Molecular Identification and Antifungal Susceptibility Patterns of Clinical Dermatophytes Following CLSI and EUCAST Guidelines

Dermatophytes are associated with superficial infections in humans worldwide. The aim of the present study was to determine the species distribution and susceptibility patterns of clinical dermatophytes. Samples received for routine mycological processing from 124 suspected cases attending a dermatologic clinic in a tertiary care hospital were included in the study. On direct microscopy, 74.1% (92/124) were positive and 53.2% (66/124) grew on culture. The isolates were comprised of Trichophyton interdigitale (56%) followed by Trichophyton tonsurans (25.7%), Trichophyton rubrum (7.5%), Trichophyton violaceum (4.5%), Microsporum gypseum (4.5%), and Trichophyton verrucosum (1.5%). Conventional mycological identification was concordant with ITS sequencing except for T. mentagrophytes. High minimum inhibitory concentration (MIC) values (geometric mean, >1 µg/mL) were observed for T. tonsurans and T. rubrum to terbinafine and griseofulvin. This study highlights the shift in epidemiology from T. rubrum to T. interdigitale. It also raises a concern of high MICs of terbinafine and griseofulvin among our isolates. Surveillance of antifungal susceptibility patterns can provide clinicians with local MIC data that can further aid in guiding better management in relapse cases of dermatomycosis.

[1]  R. Zemni,et al.  Relationship Between Phenotypic and Genotypic Characteristics of Trichophyton mentagrophytes Strains Isolated from Patients with Dermatophytosis , 2017, Mycopathologia.

[2]  Yoshiki Matsuda,et al.  Efficacy Coefficients Determined Using Nail Permeability and Antifungal Activity in Keratin-Containing Media Are Useful for Predicting Clinical Efficacies of Topical Drugs for Onychomycosis , 2016, PloS one.

[3]  M. Afshari,et al.  Antifungal susceptibility and virulence factors of clinically isolated dermatophytes in Tehran, Iran , 2016, Iranian journal of microbiology.

[4]  P. Sharma,et al.  Determination of minimum inhibitory concentrations of itraconazole, terbinafine and ketoconazole against dermatophyte species by broth microdilution method , 2015, Indian journal of medical microbiology.

[5]  S. Chandra,et al.  Dermatophytes: Diagnosis of dermatophytosis and its treatment , 2015 .

[6]  C. Lass‐Flörl,et al.  Evaluation of a Modified EUCAST Fragmented-Mycelium Inoculum Method for In Vitro Susceptibility Testing of Dermatophytes and the Activity of Novel Antifungal Agents , 2015, Antimicrobial Agents and Chemotherapy.

[7]  B. Piraccini,et al.  Onychomycosis: A Review , 2015, Journal of fungi.

[8]  Shukla Das,et al.  Clinico-Mycological Study of Dermatophyte Toenail Onychomycosis in New Delhi, India , 2015, Indian journal of dermatology.

[9]  S. Sheikh,et al.  Topical Delivery of Lipid Based Amphotericin B Gel in the Treatment of Fungal Infection: A Clinical Efficacy, Safety and Tolerability Study in Patients , 2014 .

[10]  G. Indira.  In Vitro Antifungal Susceptibility Testing of 5 Antifungal Agents against Dermatophytic Species by CLSI (M38-A) Micro Dilution Method , 2014 .

[11]  P. Sharma,et al.  Epidemiological studies on Dermatophytosis in human patients in Himachal Pradesh, India , 2014, SpringerPlus.

[12]  K. Makimura,et al.  In vitro susceptibility of dermatomycoses agents to six antifungal drugs and evaluation by fractional inhibitory concentration index of combined effects of amorolfine and itraconazole in dermatophytes , 2014, Microbiology and immunology.

[13]  T. Thirunalasundari,et al.  Epidemiology of dermatophytosis in and around Tiruchirapalli, Tamilnadu, India , 2012 .

[14]  P. Vandeputte,et al.  Antifungal Resistance and New Strategies to Control Fungal Infections , 2011, International journal of microbiology.

[15]  M. Vernez,et al.  Efficacious Treatment of Non-Dermatophyte Mould Onychomycosis with Topical Amphotericin B , 2012, Dermatology.

[16]  A. Shrivastav,et al.  The occurrence of keratinophilic fungi in selected soils of Ladakh (India) , 2010 .

[17]  M. Moazeni,et al.  Onychomycosis in Tehran: mycological study of 504 patients , 2010, Mycoses.

[18]  M. Chadeganipour,et al.  Study of onychomycosis in Isfahan, Iran , 2010, Mycoses.

[19]  S. Mulla,et al.  A study of superficial mycosis in South Gujarat region. , 2010 .

[20]  R. Pal,et al.  Clinico-etiologic correlates of onychomycosis in Sikkim. , 2009, Indian journal of pathology & microbiology.

[21]  Maria R R Silva,et al.  In vitro susceptibility testing of dermatophytes isolated in Goiania, Brazil, against five antifungal agents by broth microdilution method. , 2009, Revista do Instituto de Medicina Tropical de Sao Paulo.

[22]  R. Barton,et al.  Identification of dermatophytes by sequence analysis of the rRNA gene internal transcribed spacer regions. , 2008, Journal of medical microbiology.

[23]  Clinical,et al.  Reference method for broth dilution antifungal susceptibility testing of filamentous fungi : Approved standard , 2008 .

[24]  D. Denning,et al.  EUCAST DEFINITIVE DOCUMENT E.DEF 9.1: Method for the determination of broth dilution minimum inhibitory concentrations of antifungal agents for conidia forming moulds , 2008 .

[25]  A. K. Borthakur,et al.  A clinico-epidemiological study of dermatophytoses in Northeast India. , 2007, Indian journal of dermatology, venereology and leprology.

[26]  C. Janaki,et al.  Trichophyton rubrum the predominant etiological agent in human dermatophytoses in Chennai, India , 2007 .

[27]  Daniel de Assis Santos,et al.  Evaluation of susceptibility of Trichophyton mentagrophytes and Trichophyton rubrum clinical isolates to antifungal drugs using a modified CLSI microdilution method (M38-A). , 2007, Journal of medical microbiology.

[28]  R. Kaur,et al.  A five-year survey of onychomycosis in New Delhi, India: Epidemiological and laboratory aspects , 2007 .

[29]  B. Khanal,et al.  Onychomycosis in eastern Nepal. , 2006, Nepal Medical College journal : NMCJ.

[30]  P. Wormald,et al.  An assessment of the efficiency of fungal DNA extraction methods for maximizing the detection of medically important fungi using PCR. , 2006, Journal of microbiological methods.

[31]  Aditya K. Gupta,et al.  In vitro susceptibility testing of ciclopirox, terbinafine, ketoconazole and itraconazole against dermatophytes and nondermatophytes, and in vitro evaluation of combination antifungal activity , 2003, The British journal of dermatology.

[32]  S. Singh,et al.  Profile of dermatophyte infections in Baroda. , 2003, Indian journal of dermatology, venereology and leprology.

[33]  S. Singh,et al.  Comparative study of different microscopic techniques and culture media for the isolation of dermatophytes. , 2003, Indian journal of medical microbiology.

[34]  B. Elewski,et al.  A large-scale North American study of fungal isolates from nails: the frequency of onychomycosis, fungal distribution, and antifungal susceptibility patterns. , 2000, Journal of the American Academy of Dermatology.

[35]  M. Ghannoum,et al.  Antifungal Susceptibility Testing of Dermatophytes: Establishing a Medium for Inducing Conidial Growth and Evaluation of Susceptibility of Clinical Isolates , 2000, Journal of Clinical Microbiology.

[36]  B. Elewski.  Onychomycosis. Treatment, quality of life, and economic issues. , 2000, American journal of clinical dermatology.

[37]  B. Elewski,et al.  Onychomycosis: Pathogenesis, Diagnosis, and Management , 1998, Clinical Microbiology Reviews.

[38]  A. Padhye,et al.  Dermatophytes: gross and microscopic. , 1996, Dermatologic clinics.

[39]  R. Summerbell,et al.  The dermatophytes , 1995, Clinical microbiology reviews.

[40]  T. Menon,et al.  Effect of socio-economic status on the prevalence of dermatophytosis in Madras. , 1995, Indian journal of dermatology, venereology and leprology.

[41]  T. White.  Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics , 1990 .