Enterobacteriaceae is a large 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 of debate, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Pseudomonadota. In 2016, the description and members of this family were emended based on comparative genomic analyses by Adeolu et al.
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.
Enterobacter is a genus of common Gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacteria of the family Enterobacteriaceae. It is the type genus of the order Enterobacterales. Several strains of these bacteria are pathogenic and cause opportunistic infections in immunocompromised hosts and in those who are on mechanical ventilation. The urinary and respiratory tracts are the most common sites of infection. The genus Enterobacter is a member of the coliform group of bacteria. It does not belong to the fecal coliforms group of bacteria, unlike Escherichia coli, because it is incapable of growth at 44.5 °C in the presence of bile salts. Some of them show quorum sensing properties.
Paenibacillus is a genus of facultative anaerobic, endospore-forming bacteria, originally included within the genus Bacillus and then reclassified as a separate genus in 1993. Bacteria belonging to this genus have been detected in a variety of environments, such as: soil, water, rhizosphere, vegetable matter, forage and insect larvae, as well as clinical samples. The name reflects: Latin paene means almost, so the paenibacilli are literally "almost bacilli". The genus includes P. larvae, which causes American foulbrood in honeybees, P. polymyxa, which is capable of fixing nitrogen, so is used in agriculture and horticulture, the Paenibacillus sp. JDR-2 which is a rich source of chemical agents for biotechnology applications, and pattern-forming strains such as P. vortex and P. dendritiformis discovered in the early 90s, which develop complex colonies with intricate architectures as shown in the pictures:
Providencia is genus of Gram-negative, motile bacteria of the family Morganellaceae. It was named after Providence, Rhode Island, where C. A. Stuart and colleagues studied these bacteria at Brown University.
Enterobacter cloacae is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium.
Pantoea is a genus of Gram-negative bacteria of the family Erwiniaceae, recently separated from the genus Enterobacter. This genus includes at least 20 species. Pantoea bacteria are yellow pigmented, ferment lactose, are motile, and form mucoid colonies. Some species show quorum sensing ability that could drive different gene expression, hence controlling certain physiological activities. Levan produced by Pantoea agglomerans ZMR7 was reported to decrease the viability of rhabdomyosarcoma (RD) and breast cancer (MDA) cells compared with untreated cancer cells. In addition, it has high antiparasitic activity against the promastigote of Leishmania tropica.
Cronobacter sakazakii, which before 2007 was named Enterobacter sakazakii, is an opportunistic Gram-negative, rod-shaped, pathogenic bacterium that can live in very dry places, otherwise known as xerotolerance. C. sakazakii utilizes a number of genes to survive desiccation and this xerotolerance may be strain specific. The majority of C. sakazakii cases are adults but low-birth-weight preterm neonatal and older infants are at the highest risk. The pathogen is a rare cause of invasive infection in infants, with historically high case fatality rates (40–80%).
Pluralibacter gergoviae is a Gram-negative, motile, facultatively-anaerobic, rod-shaped bacterium. P. gergoviae is of special interest to the cosmetics industry, as it displays resistance to parabens, a common antimicrobial agent added to cosmetic products.
Cronobacter is a genus of Gram-negative, facultatively anaerobic, oxidase-negative, catalase-positive, rod-shaped bacteria of the family Enterobacteriaceae. Several Cronobacter species are desiccation resistant and persistent in dry products such as powdered infant formula. They are generally motile, reduce nitrate, use citrate, hydrolyze esculin and arginine, and are positive for L-ornithine decarboxylation. Acid is produced from D-glucose, D-sucrose, D-raffinose, D-melibiose, D-cellobiose, D-mannitol, D-mannose, L-rhamnose, L-arabinose, D-trehalose, galacturonate and D-maltose. Cronobacter spp. are also generally positive for acetoin production and negative for the methyl red test, indicating 2,3-butanediol rather than mixed acid fermentation. The type species of the genus Cronobacter is Cronobacter sakazakii comb. nov.
Cedecea is a genus of extremely rare bacteria of the family Enterobacteriaceae. The name of this genus was derived from CDC, the abbreviation for the Centers for Disease Control where the initial members of this genus were discovered. This genus resembles no other group of Enterobacteriaceae. Cedecea bacteria are Gram-negative, bacillus in shape, motile, nonencapsulated, and non-spore-forming. The strains of Cedecea appear to be similar to those of Serratia. Both Cedecea and Serratia are lipase positive and resistant to colistin and cephalothin; however, Cedecea is unable to hydrolyze gelatin or DNA.
Actinophytocola is a genus in the phylum Actinomycetota (Bacteria).
Dechloromonas is a genus in the phylum Pseudomonadota (Bacteria).
Enterobacter cowanii is a Gram-negative, motile, facultatively-anaerobic, rod-shaped bacterium of the genus Enterobacter. The species is typically associated with natural environments and is found in soil, water, and sewage. E. cowanii is associated with plant pathogens that exhibit symptoms of severe defoliation and plant death. This species, originally referred to as NIH Group 42, was first proposed in 2000 as a potential member of the family Enterobacteriaceae. The name of this species honors S. T. Cowan, an English bacteriologist, for his significant contributions to the field of bacterial taxonomy.
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 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 species, especially Pantoea agglomerans. Clinical isolates of the species have been identified as an important source of extended-spectrum β-lactamase and carbapenem-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 fermenting, cytochrome-oxidase negative and catalase positive. Glucose 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.
The Morganellaceae are a family of Gram-negative bacteria that include some important human pathogens formerly classified as Enterobacteriaceae. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Pseudomonadota. Genera in this family include the type genus Morganella, along with Arsenophonus, Cosenzaea, Moellerella, Photorhabdus, Proteus, Providencia and Xenorhabdus.
Intrasporangium is a genus of Gram positive, nonmotile, endospore-forming bacteria. The genus name refers to the ability to form sporangia intercalary in the mycelial hyphae. The family Intrasporangiaceae is named after the genus, and Intrasporangium is the type genus for the family.
Intrasporangium oryzae is a species of Gram positive, strictly aerobic bacterium. The species was initially isolated from rice paddy soil. The species was first described in 2007, and its name is derived from Latin oryzae. It was originally placed in the novel genus Humihabitans, but further research reclassified the species as a member of the existing genus, Intrasporangium. Because Humihabitans was monospecific, with H. oryzae as the only species, the genus is now defunct.
Pluralibacter is a genus of Gram negative bacteria from the family of Enterobacteriaceae. The genus consists of two species, P. gergoviae and P. pyrinus. Both species were originally classified in the genus Enterobacter, but were reclassified into the novel genus Pluralibacter in 2013.
Pluralibacter pyrinus is a Gram-negative, motile, facultatively-anaerobic, rod-shaped bacterium. P. pyrinus is the causitive agent of brown leaf spot disease of pear trees.
