Pseudomonadaceae
The Pseudomonadaceae are a family of bacteria which includes the genera "Azomonas", "Azorhizophilus", "Azotobacter", "Mesophilobacter", "Pseudomonas" (the type genus), and "Rugamonas". The family Azotobacteraceae was recently reclassified into this family. History. Pseudomonad literally means false unit, being derived from the Greek "pseudo" (ψευδο – false) and "monas" (μονος – a single unit). The term "monad" was used in the early history of microbiology to denote single-celled organisms. Because of their widespread occurrence in nature, the pseudomonads were observed early in the history of microbiology. The generic name "Pseudomonas" created for these organisms was defined in rather vague terms in 1894  as a genus of Gram-negative, rod-shaped, and polar-flagellated bacteria. Soon afterwards, a large number of species was assigned to the genus. Pseudomonads were isolated from many natural niches. New methodology and the inclusion of approaches based on the studies of conservative macromolecules have reclassified many species. "Pseudomonas aeruginosa" is increasingly recognized as an emerging opportunistic pathogen of clinical relevance. Studies also suggest the emergence of antibiotic resistance in "P. aeruginosa". In 2000, the complete genome of a "Pseudomonas" species was sequenced; more recently, the genomes of other species have been sequenced, including "P. aeruginosa" PAO1 (2000), "P.  putida" KT2440 (2002), "P. fluorescens" Pf-5 (2005), "P. fluorescens" PfO-1, and "P. entomophila" L48. Several pathovars of "Pseudomonas syringae" have been sequenced, including pathovar tomato DC3000 (2003), pathovar "syringae" B728a (2005), and pathovar "phaseolica" 1448A (2005). Distinguishing characteristics. The presence of oxidase and polar flagella and inability to carry out fermentation differentiate pseudomonads from the Enterobacteriaceae.