ABSTRACT
Pseudomonas spp. is aerobic, nonfermentative, Gram-negative bacteria. P. aeruginosa is the most common species associated with human disease. It is a saprophyte commonly found in soil, plants, water, and moist environments. P. aeruginosa is an opportunistic pathogen with the potential to cause infections in almost any organ system in those with physical, phagocytic, or immunologic defects in host defence mechanisms. P. aeruginosa infection can also occur in certain settings including skin infections following the use of hot tubs, whirlpools, and swimming pools. P. aeruginosa possesses a number of virulence factors, including the production of toxins and enzymes such as proteases and elastases, and phenazine pigments, such as pyocyanin. P. aeruginosa is oxidase-positive and produces two pigments, pyocyanin and pyoverdin, giving the colonies a blue-green appearance. In the outbreak setting, P. aeruginosa is usually associated with a point source, such as a faucet or contaminated equipment.
