RRC ID 74522
Author Kano R, Noguchi H, Hiruma M.
Title A deletion mutation in the amino acid sequence of squalene epoxidase in terbinafine-resistant Trichophytonrubrum.
Journal J Infect Chemother
Abstract INTRODUCTION:Trichophyton rubrum is an anthropophilic dermatophyte that is most frequently isolated from onychomycosis (tinea unguium) worldwide. T. rubrum strains showing resistance to the anti-fungal drug terbinafine (TRF) have also been isolated from human patients worldwide.
METHODS:In this study, we isolated a TRF-resistant strain (N99-2) of T. rubrum from a patient with recurrent tinea unguium. In vitro susceptibility of the clinical isolate to TRF, itraconazole (ITZ), ravuconazole (RVZ), and luliconazole (LCZ) was investigated using the Clinical & Laboratory Standards Institute M38-A2 test. To identify mutations, we compared the gene sequence of N99-2 to that of a TRF-susceptible strain of T. rubrum. Results; In N99-2, the minimum inhibitory concentrations were 32 mg/L for TRF, <0.03 mg/L for ITZ, <0.03 mg/L for RVZ, and <0.03 mg/L for LCZ. The squalene epoxidase (SQLE) gene sequence in N99-2 was determined to be 1467 bp in length, and it encoded a protein of 488 amino acids, beginning with a putative initiating methionine (ATG). The following mutations were identified from the SQLE of N99-2: L393F and Y394del.
CONCLUSIONS:This is the first report of the detection of a deletion mutation in SQLE in a TRF-resistant strain. The protein of SQLE is the target of TRF, and it is essential for cell membrane synthesis in dermatophytes. However, dermatophyte cells were found to undergo gene mutations to escape the effects of antifungal agents.
Volume 28(6)
Pages 741-744
Published 2022-6-1
DOI 10.1016/j.jiac.2022.02.010
PII S1341-321X(22)00051-4
PMID 35219578
MeSH Amino Acid Sequence Antifungal Agents / pharmacology Antifungal Agents / therapeutic use Drug Resistance, Fungal / genetics Humans Itraconazole / pharmacology Microbial Sensitivity Tests Onychomycosis* / drug therapy Onychomycosis* / genetics Sequence Deletion Squalene Monooxygenase* / genetics Terbinafine / pharmacology Trichophyton / genetics
IF 1.722
Resource
Pathogenic eukaryotic microorganisms Trichophyton rubrum IFM 66683