Francisca Omolara Ibitoye, Tolulope Racheal Elehinafe, Babatunde Oluwaseun Ibitoye
Glyphosate has been a widely used herbicide for close to half a century to control weeds through a biochemical process by acting as an enzymatic inhibitor in the shikimate pathway of aromatic amino acid synthesis. The aim of this work is to assess the impact of glyphosate usage in farms on the bacteria ecosystem and its influence on the development of antibiotic resistance in the bacteria exposed to it.
Four soil samples were collected at four different locations. Three were collected at a farm in Owo in Ondo state, where the herbicide is frequently used to control weeds (samples A, B, and C), while sample D was collected at a nearby farm with no use of the herbicide in the past. The organisms were cultured using the serial pour plate method, bacteria count was enumerated and the pure culture was obtained. The bacteria were identified using biochemical methods. Antibiotic sensitivity testing using common antibiotics was used against the bacteria isolated. The result showed a count of 6.6 ± 0.02 × 105 cfu/gm for sample A, 5.9 ± 0.01 × 105 cfu/gm for sample B, 4.9 ± 0.01 × 105 cfu/gm for sample C, and 7.0 ± 0.02 × 105 cfu/gm for sample D (control). The identified organisms in contaminated soil are Bacillus cereus, Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Staphylococcus aureus, and Flavobacterium lutescens, while the organisms found in control soil are Clostridium botulinum and Bacillus subtilis. Most of the isolated organisms were susceptible to most antibiotics except Staphylococcus aureus and amoxicillin, which was the most common antibiotic resisted by most bacteria. Glyphosate has selective pressure on the state of biomass and bacteria in an area exposed to it, and it could affect antibiotic sensitivity to some degree. However, this may need further evaluation.