Abstract

Diseases caused by pathogenic microorganism infections such as diarrhoea, gastrointestinal and urogenital diseases, and wound infections, are on the rise and pose a threat to human health as multidrug-resistant pathogens arise. This study assessed the antibacterial activity of Streptomyces species isolated from soil at Rivers State University, Port Harcourt. A total of ten separate surface soil samples were aseptically collected at random from five different locations. Enumeration, isolation and screening of probable Streptomyces species for antibacterial activity were conducted using standard microbiological techniques. The mean Total Streptomyces count ranged from 0±0.00 x10³ CFU/g to 3.1±0.14×10³ CFU/g. Mean range of percentage distribution for the soil samples was 0 to 26.7%. Presumptive characterization and identification revealed that all the 15 distinct isolates exhibited typical features that fitted the genus Streptomyces. Primary screening was done using the Perpendicular Cross-streak technique. Secondary screening was performed using the Well in Agar method with Ethyl acetate extracts of Streptomyces isolates at a concentration of 50mg/ml. Results shows that majority of the Streptomyces extracts exhibited antagonistic activity against both test organisms; Staphylococcus aureus ATCC 12600 and Salmonella typhimurium CCARM 8256 as evident with moderate zones of inhibition. The partial nucleotide sequences of 16S rRNA gene led to identifying the 5 most potent isolates as various strains of Streptomyces species. Overall, the findings of this study has contributed to the discovery that soils at Rivers State University support and provide habitat for potential antibiotic generating Streptomyces. To maximise the production of antibiotic chemicals produced by Streptomyces isolates, fermentation conditions such as growth media, pH, temperature, and other critical fermentation parameters should be optimized.