الفهرس 
Introduction and Aim of WorkOnly 14 pages are availabe for public view
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Abstract
P. aeruginosa is an opportunistic nosocomial pathogen that is able to cause severe invasive diseases in immunocompromised patients such as malignant external otitis, endophthalmitis, endocarditis, meningitis, septicemia, urinary-tract infections in catheterized patients, hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. It represents a challenge for antimicrobial chemotherapy due to its intrinsic low permeability to various antimicrobial agents and its potential to develop antibiotic resistance via several mechanisms which may leads to therapy failure. This study was conducted to evaluate the activity of different cephalosporins against P. aeruginosa in different clinical specimens obtained from patients attending Al-Helal hospital and to determine the possible mechanisms of resistance using phenotypic and genotypic methods.
In this study, 255 clinical samples from patients attending Al-Helal hospital with different kinds of infections [28 burn, 157 wound, 50 respiratory tract and 20 urinary tract infections] were tested for P. aeruginosa. Out of 255 clinical samples, 48 (18.8%) were positive for P. aeruginosa.
P. aeruginosa was highly prevalent in burns (20/28; 71.4%) followed by urinary tract infection (4/20; 20%) followed by skin infections (21/157; 13.4%) followed by respiratory tract infection (3/50; 6%).
The 48 P. aeruginosa isolates were screened for their susceptibility to different Cephalosporins. All isolates were completely resistant (100%) to all the tested cephalosporin antibiotic except for cefoperazone/sulbactam and cefoperazone. Cefoperazone/sulbactam showed the least resistance (29.2%) against P. aeruginosa followed by cefoperazone (33.3%).
All P. aeruginosa isolates were subjected to β-lactamase detection. Our results showed that 33 (68.8%) of P. aeruginosa isolates produced β-lactamases.
Quantitative biofilm determination using the microtiter assay revealed that 46 (95.8%) isolates were biofilm producers. Using PCR technique for determination of different genes responsible for antibiotic resistance, out of the 48 isolates, 22 (45.8%), 6 (12.5%), 6 (12.5%), 4 (8.3%), and 10 (20.8%), amplified the blaTEM, blaCTX, CMY-2, icaA, icaD genes, respectively.