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Published on: October 28, 2021

Fusarium spp. as agents of onychomycosis in immunocompetent hosts

Eliana Guilhermetti1, Gisele Takahachi, Cristiane Suemi Shinobu

  • 1Laboratory of Medical Mycology, Maringá State University, Maringá, Paraná, Brazil.

International Journal of Dermatology
|July 27, 2007
PubMed
Abstract

Insights

Fusarium fungi cause onychomycosis (nail infections) in immunocompetent individuals. Clinical signs and laboratory tests can help distinguish infection from contamination, with amphotericin B showing low resistance.

Area of Science:

  • Medical Mycology
  • Dermatology
  • Infectious Diseases

Background:

  • Fusarium species are filamentous fungi often implicated in opportunistic infections.
  • Their role in cutaneous lesions, particularly in immunocompetent patients, remains debated, often being misidentified as contaminants.

Purpose of the Study:

  • To determine the prevalence of onychomycosis caused by Fusarium spp. in immunocompetent patients in Maringá, Paraná, Brazil.
  • To establish clinical and laboratory criteria for diagnosing Fusarium onychomycosis.
  • To assess the susceptibility of Fusarium isolates to key systemic antifungal drugs used in Brazil.

Main Methods:

  • Fungal isolation and identification using classical mycological methods.
  • Antifungal susceptibility testing performed according to National Committee for Clinical Laboratory Standards (NCCLS) M38-A protocol.

Main Results:

  • Fusarium species were identified in 7.5% (27/360) of confirmed onychomycosis cases, with Fusarium oxysporum being the most frequent species.
  • Predictive indicators for Fusarium onychomycosis included paronychia, pain, suggestive microscopy, and high fungal load.
  • High minimum inhibitory concentrations (MICs) were observed for itraconazole, ketoconazole, and terbinafine, while amphotericin B showed low MICs.

Conclusions:

  • Fusarium species should be considered a significant cause of onychomycosis, even in immunocompetent individuals.
  • Development of specific criteria is crucial to differentiate true Fusarium infections from mere contamination in clinical samples.
  • Further attention to Fusarium species identification and interpretation in superficial mycoses is warranted.

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