Antibiotic Resistance, Plasmid and RAPD Profiles of Multidrug-resistant Coliform Bacteria Isolated from Sewage Samples of Ghaziabad City, India

The aim of the present work is to study the antibiotic resistance, plasmid and RAPD profiles of the multidrug resistant (MDR) Coliform bacteria isolated from raw and treated sewage of Ghaziabad city, India. The MDR bacterial population in the raw and treated sewage constituted 7.5% and 19.1% of the total Coliform bacteria respectively. Five MDR Coliform bacteria (2 from raw and 3 from treated sewage) were isolated and identified as Enterobacter spp. by morphological and biochemical tests. These MDR strains were resistant to most of the commonly used antibiotics including amikacin. Plasmid isolation studies showed that all MDR strains harboured a single plasmid of approximately 54.4 kb size. Random amplification of polymorphic DNA (RAPD) analysis of genomic DNA produced three RAPD profiles and showed variation between the raw and treated sewage isolates. Further, MDR strain R1 that was resistant to all 16 antibiotics tested showed plasmid-mediated resistance which was confirmed by plasmid curing study.