Screening for Antimicrobial Potency of Microorganisms Isolated From Soil within the Premises of Federal University, Oye-Ekiti, against Test Microorganisms

Abstract

The search for novel antimicrobials from soil has been on for a very long time and is still on. In a similar search, this study aimed at screening soil samples collected within the premises of Federal University, Oye-Ekiti, for microorganisms with antimicrobial potentials against test microorganisms. Eight soil samples were collected from different sites within the university and the inherent soil bacteria, fungi and actinomycete present were isolated. The isolates were cultured using Nutrient agar, Sabouraud dextrose agar and Glycerol Yeast Extract agar. They were then screened for their antimicrobial potency against selected test microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans using Agar well diffusion method. Seven bacterial genera: Azomonas sp, Bacillus sp, Escherichia sp, Pseudomonas sp, Gluconobacter sp, Micrococcus sp, and Staphylococcus sp; five fungal genera: Aspergillus sp, Mucor sp, Rhizopus sp, Rhodotorula sp, Trichoderma sp; and one actinomycete, Actinomyces sp, were isolated. Bacillus sp. was the only bacteria found to inhibit S. aureus and Pseudomonas aeruginosa with zones of inhibition, 14 and 12 mm, respectively. Rhizopus sp. inhibited S. aureus, with a 13 mm zone of inhibition, while the other fungal isolates did not inhibit any of the test microorganisms. Actinomyces sp. inhibited all the test microorganisms at different rates; 20 mm for S. aureus and P. aeruginosa, and 18 mm for C. albicans. The actinomycetes was seen to produce more antimicrobial potency since it inhibited the growth of all the test microorganisms and showed potential for further studies.