''Phytobacter'' is a genus of
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 ...
emerging from the grouping of isolates previously assigned to various genera of the family
Enterobacteriaceae
Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject ...
. This genus was first established on the basis of
nitrogen fixing isolates from wild rice in China,
but also includes a number of isolates obtained during a 2013 multi-state sepsis outbreak in Brazil
and, retrospectively, several clinical strains isolated in the 1970s in the United States that are still available in culture collections, which originally were grouped into Brenner's Biotype XII of the ''Erwinia herbicola''-''Enterobacter agglomerans''-Complex (EEC).
Standard biochemical evaluation panels are lacking ''Phytobacter'' spp. from their database, thus often leading to misidentifications with other
Enterobacterales
Enterobacterales is an order of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria with the class Gammaproteobacteria. The type genus of this order is ''Enterobacter.''
The name Enterobacterales is derived from the ...
species, especially ''
Pantoea agglomerans
''Pantoea agglomerans'' is a Gram-negative bacterium that belongs to the family Erwiniaceae.
It was formerly called ''Enterobacter agglomerans'', or ''Erwinia herbicola'' and is a ubiquitous bacterium commonly isolated from plant surfaces, seed ...
''.
Clinical isolates of the species have been identified as an important source of extended-spectrum
β-lactamase
Beta-lactamases, (β-lactamases) are enzymes () produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems ( ertapenem), although carbapenems ...
and
carbapenem
Carbapenems are a class of very effective antibiotic agents most commonly used for the treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. ...
-resistance genes, which are usually mediated by genetic mobile elements. Strong protection of co-infecting sensitive bacteria has also been reported. Bacteria belonging to this genus are not pigmented, chemoorganotrophic and able to fix nitrogen. They are
lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix '' - ...
fermenting,
cytochrome-oxidase negative and catalase positive.
Glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
is fermented with the production of gas. Colonies growing on MacConkey agar (MAC) are circular, convex and smooth with non-entire margins and a usually elevated center. Three species are currently validly included in the genus ''Phytobacter,''
which is still included within the ''Kosakonia'' clade in the lately reviewed family of Enterobacteriaceae. The incorporation of a fourth species, ''Phytobacter massiliensis'', has recently been proposed via the unification of the genera ''Metakosakonia'' and ''Phytobacter''.
History
First described as ''Bacillus agglomerans'' in 1888 by M. W. Beijerinck and later reclassified by Ewing and Fife as ''Enterobacter agglomerans'',
the EEC has a history of many names changes and taxonomy updates that follows the evolution of taxonomy tools. In 1984, Brenner and coworkers, using DNA-DNA hybridization test, divided the EEC into thirtheen DNA relatedness groups (Biotypes), numbered from I to XIII. In 1989, Françoise Gavini and coworkers proposed to rename ''Enterobacter agglomerans'' (previously included in Biotypes I and XIII) as ''Pantoea agglomerans,''
while the genus ''Phytobacter'' emerged from the characterization of Biotype XII.
Species
*''
Phytobacter diazotrophicus
''Phytobacter'' is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from ...
'' is the most common ''Phytobacter'' species recovered from the environment and humans and is an
opportunistic pathogen
An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...
associated with contaminated
catheter
In medicine, a catheter (/ˈkæθətər/) is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Cath ...
s or the use of
total parenteral nutrition
Parenteral nutrition (PN) is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding companies. The person receives a nutritional mix ...
.
* ''
Phytobacter ursingii
''Phytobacter'' is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from ...
'' can biochemically be differentiated from ''Phytobacter diazotrophicus'' on the basis of its ability to metabolize
d-serine
Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − form ...
and
l-sorbose
Sorbose is a ketose belonging to the group of sugars known as monosaccharides. It has a sweetness that is equivalent to sucrose (table sugar). The commercial production of vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) ...
. Despite the presence of
nitrogen-fixation
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the Atmosphere of Earth, air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but al ...
genes suggests an environmental origin, only clinical isolates of the species have been reported so far.''
''
*''
Phytobacter palmae
''Phytobacter'' is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from ...
'' is a species with high nitrogen fixing ability that was first identified in Singapore in leaf tissues of oil palm (''
Elaeis guineensis
''Elaeis guineensis'' is a species of palm commonly just called oil palm but also sometimes African oil palm or macaw-fat. It is the principal source of palm oil. It is native to west and southwest Africa, specifically the area between Angola an ...
'').
*''
Phytobacter massiliensis
''Phytobacter'' is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from ...
'', whose type strain JC163
T was isolated from the fecal flora of a healthy Senegalese patient and does not possess nitrogen-fixation genes.
References
{{Taxonbar, from=Q28735297
Bacteria genera