A study on the resistance of antibiotic and plasmid profile of Leuconostoc spp. isolated from carrot

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-B2C2, 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.