ANTIBIOTICS PRODUCING BACTERIA ISOLATED FROM FARMLANDS

Abstract

The need for new antibiotics has been highlighted recently with the increasing pace of emergence of drug resistance pathogens. Emerging strains of bacteria resistant to most advanced antibiotics have become issues of very important public health concern. Modification of existing antibiotics with the addition of side chains or other chemical group and genomics based drug targeting have been the preferred method of drug development at the corporate level in recent years. In this regard, soil samples were collected from farmlands located in Ibadan in Oyo state, Ago – Iwoye, and Ikenne in Ogun state, Nigeria. Two putative Streptomyces strains and Bacillus strains isolated from the 16 selected farmland soils were characterized and assessed for antibiotic production and activity against a wide range of bacteria including Klebsiella pneumonia, Serratia marscens, Proteus vulgaris, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. The extracts of the putative obtained from Streptomyces somaliensis, Streptomyces anulatus, Bacillus megaterium, and Bacillus subtilis showed activities against minimum of 3 and maximum of the 4 of the 7 tested bacteria. Inhibition zones were found to range between 2.0 - 25.0 mm diameters at a concentration of 1ml. The minimum inhibitory concentrations (MICs) of the crude extracts against the tested organisms ranged from 50% and above. Bacillus megaterium, and Streptomyces somaliensis were found to inhibit all the pathogenic bacteria, while S. anulatus was unable to inhibit Proteus vulgaris and Staphylococcus aureus, and B. Subtilis was unable to inhibit Enterococcus faecalis.