Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Their ease of culture in vitro and availability of an increasing number of Pseudomonas strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include P. aeruginosa in its role as an opportunistic human pathogen, the plant pathogen P. syringae, the soil bacterium P. putida, and the plant growth-promoting P. fluorescens, P. lini, P. migulae, and P. graminis.
Pseudomonas alcaligenes is a Gram-negative aerobic bacterium used for bioremediation purposes of oil pollution, pesticide substances, and certain chemical substances, as it can degrade polycyclic aromatic hydrocarbons. It can be a human pathogen, but occurrences are very rare. Based on 16S rRNA analysis, P. alcaligenes has been placed in the P. aeruginosa group.
Pseudomonas chlororaphis is a bacterium used as a soil inoculant in agriculture and horticulture. It can act as a biocontrol agent against certain fungal plant pathogens via production of phenazine-type antibiotics. Based on 16S rRNA analysis, similar species have been placed in its group.
Pseudomonas fragi is a psychrophilic, Gram-negative bacterium that is responsible for dairy spoilage. Unlike many other members of the genus Pseudomonas, P. fragi does not produce siderophores. Optimal temperature for growth is 30 °C, however it can grow between 0 and 35 °C. Based on 16S rRNA analysis, P. fragi has been placed in the P. chlororaphis group.
Pseudomonas marginalis is a soil bacterium that can cause soft rots of plant tissues. It infects poinsettia, lettuce, and crucifers.
Pseudomonas fulva is a Gram-negative environmental bacterium, originally isolated from rice and commonly associated with rice plants, grains and paddy fields. It is rod-shaped and motile using one to three polar flagella.
Pseudomonas oleovorans is a Gram-negative, methylotrophic bacterium that is a source of rubredoxin. It was first isolated in water-oil emulsions used as lubricants and cooling agents for cutting metals. Based on 16S rRNA analysis, P. oleovorans has been placed in the P. aeruginosa group.
Pseudomonas veronii is a Gram-negative, rod-shaped, fluorescent, motile bacterium isolated from natural springs in France. It may be used for bioremediation of contaminated soils, as it has been shown to degrade a variety of simple aromatic organic compounds. Based on 16S rRNA analysis, P. veronii has been placed in the P. fluorescens group.
Pseudomonas mosselii is a Gram-negative, rod-shaped, bacterium clinically isolated in France. Based on 16S rRNA analysis, P. mosselii has been placed in the P. putida group.
Pseudomonas amygdali is a Gram-negative plant pathogenic bacterium. It is named after its ability to cause disease on almond trees. Different analyses, including 16S rRNA analysis, DNA-DNA hybridization, and MLST clearly placed P. amygdali in the P. syringae group together with the species Pseudomonas ficuserectae and Pseudomonas meliae, and 27 pathovars of Pseudomonas syringae/Pseudomonas savastanoi, constituting a single, well-defined phylogenetic group which should be considered as a single species. This phylogenetic group has not been formally named because of the lack of reliable means to differentiate it phenotipically from closely related species, and it is currently known as either genomospecies 2 or phylogroup 3. When it is formally named, the correct name for this new species should be Pseudomonas amygdali, which takes precedence over all the other names of taxa from this group, including Pseudomonas savastanoi, which is and inadequate and confusing name whose use is not recommended.
Pseudomonas taetrolens is a Gram-negative, nonsporulating, motile, rod-shaped bacterium that causes mustiness in eggs. Based on 16S rRNA analysis, P. taetrolens has been placed in the P. chlororaphis group.
Pseudomonas mucidolens is a Gram-negative, non-sporulating, motile, rod bacterium that causes mustiness in eggs. Based on 16S rRNA analysis, P. mucidolens has been placed in the P. fluorescens group.
Pseudomonas balearica is a Gram-negative, rod-shaped, nonfluorescent, motile, and denitrifying bacterium. It is an environmental bacterium that has been mostly isolated from polluted environments all over the world. Many of the isolates have demonstrated capabilities to degrade several compounds. Some of the strains are naphthalene degraders and one strain isolated in New Zealand has demonstrated the potential to oxidize inorganic sulfur compounds to tetrathionate. Based on 16S rRNA analysis, P. balearica has been placed in the P. stutzeri group.
Pseudomonas cedrina is a Gram-negative, rod-shaped bacterium isolated from spring waters in Lebanon. Based on 16S rRNA analysis, P. cedrina has been placed in the P. fluorescens group.
Pseudomonas orientalis is a Gram-negative, rod-shaped bacterium isolated from spring waters in Lebanon. Based on 16S rRNA analysis, P. orientalis has been placed in the P. fluorescens group.
Pseudomonas gessardii is a fluorescent, Gram-negative, rod-shaped bacterium isolated from natural mineral waters in France. Based on 16S rRNA analysis, P. gessardii has been placed in the P. fluorescens group.
Pseudomonas azotoformans is a Gram-negative bacterium that infects cereal grains—especially rice. Based on 16S rRNA analysis, P. azotoformans has been placed in the P. fluorescens group.
Pseudomonas stutzeri is a Gram-negative soil bacterium that is motile, has a single polar flagellum, and is classified as bacillus, or rod-shaped. While this bacterium was first isolated from human spinal fluid, it has since been found in many different environments due to its various characteristics and metabolic capabilities. P. stutzeri is an opportunistic pathogen in clinical settings, although infections are rare. Based on 16S rRNA analysis, this bacterium has been placed in the P. stutzeri group, to which it lends its name.
Kingella kingae is a species of Gram-negative facultative anaerobic β-hemolytic coccobacilli. First isolated in 1960 by Elizabeth O. King, it was not recognized as a significant cause of infection in young children until the 1990s, when culture techniques had improved enough for it to be recognized. It is best known as a cause of septic arthritis, osteomyelitis, spondylodiscitis, bacteraemia, and endocarditis, and less frequently lower respiratory tract infections and meningitis.
Streptococcus tigurinus is a novel member of the genus Streptococcus that was first discovered in 2012 by Swedish researchers.
