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. 2020 Mar 13:13:845-850.
doi: 10.2147/IDR.S246025. eCollection 2020.

Emergence of Terbinafine Resistant Trichophyton mentagrophytes in Iran, Harboring Mutations in the Squalene Epoxidase (SQLE) Gene

Simin Taghipour  1 , Forough Shamsizadeh  2 , Ivan M Pchelin  3 , Ali Rezaei-Matehhkolaei  4 , Ali Zarei Mahmoudabadi  4 , Reza Valadan  5 , Saham Ansari  6 , Farzad Katiraee  7 , Keyvan Pakshir  8 , Kamiar Zomorodian  8 , Mahdi Abastabar  9
Affiliations

Emergence of Terbinafine Resistant Trichophyton mentagrophytes in Iran, Harboring Mutations in the Squalene Epoxidase (SQLE) Gene

Simin Taghipour et al. Infect Drug Resist. .

Abstract

Introduction: Trichophyton mentagrophytes and T. interdigitale are important causative agents of superficial mycoses, demonstrating emergent antifungal drug resistance. We studied the antifungal susceptibility profiles in Iranian isolates of these two species.

Methods: A total of 96 T. interdigitale and 45 T. mentagrophytes isolates were subjected to molecular typing by ribosomal ITS region. Antifungal susceptibility profiles for terbinafine, griseofulvin, clotrimazole, efinaconazole, luliconazole, amorolfine and ciclopirox were obtained by CLSI broth microdilution method. The squalene epoxidase (SQLE) gene was subjected to sequencing for mutations, if any, in isolates exhibiting elevated MICs for terbinafine.

Results: Luliconazole and efinaconazole showed the lowest MIC values against T. mentagrophytes and T. interdigitale isolates. There were five isolates with terbinafine MICs ≥32 µg/mL in our sample. They belonged to T. mentagrophytes type VIII and harbored two alternative SQLE gene sequence variants, leading to Phe397Leu and Ala448Thr or Leu393Ser and Ala448Thr substitutions in the enzyme. All terbinafine resistant strains could be inhibited by luliconazole and efinaconazole.

Conclusion: This study documented a step in the global spread of resistance mechanisms in T. mentagrophytes. However, treatment alternatives for resistant isolates were available.

Keywords: Iran; SQLE; Trichophyton mentagrophytes; antifungal drug resistance; terbinafine.

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Conflict of interest statement

The authors declare that they have no competing interests in this work.

References

    1. De Hoog GS, Dukik K, Monod M, et al. Toward a novel multilocus phylogenetic taxonomy for the dermatophytes. Mycopathologia. 2017;182:5–31. doi: 10.1007/s11046-016-0073-9 - DOI - PMC - PubMed
    1. Hay RJ. Dermatophytosis (ringworm) and other superficial mycoses. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. Eighth ed. Philadelphia, PA: Elsevier; 2015:2985–2994.
    1. Gupta AK, Foley KA, Versteeg SG. New antifungal agents and new formulations against dermatophytes. Mycopathologia. 2017;182(1–2):127–141. doi: 10.1007/s11046-016-0045-0 - DOI - PubMed
    1. Verma S, Madhu R. The great Indian epidemic of superficial dermatophytosis: an appraisal. Indian J Dermatol. 2017;62(3):227. doi: 10.4103/ijd.IJD_206_17 - DOI - PMC - PubMed
    1. Singh A, Masih A, Khurana A, et al. High terbinafine resistance in Trichophyton interdigitale isolates in Delhi, India harboring mutations in the squalene epoxidase gene. Mycoses. 2018;61(7):477–484. doi: 10.1111/myc.12772 - DOI - PubMed

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