Isolation and Identification of Pesticide-resistant Bacteria from Agricultural Soil in Davanagere District, Karnataka India

The extensive use of synthetic pesticides in modern agriculture has led to their persistent accumulation in soil ecosystems, posing serious risks to soil microbial diversity, fertility, and environmental health. Fipronil and Imidacloprid, widely used phenylpyrazole and neonicotinoid insecticides, are of particular concern due to their chemical stability, strong soil-binding properties, and slow degradation rates. Microbial bioremediation represents a sustainable and eco-friendly strategy for mitigating pesticide contamination by exploiting the metabolic potential of indigenous soil microorganisms. The present study aimed to isolate, identify, and evaluate pesticide-resistant bacteria from agricultural soils with a long history of pesticide application in the Davangere district of Karnataka, India. Rhizosphere soil samples were collected from multiple crop fields and subjected to enrichment using media amended with Fipronil and Imidacloprid as sole carbon sources. Five bacterial isolates—Pseudomonas aeruginosa, Escherichia coli, Azotobacter sp., Rhizobium sp., and Bacillus subtilis—exhibited sustained growth under pesticide stress, indicating metabolic tolerance and potential utilization of these compounds. Morphological and biochemical characterization confirmed isolate identities, while spectrophotometric analysis at 530 nm revealed differential growth responses, with Pseudomonas aeruginosa and Azotobacter sp. showing the highest tolerance. The results demonstrate that prolonged pesticide exposure selectively enriches soil bacteria with adaptive metabolic capabilities. These indigenous microorganisms represent promising candidates for developing microbial-based bioremediation strategies aimed at reducing pesticide residues, restoring soil health, and supporting sustainable agricultural practices.