''Raoultella terrigena'' is a

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

l species of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Raoultella The genus ''Raoultella'' is composed of Gram-negative, Oxidase test, oxidase-negative, Aerobic organism, aerobic, motility, nonmotile, Capsule (microbiology), capsulated, Facultative anaerobic organism, facultatively anaerobic rods (formerly desi ...

'', previously classified in the genus ''

Klebsiella ''Klebsiella'' is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. ''Klebsiella'' species are found everywhere in nature. This is thought to be due to distinct sublineages developin ...

''. It has primarily been isolated from soil and water samples, but rarely from humans. Studies have estimated fewer than 1% of healthy people harbor this species. This species has rarely been shown to cause disease in humans despite expressing many of the

virulence factors Virulence factors (preferably known as pathogenicity factors or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following ...

expressed by other ''Klebsiella'' species such as ''

Klebsiella pneumoniae ''Klebsiella pneumoniae'' is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar. Although found in the normal flora of the mouth ...

''. Phylogenic comparisons between the

16s rRNA 16S rRNA may refer to: * 16S ribosomal RNA 16 S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome ( SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The g ...

and ''rpoB'' genes of this and other ''Klebsiella'' species have suggested classification into a newer genus, ''

'', a reclassification that has been adopted. ''R. terrigena'' is considered a factor in

melamine Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due t ...

toxicity. In culture, ''R. terrigena'' was shown to convert melamine to

cyanuric acid Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula (CNOH)3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleaches ...

directly. Rats colonized by ''R. terrigena'' showed greater melamine-induced kidney damage compared to those not colonized.

References

Enterobacteriaceae {{Enterobacterales-stub