Starch casein agar medium supplemented with actidione and nalidixic acid was used to isolate actinomycetes from Western Ghates region of Kanyakumari, Thirunelveli, Dindigul and Nilgiri districts. Modified nutrient medium was used as the base for screening actinomycetes against pathogenic Gram positive, Gram negative and filamentous fungi.
Among 367 actinomycetes; 17.71 % showed activity against both bacteria and fungi. The highest antibacterial activity was observed against B. subtilis, 140 isolates (38.1 % ), S. aureus 128 (34.9 % ); S. epidermidis 123 (33.5 % ); P. aeruginosa 105 (28.6 % ); K. pneumoniae 88 (24 % ); Xanthomonas sp 62 (16.9 % ). Less number of actinomycetes showed activity against Erwinia, S. typhi, V. fischeri and P. vulgaris. Hundred and three isolates showed activity against B. cinerea and A. niger. Twenty five isolates revealed activity against T. simii.
Present investigation concludes that Western Ghats region of Tamil Nadu is the potential place for actinomycetes diversity. Further studying about these medically important strains from this region can be useful in identification of valuable bio-molecules.