[Plasmid profile of pseudomonas aeruginosa and its relation with antibiotic resistance in hospital isolates]

ABSTRACT

P. aeruginosa is one of the causes of nosocomial infections with an unusual resistance to antibiotics. The source of resistance in this bacterium may be chromosomal or plasmid. The aim of the present study was to investigate the antibacterial susceptibility patterns with the presence of plasmids in P. aeruginosa isolates. In this study, 140 P. aeruginosa isolates were collected from hospitals in Urmia/Iran. The susceptibility patterns were determined against antibiotics. Plasmids were extracted by alkaline lysis method, electrophoresed and investigated by a UV transilluminator. Single digestion of plasmids with EcoR1 and HincII were performed and the restriction patterns were compared using a ladder. The rates of resistances to antibiotics were as follows gentamicin 49.3%, cephalothin 99.3%, ticarcillin 100%, ceftizoxime 79.3%, co-trimoxazole 97.7%, amikacin 35%, carbenicillin 67.1%, ceftriaxone 65.7%, ciprofloxacin 58.6%, piperacillin 52.8%, imipenem 1.4%, kanamycin 65.7%, ofloxacin 72.1% and ampicillin 100%. In Whole, 65.7% of isolates harbored plasmids. Restriction enzyme analysis of plasmids showed unique pattern for all of plasmid positive isolates. All the plasmid positive isolates were resistant to ceftriaxone and kanamycin. The plasmid source of resistance to ceftriaxone was proved by plasmid elimination and transformation in E. coli DHS alpha and the plastid source of resistance to kanamycin was proved by plasmid elimination. Also there was a significant correlation between the presence of plasmid in isolates and resistance to some of antibiotics. There was a high frequency of plasmids in P. aeruginosa isolates, indicating that plasmids have an important role in transferring of resistance genes in this bacterium