Comparison of the activities of four antifungal agents in an in vitro model of dermatophyte nail infection

Abstract

Background:Onychomycosis is a difficult condition to treat and cure rates are disappointing. Moreover fungicidal action of antifungal agents in NCCLS assays and their rapid accumulation in nails in vivo are not compatible with the duration of treatment.Aims:This study aimed to find the effectiveness of 4 different antifungal agents in an in vitro model with some similarities to in vivo conditions.Materials and Methods:Strains of Trichophyton rubrum I-III, Trichophyton mentagrophytes (usual form), Trichophyton mentagrophytes 73, Epidermophyton Flucosom, Microsporum Canis, and Trichophyton Schoenleini which were isolated from the nails of patients, were hired. Inocula suspensions were prepared from 7 to 14 day-old cultures of dermatophytes. Antifungal agents including fluconazole, ketoconazole, terbinafine, and griseofulvin were obtained as standard powders. For each antifungal agent, initial MIC was calculated by registering the optical density for 10 two-fold serially diluted forms which was incubated with diluted fungal suspensions with RPMI 1640. Human nail powder inoculated with different strains and incubated in RPMI 1640 and different concentrations of antifungal drugs for 4 weeks. Final MIC at different steps of 1, 2, 3 and 4 weeks were investigated.Results:The final MIC that resulted from the incubation of dermatophytes with nail powder was much more than the initial which was concluded from conventional MIC assay. Terbinafine had the lowest rate of initial and final MICs.Conclusion:The model described here may present more similar conditions to clinical fungal infections; therefore the results such as MIC may be more helpful for hiring the most effective antifungal agent.

Prevalence of Dermatophytosis and Antifungal Activity of Ethanolic Crude Leaf Extract ofTetradenia ripariaagainst Dermatophytes Isolated from Patients Attending Kampala International University Teaching Hospital, Uganda

“…The MIC and MFC of terbinafine were also generally less for T. tonsurans (0.0078 and 0.0156 mg/ml), followed by T. mentagrophyte (0.0078 and 0.0313 mg/ml) while M. audouinii had 0.03 3 and 0.0625 mg/ml. This finding is similar to the findings of [36, 37] against similar organisms when using terbinafine. Terbinafine causes changes in the fungal cell permeability with consequent modification of the cell structure which also causes hyphae to become parched and wrinkled when viewed under an electron microscope.…”

Molecular Characterization and In Vitro Antifungal Susceptibility of 316 Clinical Isolates of Dermatophytes in Iran

“…In the current study, for all tested strains, TER had lowest MICs, followed by ITC and GRZ, whereas FLU did not exert inhibitory effects. Up until now, few reports have evaluated in vitro activity of some antifungal agents against dermatophyte species in Iran [35][36][37][38]. Our results show similarity to some previous studies [9,[39][40][41][42][43] and also in contrast to some other reports [38,44].…”

A Hydroxypropyl Chitosan (HPCH) Based Medical Device Prevents Fungal Infections: Evidences from an In Vitro Human Nail Model

“…Keratin is not only a nutrient to the dermatophytes but it is also the up-regulator for some putative virulence factors [5]. The importance of keratin for mimicking the in vivo situation was the object of various studies [9][10][11], where the medium was supplemented with pulverized nail clippings as the keratin source [5]. Lusiana et al [5] reviewed the limitations of the current in vitro tests and proposed a novel model of infected nail plate using a keratin film made of human hair keratin, a largely available material, and compared it with bovine hoof, obtaining equivalent responses following treatment with antifungal preparations.…”