Pseudomonas bacteria are any bacteria of the Pseudomonas genus of gamma proteobacteria. This type of bacteria is often infectious and has many characteristics in common with other pathogenic bacteria. They occur very commonly in water and some types of plant seeds, and for this reason, were observed very early on in the history of microbiology. The name Pseudomonas literally means “false unit.”
Pseudomonas bacteria are rod-shaped like many other bacterial strains, and are Gram-negative. This means that when stained with a certain violet-red dye according to the Gram staining protocol, they do not retain the dye’s color after being washed. This fact gives important clues about the structure of the cell wall of these bacteria. It shows that it is resistant to certain types of antibiotics, which fact is proving to be increasingly relevant.
One type of Pseudomonas bacteria is the Pseudomonas aeruginosa, which is responsible for an increasing number of infections in hospital patients, particularly those suffering from cancer or severe burns. This opportunistic pathogen has very minimal nutritional requirements, evidenced by the fact that it has been found growing in distilled water. Its preferred temperature for growth is 98.6 degrees Fahrenheit (37 degrees C), making it especially suited for infecting the tissues of the human body. It is important to note, though, that this bacterium is often found harmlessly on the skin and in the bodies of healthy persons.
Some kinds of Pseudomonas bacteria are also pathogenic to plant life. Many of these, interestingly enough, show a tendency to only infect certain plants in certain ways, and to use specific tactics in doing so. Even when not strictly a plant pathogen, these bacteria can affect agriculture in other ways, often causing problems in the cultivation of mushrooms.
Because of the infectious nature of these bacteria, they can actually be used to combat other agricultural pathogens. Since the 1980s, certain types of Pseudomonas bacteria, such as Pseudomonas fluorescens, have been applied directly to soils and seeds in order to prevent the growth of crop pathogens. This practice of deterring one type of pathogen with another is generally referred to as biocontrol. Another member of the Pseudomonas genus which has biocontrol properties is Pseudomonas chlororaphis, which itself produces an antibiotic which is active against certain fungi that attack plants. There is still much study to be done in the area of biocontrol, and Pseudomonas bacteria may yet prove to have additional helpful qualities.