case of Neocosmospora rubicola isolated from a patient with onychomycosis. Amphotericin B was the most effective antifungal agent against the majority of isolates (60%, MIC ≤4 μg/mL), followed by voriconazole (34.2%, MIC ≤4 μg/mL). In general, Fusarium species presented MIC values >64 μg/mL for fluconazole, itraconazole and terbinafine. Accurate pathogen identification, characterisation and susceptibility testing provide a better understanding of pathogenesis of Fusarium in onychomycosis.

Molecular identification and antifungal susceptibility of clinical fungal isolates from onychomycosis (uncommon and emerging species)

“…This finding is not compatible with the previous epidemiological evaluations conducted in Iran and other countries worldwide in which dermatophyte family and Candida species were, respectively, introduced as the most common agents of onychomycosis . However, our finding is similar to others where Aspergillus and Fusarium species were the predominant agents of fungal nail infection . Aspergillus species are growingly reported as the principal agents of non‐dermatophyte onychomycosis worldwide with a prevalence of as high as 59.8% in Malaysia, 42.7% in Tunisia, 50% in Brazil, 69.3% in Iran and up to 83% in Korea .…”

“…Similar results were observed in a study performed by Guevara‐Suarez et al in Colombia, who identified the members of F. solani species complex, including F. falciforme , F. keratoplasticum , F. lichenicola and F. petroliphilum , as well as species of Fusarium oxysporum species complex. In the current study, for the first time, F. proliferatum was identified as the predominant species; however, F. keratoplasticum was the second common isolate similar to the results obtained by Rosa et al . Of all antifungal agents, only the new imidazoles, namely luliconazole and lanoconazole, as well as new triazoles, including efinaconazole, posaconazole and voriconazole, respectively, showed remarkable and moderate activities against Fusarium isolates.…”

“…Few studies reported data regarding the predominance of filamentous fungi and yeast over dermatophytes in onychomycosis . According to the considerable body of literature, the most prevalent isolated pathogens detected in nail fungal infections are dermatophytes, followed by yeast and moulds .…”

Allylic Selenocyanates as New Agents to Combat Fusarium Species Involved with Human Infections

“…They are known to be opportunistic microorganisms which may cause local or systemic infections and present the most diverse antifungal resistance panel of drugs that include voriconazole, posaconazole, and amphotericin B. Clinical manifestation depends on the immune status of the host being neutropenia the major risk factor for acquiring infections . Fusariosis represents the second most prevalent cause of systemic filamentous fungal infection after aspergillosis .…”

“…In Brazil, invasive Fusarium infections are identified in 40–60% of blood cultures being the fungus identified in 60–80% of the patients presenting cutaneous lesions ,,. The mortality of disseminated Fusarium infections to immunocompromised patients ranges from 50 to 70% being related to the therapy ,,,,…”