title: Terbinafine susceptibility and genotypic heterogeneity in clinical isolates of Trichophyton mentagrophytes by random amplified polymorphic DNA (RAPD).
abstract: OBJECTIVE
  The four RAPD systems tested in the present study have aimed at investigating DNA fingerprinting of Trichophyton mentagrophytes strains and the correlation between genotyping and antifungal susceptibility to terbinafine.
  
  
  METHODS
  Twenty-nine clinical isolates of T. mentagrophytes were recovered from patients suspected of having active dermatophytosis who were referred to the laboratory of medical mycology department in Tehran university. Then, they were subjected to conventional examination by performing direct microscopic examination, culture on primary media, physiological tests.
  
  
  METHODS
  The in vitro antifungal susceptibility of twenty-nine T. mentagrophytes isolates against terbinafine was evaluated by modified agar dilution method to determine the minimum inhibitory concentration (MIC). Twenty-one sensitive and eight resistant to terbinafine, were submitted to RAPD using 4 decamer primers (A, B, C, D) with the purpose of encountering a genetic marker to terbinafine sensibility and resistance. The UPGMA-Jaccard's correlation coefficient was used to build up dendogram that could represent clusters of similarity. According to their correlation coefficient, the samples were classified as much related (100%), moderately related (80%) and unrelated (<70%).
  
  
  RESULTS
  All amplifications revealed distinct polymorphic bands and a total of 34 band positions was scored (0/1) for the 4 primers tested. Genetic distances between each of the isolates were calculated and cluster analysis was used to generate a dendrogram showing relationships between them. The combined dendrogram at an average similarity value of 65% grouped all strains into 2 (A, B) groups corresponding to their susceptibility reactions to terbinafine. All susceptible samples were properly grouped, but a few numbers of resistant isolates were also included. Nevertheless, further biochemical and molecular biological studies will be required to fully elucidate the point that resistance might be the result of a mutation in the gene encoding squalene epoxidase in T. mentagrophytes.
  
  
  CONCLUSIONS
  This study proved efficacy of applying RAPD molecular technique to complement traditional mycological culture and drug susceptibility tests for accurate and appropriate management of recurrent dermatophytosis and highlights the need for newer antifungals that can combat the emergence of terbinafine-resistant T. mentagrophytes strains.
authors: Department of microbiology, Karaj branch, Islamic Azad university, Karaj, Iran. Electronic address: alipoor_fereshte@tahoo.com.
authors: M
authors: M
authors: Alipour
authors: Department of microbiology, Iran university of medical sciences and health services, Tehran, Iran.
authors: N A
authors: NA
authors: Mozafari
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D004271:DNA, Fungal / Q000032:analysis; D025141:Drug Resistance, Fungal / Q000235:genetics; D018740:Genetic Heterogeneity; D006801:Humans; D008826:Microbial Sensitivity Tests; D016533:Mycological Typing Techniques / Q000379:methods; D009281:Naphthalenes / Q000494:pharmacology*; D011110:Polymorphism, Genetic; D019105:Random Amplified Polymorphic DNA Technique; D000077291:Terbinafine; D014005:Tinea / Q000235:genetics / Q000382:microbiology; D014249:Trichophyton / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000935:Antifungal Agents; D004271:DNA, Fungal; D009281:Naphthalenes; D000077291:Terbinafine
keywords: ADN polymorphe amplifié (RAPD); Dermatophytosis; Random amplified polymorphic DNA technique; Terbinafine; Trichophyton mentagrophytes