Incidence and prevalence of dermatophytosis in and around Chennai, Tamilnadu, India

Background: Dermatophytes are group of fungi that infect keratinized tissues of human and animals. The group consist of three different genera namely, Trichophyton, Microsporum, Epidermophyton and several species within each genera. Among Trichophyton, Trichophyton rubrum is predominant, followed by various strains of Trichophyton mentagrophytes, which include both anthropophiles and zoophiles. Prevalence of dermatophytes varies with location and environmental condition. The infection is common worldwide with higher prevalence in tropical countries like India. Molecular diagnosis renders accurate identification of clinical dermatophyte isolates to species level. The main objective of this study was to determine the prevalence of dermatophytoses, isolate and identify the dermatophyte from samples of clinically suspected cases attending tertiary care centre using conventional and molecular methods.Methods: A total of 210 patients showing lesions typical of dermatophytes infection from outpatient Department of dermatology were sent to mycology unit, Department of Microbiology for the period of April 2011-March 2014 were studied. Diagnosis was confirmed by conventional and polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) technique.Results: Out of 210 samples received, tinea corporis was the predominant clinical site which was followed by tinea cruris. A total of 143 dermatophytes were isolated from the clinical samples. T. rubrum was the predominant etiological agent with 70/143 isolates and T. mentagrophytes was the second most common with 64/143 isolates. Amplification of internal transcribed spacers (ITS) was successful in all the clinical isolates by PCR and produced species specific banding pattern in RFLP using restriction enzyme Mva I.Conclusions: Among dermatophytoses, T. rubrum was the predominant etiological agent present in the whole of Chennai District and T. mentagrophytes takes the second place

Incidence and prevalence of dermatophytosis in and around Chennai, Tamilnadu, India

Background: Dermatophytes are group of fungi that infect keratinized tissues of human and animals. The group consist of three different genera namely, Trichophyton, Microsporum, Epidermophyton and several species within each genera. Among Trichophyton, Trichophyton rubrum is predominant, followed by various strains of Trichophyton mentagrophytes, which include both anthropophiles and zoophiles. Prevalence of dermatophytes varies with location and environmental condition. The infection is common worldwide with higher prevalence in tropical countries like India. Molecular diagnosis renders accurate identification of clinical dermatophyte isolates to species level. The main objective of this study was to determine the prevalence of dermatophytoses, isolate and identify the dermatophyte from samples of clinically suspected cases attending tertiary care centre using conventional and molecular methods.Methods: A total of 210 patients showing lesions typical of dermatophytes infection from outpatient Department of dermatology were sent to mycology unit, Department of Microbiology for the period of April 2011-March 2014 were studied. Diagnosis was confirmed by conventional and polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) technique.Results: Out of 210 samples received, tinea corporis was the predominant clinical site which was followed by tinea cruris. A total of 143 dermatophytes were isolated from the clinical samples. T. rubrum was the predominant etiological agent with 70/143 isolates and T. mentagrophytes was the second most common with 64/143 isolates. Amplification of internal transcribed spacers (ITS) was successful in all the clinical isolates by PCR and produced species specific banding pattern in RFLP using restriction enzyme Mva I.Conclusions: Among dermatophytoses, T. rubrum was the predominant etiological agent present in the whole of Chennai District and T. mentagrophytes takes the second place

Molecular strain typing of Trichophyton mentagrophytes (T. mentagrophytes var. interdigitale) using non-transcribed spacer region as a molecular marker

Background & objectives: Dermatophytes are keratinophilic fungi that infect keratinized tissues of human and animal origin. Trichophyton mentagrophytes is considered to be a species complex composed of several strains, which include both anthropophiles and zoophiles. Accurate discrimination is critical for comprehensive understanding of the clinical and epidemiological implications of the genetic heterogeneity of this complex. Molecular strain typing renders an effective way to discriminate each strain. The objective of the study was to characterize T. mentagrophytes clinical isolates to sub-species level using molecular techniques and non-transcribed spacer (NTS) region as marker. Methods: Sixty four T. mentagrophytes clinical isolates were identified by phenotypic methods. These were subjected to polymerase chain reaction targeting three sub-repeat elements (SREs), TmiS0, TmiS1 and TmiS2 of the NTS region. Sequence analysis of internal transcribed spacer (ITS) region of different types was also done. Results: Strain-specific polymorphism was observed in all three loci. Totally, 13 different PCR types were obtained on combining all the three SREs loci. No variation was observed in the ITS region. Interpretation & conclusions: The study described the usefulness of molecular strain typing technique for the discrimination of the T. mentagrophytes isolates. This will help for the future explorations into the epidemiology of T. mentagrophytes and its complex