Pathogenicity Study of a number of Gram- negative bacilli isolated from clinical samples 1 Israa AJ. Ibrahim, 2 Rana M. Al- Shwaikh and 3 Mohammed S.Tawfeeq 49 Vol : 11 No : 4 , October 2015 ISSN: 2222-8373 Pathogenicity Study of a number of Gram- negative bacilli isolated from clinical samples 1 Israa AJ. Ibrahim, 2 Rana M. Al- Shwaikh and 3 Mohammed S.Tawfeeq 1,2 Assistant Professor of Bacteriology, Department of Biology, College of Education for pure sciences (Ibn Al-Haitham), University of Baghdad. 3 Technician, Department of Biology, College of Education for pure sciences (Ibn Al- Haitham), University of Baghdad. Received 28 January 2015 ; Accepted 24 March 2015 Abstract Fifty isolates from different clinical samples (urine and wounds) were collected from Al- Nu'man General Hospital in Baghdad city. Sampling activates were carried out from 23April to 23June 2014. The age of patient range between 40- 70 years . The Gram-negative isolates were subjected to antibiotic susceptibility, β-lactamase production (86%), biofilm formation (84%), hemolysin production (48%).The resalt appered that Escherichia coli (54%) was the most common followed by Proteus vulgaris (18%), Enterobacter aerogenes (8%), Proteus mirabilis (6%), Enterobacter cloacae (4%), Acinetobacter baumannii (4%) and (2%) for each Klebsiella oxytoca, Enterobacter gergaviae and Pseudomonas mendocina. Gram negative isolates were observed resistance (100%) for Ampicillin, Carbenicillin, Cefalothine, Cefotaxim and Meropenem. Most isolated bicteria showed less resistance to Amoxicillin / clavulanic acid and Ceftazidime, also they showed sensitivity to Imipenem. Plasmid profile analysis, Proteus vulgaris isolates showed one large plasmid only. Key words: Gram negative, Multidrug resistance, β-lactamase, biofilm, hemolysin, plasmid. Εالحان بعض اϣ ΔعزولϤ الϡ كراΔ لصبغΔلسالب اΔ العصويلبكتريا بعض اΔراضيϣ اΔراسΩ Δ السريري Ϣ ابراهيبارΠالΪ. اسراء عبΩ ˺ الشويخΪاهΠϣ . رناΩ ؛ ˻ توفيقΡ صاΪϤحϣ ؛ ˼ ˺ ؛˻ Ϣ/ قسΪساعϣ ΫاΘ اسΩاΪ بغΔعϣاΟ / ϢΜϴϬϟ اϦ ابΔفήصϟ اϡϮϠعϠϟ ΔϴبήΘϟ اΔϴϠ / كΓاϴحϟ اϡϮϠ ع ˼ ΩاΪ بغΔعϣاΟ / ϢΜϴϬϟ اϦ ابΔفήصϟ اϡϮϠعϠϟ ΔϴبήΘϟ اΔϴϠ / كΓاϴحϟ اϡϮϠ عϢ / قسϲϨ ف صΨϠϤ ال عϤΟ ϢΗ ˾5 (ΡϭήΠϟ اΕاباϬΘϟاϭ ΔϴϟϮΒϟ اϱارΠϤϟ اΕاباϬΘϟ اΖϠϤش) ΔفϠΘΨϣ Δϳήϳή سΕا حاϦϣ ΔϨϴ عϰشفΘسϣ Ϧϣ ΩاΪ بغϲ فϡعاϟ اϥاϤعϨϟ اϦϣ ΓήΘفϠϟ ˻˼ Δϳغاϟ ϥساϴϧ ˻˼ ϥاήϳΰ ح˻5˺˽ Ϧϴ بΡϭاήΘΗ ϰضήϤϟر ااϤ اعΖϧكاϭ ˽5 - 5 ؛ϪϨ س )ΕήϬث اظϴ حϡاή كΔغΒصϟ ΔΒϟساϟ ااϳήΘϜΒϟاع اϮϧ اϦϣ اϬϴϠ عϝϮحصϟ اϢΗ ϲΘϟ اΕاΰعϟع اϴϤΟ Ζϧكاϭ ˾˽ اϳήΘϜ بϰϟ اΩϮعΗ (% Escherichia coli اϬϴϠΗ باήΘϜ بProteus vulgaris ) ˺ (% ϭ Enterobacter aerogenes )  ϭ (% Proteus mirabilis ) ˿ Ϧϣ Ϟا كϬϴϠΗ (% Enterobacter cloacae اϳήΘϜبϭ Acinetobacter baumannii ΔΒسϨبϭ ) ˽ ) ΕήϬاظϭ ا ؛ϤϬϨϣ ϞϜϟ (% ˻ Ϧϣ ϞϜϟ (% Klebsiella oxytoca, ϭ Enterobacter gergaviae ϭ Pseudomonas mendocina. . ) ΖغϠبϭ ΰϴϣاΘاكاΘϴΒϟ اΕاϤϳΰϧ ااϳήΘϜΒϟ اΝاΘϧ اϦشف عϜϟ اϢΗ ˿ ΕاϤϳΰϧ اΝاΘϧاϭ ؛(% ) ΖغϠبϭ ϦϴسϳاϮϤϴϬϟ ا˽ ) ΖغϠبϭ ϱϮϴحϟء اغشاϟ اϥϮϜΗ ϰϠا عϳήΘϜΒϟ اΔϴϠقابϭ ؛(% ˽ .(%