Pseudomonas aeruginosa and Its Resistance

When asking healthcare professionals to name a bacterial pathogen commonly causing nosocomial infections, Pseudomonas aeruginosa always comes up in their mind.This Gram-negative nonfermenting bacterium can be found in the environment, especially in water.In healthcare settings, it is often recovered from the water supply and sinks, and can contaminate surfaces and several types of equipment, which serve as reservoirs for subsequent colonization and infection among hospitalized patients.Pseudomonas aeruginosa is also considered an opportunistic pathogen since it usually causes infections among patients with physical, phagocytic, or immunologic defects in host defense mechanisms, such as patients with major burns, neutropenia, cystic fibrosis and those receiving immunosuppressive drugs, especially corticosteroids.Antibiotic classes that are generally used to treat P. aeruginosa associated infections include anti-pseudomonal penicillins, antipseudomonal cephalosporins, anti-pseudomonal -lactam--lactamase inhibitors, group 2 carbapenems, aminoglycosides, fluoroquinolones, monobactam, phosphonic acid and polymyxins.Increasingly, there have been reports of infections due to multidrug-resistant P. aeruginosa during the past decade. 1Several of the well characterized molecular mechanisms enable P. aeruginosa to survive various hostile conditions during pathogenesis and antibiotic treatment.This bacterium can use all of the 4 main mechanisms to develop resistance to antibiotics, including producing enzymes to