P. aeruginosa is the most important toxigenic pathogen within the genus Pseudomonas because of the quantity and types of invasive infections it produces, as well as the noteworthy morbidity and mortality associated. 
 This Gram-negative bacterium has the ability to survive in adverse environments and develop multiple antibiotic resistance mechanisms. Among them, the most representative are the expression of chromosomal-encoded AmpC b-lactamase, the reduction of porin channels, the production of extended-spectrum b-lactamase and the mutation of topoisomerase II and IV.
 It must be considered that several resistant mechanisms can coexist in one strain and just one of them can be effective against numerous antimicrobials