Study of Antimicrobial Susceptibility and Plasmid Analysis of Escherichia Coli in Iran, Urmia

Twenty-five bacterial samples were isolated from buffalo faeces. twenty strains out oftwenty -five strains were identified as escherichia coli. antibiotic susceptibility tests andplasmid analysis carried on the e.coli isolates. antibiotic susceptibility tests of the isolatedstrains of e. coli were done by antibiotic disc diffusion method. the antibacterial agents wereampicillin, amoxicillin, neomycin, kanamycin, streptomycin, tetracycline, nalidixic acid,flumequine, erythromycin and enrofloxacin. plasmid dnas were extracted from each of thedrug resistant e.coli strains. all of the collected e.coli strains were resistant to ampicillin,amoxicillin, neomycin, kanamycin, streptomycin, tetracycline, nalidixic acid, flumequine,erythromycin and enrofloxacin at 90,80,100,50,100,75,75,60,100 and 35% respectively. fromthe results it was revealed that molecular size of the plasmid dnas extracted from twentydifferent drug resistant e.coli varied from 9.162 to 13.000 kb. in this investigation it wasrevealed that each of the twenty drug resistant e.coli harbored a single plasmid. it can be saidthat increasing incidence ofdrug resistance ine.coli to different antibiotics including the broadspectrum antibiotics tetracycline, nalidixic acid and ... heralds the comingtherapeutic problemin the treatment of infections cause by this micro-organism.