Abstract

In the present study, a total of 56 isolates were isolated from different root vegetables. Out of these, 17 isolates were identified as Leuconostoc spp. All the 17 isolates were checked for antibiotic sensitivity against different antibiotics. Results revealed that majority of the isolates were resistant to Penicillin G, Vancomycin, Oxacillin and Ceftazidime. Four isolates (S-9, S-13, S-37 and S-42) were resistant to methicillin. However, all the isolates were highly sensitive to Imipenum. Carbenicillin and Amoxicillin sublactam showed antibacterial sensitivity against all the isolates except S-13 and S-B₂C_2, respectively. Electrophorogram revealed that among the different 17 Leuconostoc isolates, S-B₂C₂ showed the presence of multiple plasmids (six) corresponding to the molecular weights of 1.5, 1.9, 2.0, 2.6, 3.2 and 10 kb, respectively. Endonuclease restriction analysis study was carried out with purified plasmid using four endonucleases (Alu I, Bam HI, Hae III and Hind III). Treatment with Alu I resulted in the disappearance of all the 6 plasmid bands, indicating complete digestion of the plasmids. Restriction analysis of plasmid DNA of isolate S-B₂C₂ revealed complete digestion of two plasmids (2.6 and 1.5 kb) when treated with Hind III. However, a new band of molecular weight equivalent to 1.7 kb did appear. Data presented in the paper indicates the multiple plasmid availability in bacteria and their diversity in response to restriction sites available on them.

Key words: Antibiotic resistance, plasmid, restriction digestion, root vegetables.