Introduction: Resistance of pathogenic organisms to countenance antibiotics has become a worldwide problem with serious consequences on the treatment of infectious diseases. The aim of this study was to evaluate antibiotic resistance and also the detection of transferred antibiotic resistance by plasmid in clinical Proteus isolates.

Materials and methods: A total of 250 urine samples were collected from patient suffered from urinary tract infection (UTI), and cultured on blood agar and MacConkey's agar. Positive cultures were diagnosed by routine microbiological and biochemical tests. Antibiotic susceptibility test was performed by disc diffusion method. The minimum inhibitory concentration (MIC) was evaluated by agar dilution method, and also antibiotic resistance mediated by plasmid was determined using transformation of plasmids to plasmid free Escherichia coli ATCC 25922 as competent cell.

Results: Among 200 samples, 120 samples (60%) were collected from female and 80 samples (40%) were isolated from males. Out of 25 species (12.5%) were diagnosed as Proteus. Al isolates were resistant to ampicillin (maximum frequency), only 16% of isolates were resistance to amikacin (minimum resistance). Totally, 66.66% of Proteus isolates harbored plasmids. All plasmid containing P. mirabilis isolates were able to transferred resistance to amoxicillin, ampicillin, while rate of resistance to other antibiotics were as amikacin (88%), gentamycin (72%), tetracycline (50%), tobramycin (48%), ceftazidime, cefotaxime (32%) and ciprofloxacin (22%).