B Bacteri a iologic after s cal stu subjec udy on ction to Prote o prob eus mir biotic rabilis s

       For the isolation of Proteus mirabilis, 85 samples were collected from different locations in Baghdad governorate. These samples include 20 samples of urine, 45 samples of wounds, and 20 samples of chicken and meat. From the overall samples a total of 146 isolates were obtained. These isolates were identified according to their morphological,microscopical characteristic and biochemical tests. Results of identification showed that 15 of the total isolates were belonged to P. mirabilis. These results were confirmed by identification using Api20E system.      Pathogenecity of local isolates of P. mirabilis were studied by investigating several virulence factors of these isolates of P. mirabilis which include invasion and adhesion ability and protease production. Results showed that most of these isolates invaded uroepithelial cells with average range between 1 and 20 bacterial cell/uroepithelial cell, have the adhesion ability with average range between 30 and 55 acteria/uroepithelial cell, and able to produce protease with specific activity between 14.5 and 0.121 U/mg protein. Among these different isolates, the isolate  P. mirabilis P15 from urine was selected for further studies because it was the most virulent. Antibiotic susceptibility of P. mirabilisP15 against different antibiotics was examined. Results showed that this isolate was resiststant to Tetracycline, Cefotaxime, Cefepime, Amikacinand, Ciprofloxacin, while it was sensitive to other antibiotics studied. Plasmid profile of P. mirabilis P15 was detected by extraction of plasmid DNA according to alkaline lysis method.     Results of electrophoresis on agarose gel showed that this isolate harboring two plasmids differ in their size conferring to cefotaxime and Amikacin resistance, according to the results of curing experiment by using ethidium bromide. Another part of this study was focused on the effect of probiotic of lactic acid bacteria on growth and virulence factors of P. mirabilis P15.This was achieved first by re-identification of an isolate of Lactobacillus acidophilus, then probiotic of fresh culture of this isolate was used to study its effect on P. mirabilis P15. Results showed that invasiveness, adhesion, and protease production by P. mirabilis P15 were highly influenced and decreased after treatment with probiotic, and the effect was increased with the increase of probiotic concentration.