الفهرس 
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Abstract
The present work aims at investigating a new promising strategy for the management of resistant P. aeruginosa. This study examined the possible of redeploying different therapeutic agents including some cefepime, ceftriaxon, ceftazidime, clarithromycin, linezolid, vancomycin, and non-antibacterial drugs paracetamol and pheniramine maleate as anti-virulence factors against P. aeruginosa. Thirty five P. aeruginosa clinical isolates were isolated from various clinical sources. A total of 87% of isolates exhibited high resistant patterns, where 32% were considered to be multi drug-resistant (MDR) and 55% were extensively drug-resistant (XDR) and all isolates were found to be susceptible to colistin. Minimum inhibitory concentration of tested agents was detected, and then, the effect of sub-inhibitory concentrations of tested drugs on the bacterial growth was studied. No significant effect of the used concentrations on bacterial growth was showed. The effect of these agents at chosen concentrations on different virulence factors has been assessed. Where, cephalosporins and clarithromycin have a significant reduction on protease, hemolysin, and pyocyanin production, also they showed anti-quorum sensing activity when tested against chromobacterium violaceum Bergonzini reported strain. While the rest of tested agents did not showed inhibitory effect on virulence factors. To confirm the anti-quorum sensing activity of clarithromycin, the expression level of QS-regulated genes (lasI, lasR, rhlI, rhlR, pqsR and pqsA) was measured using RT-PCR and linezolide as a negative control was studied. As a result, clarithromycin showed a significant reduction in expression profile of tested genes, while linezolide did not.