Isolation and identification of metal-tolerant and antibiotic-resistant bacteria from soil samples of Cachar district of Assam, India

The present study aims to assess the physicochemical properties and prevalence of microbial communities in soils samples collected from different locations of Cachar district, Assam, India. Bacterial communities in the soil were screened by morphological, biochemical and 16S rDNA sequence analysis and were identified as Bacillus megaterium, Bacillus cereus, Pseudomonas aeruginosa and Chromobacterium pseudoviolaceum. High concentrations of toxic metals negatively affect bacterial growth, and therefore, the minimum inhibitory concentration of isolated bacteria was determined against Cd, Pb, Fe and Cu by agar dilution technique. Co-resistance of antibiotic was also determined, which demonstrated that most of the metal-tolerant isolates were resistant to Methicillin and Penicillin. However, P. aeruginosa showed resistance to other antibiotics such as Cefdinir, Ampicillin, Kanamycin, Rifampicin and Vancomycin. The development and evolution of antibiotic resistance in soil bacteria occurs very likely naturally as a result of unethical and non-scientific disposal of toxic substances and industrial discharge, which also includes heavy-metal effluents and other clinical by-products. Therefore, pragmatic measures must be taken to limit the spread of antimicrobial resistance across the environment and to reduce the incidence of healthcare-associated infections.