الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Pseudomonas aeruginosa is a leading cause of nosocomial infections, including pneumonia, urinary tract infections, and bacteremia. The infections can be particularly severe in patients with impaired immune systems, such neutropenic or cancer patients. Pseudomonas aeruginosa is intrinsically resistant to a wide range of drugs and pursue an extraordinary resistant mechanism against other antimicrobials.
This study was carried out to detect the incidence of Pseudomonas aeruginosa species, in some hospitalized patients, study of the antibiogram of the isolated strains against different antimicrobial agents and possible mechanisms of resistance of the isolated pseudomonas aeruginosa to them, Detection of Amp C β-lactamases by Iodometric method, Detection of extended spectrum β-lactamases (ESBLs) by double-disc synergy test, detect inducible third-generation cephalosporin resistance in enterobacteriaceae and isolation and analysis of plasmid DNA product.
In the present study, a total of 58 P. aeruginosa isolates were obtained from 330 samples collected from different infections, P. aeruginosa was mostly isolated from burn unit followed by urinary tract infections .they are collected from Minia university, Minia General and Minia chest hospitals. Out of 330 clinical specimens, 50 were urine specimens, 150 were sputum specimens, 50 were post operative wound exudates specimens, 50 were abscess discharges specimens and 30 were burn swabs specimens.
P. aeruginosa represented 58 clinical samples or 17.6 % of total clinical samples. Out of these 58 P. aeruginosa isolates, 22 were burn swabs isolates, 11 were urine isolates, 10 were sputum isolates ,10 were abscess discharge isolates and 5 were post operative wound exudates isolates ,
Antibiotic resistance pattern revealed that all Pseudomonas aeruginosa showed resistance to most of the tested antimicrobials. All isolates were completely resistant to amoxicillin and showed high resistance to the tested β-lactams and cephalosporins. Low resistance was shown against amikacin (25.8%), it is clear that in general, clinical P.aeruginosa isolates were absolutely resistant to ampicillin and amoxicillin, Out of 330 isolates 54 isolates (93%) were resistant to ampicillin, 53 isolates(91%) were resistant to ampicillin/ sulbactam ,and 58 isolates (100%) were resistant to amoxicillin, and 51 isolates (88%) were resistant to amoxicillin/clavulonic acid, and 37 isoaltes (64%) were resistant to gentamycin, and 52 isolates (89%) were resistant to cefotaxime, and 31 isolates (53%) were resistant to cefipime, and 15 isolates ( 25.8%) were resistant to amikacin, and 34 isolates (58.6%) were resistant to ciprofloxacin, and 43 isolates ( 74%) were resistant to levofloxacin, Minimum inhibitory concentration was performed.
In this study all strains of P. aeruginosa isolates were resistant to ampicillin, all strains were subjected to β-lactamase detection. Out of 58 clinical Pseudomonas aeruginosa isolates, 42 strains were β-lactamase producers constituting 72% of the total tested clinical strains.
They were also tested for ESBLs production by DDST. ESBLs production was found in 27.5% of P. aeruginosa isolates. Inducible ESBLs production testing revealed that there is no inducible ESBLs production among the tested strains.
It was found that 75.8% of P. aeruginosa isolates were multi-drug resistant. Most of multi-drug resistant isolates were obtained from wound infections as all wound samples were multidrug resistant followed by burns (90.9% of burn samples). ESBLs production was mostly observed among strains isolated from burn units.
Antibiotic resistance pattern of ESBLs producers revealed that all tested ESBLs producing isolates were completely resistant to all tested antibiotics except gentamicin (68.7%), azetreonam and amikacin (62.5% each).
β-lactamase producing strains were screened for their plasmid profile and it was found that some β-lactamase producing strains contain plasmids and others do not. It was found that out of 16 ESBLs producers, 9 strains harbored plasmid. The Antibiogram of these 9 strains revealed that 3 of them were resistant to all antibiotics except Amikacin (2 strains from wound and one strain isolated from burn) while the other 6 strains were completely resistant to all tested antibiotics
Conclusion
•P. aeruginosa was mostly isolated from burn units, followed by urinary tract infections.
•Antibiotic resistance pattern revealed that all Pseudomonas aeruginosa showed resistance to most of the tested antimicrobials, early identification of the infections due to these organisms is necessary as the appropriate treatment might reduce the spread of these resistant strains as well as reduce the mortality in hospitalized patients.
•ESBLs producing organisms are completely resistant to all tested antimicrobials but low activity was shown by aztreonem, amikacin and gentamycin. This suggests a possible existence of co-resistance to quinolones and aminoglycosides on the gene responsible for ESBLs production.
the high prevalence of multidrug resistant Pseudomonas aeruginosa producing β-lactamase enzymes of diverse mechanisms. To combat these problems, epidemiological studies should be undertaken in hospital settings to monitor the source of infection.
Early detection of these β-lactamase producing isolates in a routine laboratory could help to avoid treatment failure.
• Strict antibiotic policies and measures to limit the indiscriminative use of cephalosporins and carbapenems in the hospital environment should be undertaken to minimize the emergence of this multiple β-lactamase producing pathogen whose spread would leave no other option to treat gram-negative nosocomial infections.