Studies on Actinomycetes Collected from Pond Sediment Inhibiting Fish Pathogenic and Human Clinical Bacterial Isolates

摘要

The present study was conducted with a view to isolate and identifies antibiotic producing microorganisms from pond sediments against fish pathogenic and human clinical bacterial isolates. During the course of study, a total of twenty actinomycetes isolates were recovered from 10 soil samples from different regions of Satkhira and Sylhet district using starch-casein-agar and glycerol-arginine-agar media supplemented with cyclohexamide (5 μg L-1). Selected isolates from the isolation media was carried out by multiple streak method to obtain the pure cultures of selected isolates. All of the 20 isolates exhibited a range of colors including brown, creamy, yellowish and greenish in the isolation media. All of the isolates were then screened for their antagonistic activity against 4 genera of fish pathogenic and 2 genera of human clinical bacterial isolates using agar streak method. The fish pathogenic isolates belonged to Pseudomonas sp. Aeromonas sp. Flavobacterium sp. and Edwardsiella sp. whereas human clinical samples included Klebsiella sp. and Salmonella sp. isolates. All of the isolates showed remarkable antimicrobial activities against the test organisms and isolate No. N4/10 and N4/4 appeared to be the most promising ones. Several morphological, physiological and biochemical characterization tests were performed to identify the antibiotic producing soil isolates up to genus level. All the isolates were identified as actinomycetes.