Screening for antibacterial producing bacteria isolated from soil in Keffi, Nasarawa, State, Nigeria

Abstract

Antibiotics are secondary metabolites that inhibit other competing cells to give competitive advantage to the microorganisms that produce them. This study is aimed at screening for antibacterial producing bacteria isolated from soil in Keffi. Standard microbiological methods were used in isolation and screening for antimicrobial of activity of crude extracts. Molecular identification of bacteria isolated were carried out using 16srRNA method. The antibacterial activity was carried out using agar well diffusion methods. The highest bacteria were Isolated from maize rhizosphere (90.0%) and the least was from groundnut rhizosphere (50.0%). Bacterial isolated and identified using 16srRNA were Pseudomonas fluorescens, Pseudomonas antarctica, Bacillus megaterium and Acetobacter aceti. The screening for antimicrobial producing bacteria showed that bacterial with laboratory code Gn3 (Pseudomonas fluorescens) showed activity against E. coli (8.57±1.01 mm), S. typhi (5.10±0.11 mm) and S. aureus (6.12±0.32 mm). Ma1 had activity against E. coli (8.57±1.01 mm), S. typhi (5.10±0.11 mm) and S. aureus (6.12±0.32 mm). Ma2 had activity against E. coli (7.56±1.33 mm) and S. typhi (4.54±0.34 mm) and Rc2 had activity only against S. aureus (12.12±0.98 mm) The Antibacterial activity of bacteria isolated and grown in complex medium with nitrogen source revealed that Pseudomonas fluorescens showed activity against the test organism E. coli (14.03±1.06mm), S. typhi (9.11±1.11mm) and S. aureus (5.12±1.02 mm). It was observed in this study that bacterial isolated from soil in Keffi were able to produce substance that that inhibit other bacterial.