O The Role of Plasmids In Pathogenicity of Locally isolated Plesiomonas shigelloides ایرتكب ةیضارمأ يف تادیمزلابلا رود Plesiomonas shigelloides اًیلحم ةلوزعملا

ne hundred and twenty diarrhea samples were collected from different hospitals in Baghdad, four isolates 3.3% (P1, P2, P3, P4) were obtained and identified as Plesiomonas shigelloides from these samples. Four isolates were also obtained and identified as the same bacteria from the environmental samples, two isolates 10% from twenty water samples (termed W1, W2) and two isolates 10% from twenty fish samples (termed F1, F2). Investigation of antibiotic susceptibility was done for all isolates. Some of the virulence factors were determined in this bacterium, like its ability to produce some enzymes. Ability of bacterial isolates to adhesion on epithelial cells was studied as one of important virulence factors; it was found that all isolates have the ability to adhesion on living and non-living surfaces. The plasmid profile for all isolates was studied, and the results showed that the plasmid profile was similar for all isolates. All isolates contained two small plasmid DNA bands approximately in the same sizes. The role of plasmids in pathogenicity of P. shigelloides P1 were studied, throughout cure this isolate using SDS. These results indicated that the trait of β-lactamas, haemolysin and proteinase production in addition to resistance trait for tetracycline and streptomycin were plasmids born. While the lipase and lecithinase production trait were chromosomal born in Plesiomonas shigelloides P1. صلختسملا تعمج 120 دادغب يف ةفلتخم تایفشتسم نم لاھسإ ةلاح ، 3.3 Plesiomonas shigelloides تزمر) P1 ، P2 ، P3 ، (P4 . عبرأ تصخش امك اھسفن ایرتكبلل دوعت تلازع ، 10 نم % 20 W1 ، W2 10 نم % 20 F1 ، F2 ( . میزنلأا ضعب جاتنإ ىلع اھتیلباق اھنم ایرتكبلا هذھ يف ةوارضلا ىلع ایرتكبلا هذھ تلازع ةیلباق تسرد كلذك و تا ، P.shigelloides ، طمنلا ىلع تلازعلا ھسفن يدیمزلابلا ، . اًبیرقت يئیزجلا مجحلا P.shigelloides P1 ةدام ما دخت سا ب SDS ، نع ًلاضف يمیزنأ جاتنإ ةفص امأ تادیمزلابلا ىلع ةلومحم تناك نیسیاموتبرتسلا و نیلكیاسارتتلا تاداضمل ةمواقملا ةفص ةلزعلا يف ةیموسومورك يھف نیثسللا و زیبیلالا P.shigelloides P1 . Journal of Biotechnology Research Center (Special edition) Vol.5 No.2 2011 47 Introduction Plesiomonas shigelloides, previously was belonged to the family Enterobacteriaceae, but because of morphological and biochemical differences, now belonged to the family Vibrionaceae, which include beside Plesiomonas, Vibrio and Aeromonas [1]. Plesiomonas shigelloides is aquatic microorganism, Gram negative, motile with lophotrichous flagella, non-spore-forming, facultative anaerobic, and pleomorphic microorganism. It can be isolated from human and numerous animals such as fish, birds and insects. Also from several aquatic environments (e.g. rivers, fresh water, lakes, sludge). It have been implicated as a cause of gastroenteritis infection in adults and children [2,3], also cause food poisoning and acute diarrhea beside that it cause extraintestinal infection, which include meningitis, osteomyelitis, septic arthritis, cholecystitis, peritonitis and other non diarrheal diseases.Various virulence factors have been determined in this bacterium like enterotoxin, and haemolysin also produce other enzymes which is important as virulence factors like elastase, lecithinase and proteinase [4]. It have also a higher adhesion ability to living and non living tissues, and have cytotoxin which is important for promoting colonization or invasion of epithelial cells. Other virulence factors are tetradotoxin which cause food poisoning, lipopolysaccharide (LPS) or what is called endotoxin also play an important role to the pathogenicity of this bacterium [5]. Most strains of Plesiomonas shigelloides are resistant to beta-lactam group of antibiotics, because bacteria may be produce betalactamase enzyme. Some strains are susceptible to aminoglycosides group especially to gentamicin, tobramycin [6]. It was found that this bacteria contain different molecular weight plasmids, some with small molecular weight ranging from (2-8 MDa), which are may be associated with antibiotic resistant and bacteriocin production, and the other with large molecular weight (140 MDa) which may be has been associated with adhesion of the bacteria [7]. According to those mentioned above and because of limited studies about the genetics of this Plesiomonas shigelloides, the study aimed to determine the virulence factors and attempt to determine the plasmid content and its role in pathogenecity of this