scanning electron micrograph (SEM) of a number of Pseudomonas aeruginosa bacteria.( Janice Haney Carr 2008, Wikimedia commons)

The Pseudomonas species are Gram-negative rods. They are obligate aerobes and are oxidase and catalase positive.

The Pseudomonas species are motile by polar flagellae and cause opportunistic infections. Most Pseudomonas species are resistant to antibiotics due to their efflux pumps, which pump out the antibiotics before they can act. They contain porins in their cell wall that allows them to survive harsh conditions.

References

Krieg, Noel (1984). Bergey's Manual of Systematic Bacteriology, Volume 1. Baltimore: Williams & Wilkins.