ABSTRACT

Soil is the major repository of microorganism that produce antibiotics. Clinically useful antibiotics have been isolated from several groups of soil microorganisms including bacteria (Streptomyces sp. Bacillus sp.). Bacillus and actinomycetes are the most abundant microorganisms present in soil and inhibit the growth of other microorganisms present in soil and inhibit the growth of other microorganism. In this research, Ten samples of soil collected from a cultivated Farmland within the premises of College of Crop and Soil Sciences were screened for antibiotic, producing microorganisms. Ten fold serial dilutions of the soil samples were prepared and inoculated on Nutrient Agar and Saboraud Dextrose Agar. A total number o Twenty three isolates were recovered. Ten of the total isolates were subcultured on Nutrient agar and incubated at 37OC for 24hrs. Out of these ten isolates four are Micrococcus, four Bacillus species and two Actinomycetes were obtained. Five different isolates was tested against four test organisms namely; Pseudomonas aeruginosa (ATCC ® 278 53TM), Staphylococcus aureus (ATCC® 25923 TM) Escherichia coil (ATCC®28735TM) and Mj.'cohacterium smegmauis (ATCC®28735TM) to observe their antimicrobial activity against the test organisms. One of the isolates (CCSSH1 ) that is actinomycete was able to inhibit growth of Staphylococcus aureus with a clear inhibition range with a clear inhibititon range of 0 — 14 mm, which indicates an antibacterial activity against Saureus while others showed no antimicrobial activity against the test organisms. This shows that the screening and isolation of CCSSH1from this study area may contribute to the discovery of new antibiotics with further extraction and purification of the isolate.