Abstract
Problem statement: Dermatophytes have developed resistance to
the existing antifungal antibiotics. As a part of our continuous search we had
isolated, identified and characterized actinomycetes from the halophilic environment
having antagonistic activity against the dermatophytes namely Trichophyton, Microsporum
and Epidermophyton. Approach: Actinomycetes were isolated from
the soil sample collected from the Ennore saltpan region, Chennai, India and screened
for antidermatophytic secondary metabolite production by well diffusion method.
Four dermatophytes Trichophyton rubrum [MTCC 3272], Trichophyton mentagrophytes
[MTCC 7687], Microsporum gypseum [MTCC 2819] and Epidermophyton floccosum [MTCC
7880] were used to study its susceptibility to the isolated actinomycetes. Actinomycetes
which showed antidermatophytic activity were subjected to cultural characterization
with respect to aerial and substrate mycelia color, diffusible and melanin pigment
production and the growth of the organisms on different media. Further the micro
morphological characteristics such as spore surface ornamentation and spore chain
morphology determined by Scanning Electron Microscopic (SEM) analysis also suggested
that the isolates belonged to the genus Streptomyces. The isolates were also tested
for utilization of various carbon and nitrogen sources, degradation of complex
compounds, sensitivity to antibiotics and inhibitory compounds. Results:
All the 3 isolates exhibited different cultural and morphological characteristics.
Based on the cultural characters and morphology they were assigned to the genus
Streptomyces. The three isolates produced an inhibition zone of 30-31 mm on an
average, utilized a wide range of carbon and nitrogen sources, degraded almost
all the complex compounds and exhibited a broad spectrum of antibiotic resistance.
They were designated as Streptomyces sp. DKDVIT1, Streptomyces sp. DKDVIT2 and
Streptomyces sp., DKDVIT3. Conclusion: The Streptomyces sp. isolated
from the Ennore saltpan of Bay of Bengal exhibited potential antidermatophytic
activity. The extraction and characterization of secondary metabolites from these
Streptomyces may be used as a lead compound/therapeutic agent for dermatophytosis.