ABSTRACT

A total of 28 strains of Salmonella, Pseudomonas and Escherichia coli isolated from cultures of stool, urine and wound were tested for their susceptibility to various antimicrobial names agents. All the strains possessed resistance to erythromycin and tetracycline. Nineteen Salmonella isolates were susceptible to chloramphenicol and gentamycin. All the Pseudomonas and Escherichia coli isolates were resistant to chloramphenicol and cioxacillin while one Pseudomonas spp and three Escherichia coli isolates were sensitive to gentamycin. The antibiotic resistance determinants in each strain were encoded by plasmid. Plasmidmediated antibiotic resistance strains were detected by Agarose gel electrophoresis analysis with Lambda Hind 111 digest used as the molecular weight marker. These isolates were typed by plasmid profile analysis according to their different molecular weights. Several similar and t distinct profiles were identified for most resistant and sensitive isolates. It appeared that a single strain containing a plasmid conferring multiple drug resistance emerged within the bacterial population and was able to adapt and to survive the challenges of antibiotics as they were introduced into < clinical medicine. Therefore the acquisition of plasmid have greatly | contributed to the rapid spread of antibiotic resistance genes in the i bacterial population.