The bacterial genus Pseudomonas includes plant pathogenic bacteria such as P. syringae (various pathovars), the opportunistic pathogen P. aeruginosa, the ubiquitous soil bacterium P. putida, and some species that are known to cause problems in dairy products. However, the actions of this group of bacteria are mainly considered neutral to man. They are considered to be metabolically diverse agents of spoilage and degradation. In recent times, members of the Pseudomonas have been used as biocontrol agents.
Members of Pseudomonas are Gram-negative, aerobic (able to consume oxygen) rods. Most are flagellated so they can move around. Most produce a slime layer that cannot be phagocytosed, and which aids in the production of surface-colonising biofilms P. fluorescens is easily recognised as it secretes large amounts of a fluorescent, yellow-green siderophores under iron-limited conditions. Many Pseudomonadaceae are capable of producing these fluorescent pigments called pyoverdines. Growth of Pseudomonads is usually accompanied by a "fruity" odor compared to Escherichia coli.
Pseudomonas are able to grow in unexpected places. They have been found in areas where a lot of pharmaceuticals are prepared. Any carbon source, such as soap residue or cap liner adhesives is a suitable place for them to thrive. Other unlikely places where they have been found include antiseptics such as ammonium compounds and bottled mineral water. Most Pseudomonas spp. are naturally resistant to penicillin and related beta-lactam antibiotics, but will succumb to piperacillin, imipenem, tobramycin, or ciprofloxacin, among others.
This ability to thrive in harsh conditions is a result of their hearty cell wall that contains porins. Their resistance to most antibiotics is attributed to their rapid efflux pumps which pump out the antibiotics before they are able to work.
The content of this page is retrieved from http://en.wikipedia.org/wiki/Pseudomonas under GFDL
