Cronobacter is a genus of Gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, facultatively-anaerobic

Facultative anaerobic organism

A facultative anaerobic organism is an organism, usually a bacterium, that makes ATP by aerobic respiration if oxygen is present but is also capable of switching to fermentation...

, oxidase

Oxidase

An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide ....

 negative, catalase

Catalase

Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...

 positive, rod-shaped

Bacillus

Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...

 bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 of the family Enterobacteriaceae

Enterobacteriaceae

The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...

.
They are generally motile, reduce nitrate

Nitrate

The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...

, utilize citrate

Citrate

A citrate can refer either to the conjugate base of citric acid, , or to the esters of citric acid. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate.-Other citric acid ions:...

, hydrolyze esculin and arginine

Arginine

Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...

, and are positive for L-ornithine

Ornithine

Ornithine is an amino acid that plays a role in the urea cycle.-Role in urea cycle:L-Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen....

 decarboxylation

Decarboxylation

Decarboxylation is a chemical reaction that releases carbon dioxide . Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carbonation, the addition of CO2 to...

. Acid is produced from D-glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

, D-sucrose

Sucrose

Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...

, D-raffinose

Raffinose

Raffinose is a trisaccharide composed of galactose, fructose, and glucose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains. Raffinose can be hydrolyzed to D-galactose and sucrose by the enzyme α-galactosidase , an enzyme not found in the...

, D-melibiose

Melibiose

Melibiose is a reducing disaccharide formed by an alpha-1,6 linkage between galactose and glucose . It can be formed by invertase mediated hydrolysis of raffinose, which produces melibiose and fructose. Melibiose can be broken down into its component saccharides, glucose and galactose, by the...

, D-cellobiose

Cellobiose

Cellobiose is a disaccharide with the formula [HOCH2CHO3]2O. Cellobiose consists of two glucose molecules linked by a β bond. It can be hydrolyzed to glucose enzymatically or with acid. Cellobiose has eight free alcohol groups, one acetal linkage and one hemiacetal linkages, which give rise to...

, D-mannitol

Mannitol

Mannitol is a white, crystalline organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator...

, D-mannose

Mannose

Mannose is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. It is not part of human metabolism, but is a component of microbial cell walls, and is therefore a target of the immune system and also of antibiotics....

, L-rhamnose

Rhamnose

Rhamnose is a naturally occurring deoxy sugar. It can be classified as either a methyl-pentose or a 6-deoxy-hexose. Rhamnose occurs in nature in its L-form as L-rhamnose . This is unusual, since most of the naturally occurring sugars are in D-form...

, L-arabinose

Arabinose

Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde functional group.For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.For sugars, the D/L...

, D-trehalose

Trehalose

Trehalose, also known as mycose or tremalose, is a natural alpha-linked disaccharide formed by an α,α-1,1-glucoside bond between two α-glucose units. In 1832, H.A.L. Wiggers discovered trehalose in an ergot of rye, and in 1859 Marcellin Berthelot isolated it from trehala manna, a substance made...

, galacturonate and D-maltose

Maltose

Maltose , or malt sugar, is a disaccharide formed from two units of glucose joined with an αbond, formed from a condensation reaction. The isomer "isomaltose" has two glucose molecules linked through an α bond. Maltose is the second member of an important biochemical series of glucose chains....

.
Cronobacter are also generally positive for acetoin production (Voges–Proskauer test) and negative for the methyl red

Methyl red

Methyl red, also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder....

 test indicating 2,3-butanediol

2,3-Butanediol

2,3-Butanediol is a chemical compound composed of carbon, hydrogen, and oxygen. Its formula is C4H10O2. It is one of the constitutional isomers of butanediol....

 rather than mixed acid fermentation

Mixed acid fermentation

Mixed acid fermentation is an anaerobic fermentation where the products are a complex mixture of acids, particularly lactate, acetate, succinate and formate as well as ethanol and equal amounts of H2 and CO2. It is characteristic for members of the Enterobacteriaceae family.-External links:*...

.
The type species of the genus Cronobacter is Cronobacter sakazakii comb. nov.

Clinical significance

Cronobacter are recognised as causative agents of neonatal bacteraemia, meningitis

Meningitis

Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

 and necrotising enterocolitis. Although rare, some cases have been linked to the consumption of contaminated reconstituted infant formula

Infant formula

Infant formula is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, usually prepared for bottle-feeding or cup-feeding from powder or liquid . The U.S...

.

Taxonomy

Cronobacter was first proposed as a new genus in 2007 as a clarification of the taxonomic relationship of the biogroups found among strains of Enterobacter sakazakii

Enterobacter sakazakii

Enterobacter sakazakii is a Gram-negative rod-shaped pathogenic bacterium. It is a rare cause of invasive infection with historically high case fatality rates in infants.It can cause bacteraemia, meningitis and necrotising enterocolitis. E...

. This proposal was validly published in 2008 with 5 species and 3 subspecies named .

Etymology

Cronobacter (Cro.no.bac'ter. Gr. n. Cronos (Κρόνος), one of the Titans

Titan (mythology)

In Greek mythology, the Titans were a race of powerful deities, descendants of Gaia and Uranus, that ruled during the legendary Golden Age....

 of mythology who swallowed each of his children as soon as they were born; N.L. masc. n. bacter

-bacter

-Meaning:Bacter is a Neolatin term coined from bacterium, which in turn derives from the Greek βακτήριον, meaning small staff...

, a rod; N.L. masc. n. Cronobacter, a rod that can cause illness in neonates).

Cronobacter sakazakii (sak.a.zaki.ī. N.L. gen. n. sakazakii, of Sakazaki) is named in honour of the Japanese microbiologist Riichi Sakazaki .

Cronobacter malonaticus (mă.lō.nă.tĭ'cŭs. N.L. n. malonas -atis, malonate; L. suff. -icus, suffix used with the sense of belonging to; N.L. masc. adj. malonaticus, pertaining to the utilisation of malonate

Malonate

The malonate or propanedioate ion is CH222− . Malonate compounds include salts and esters of malonic acid, such as*diethyl malonate, 2,*dimethyl malonate, 2,...

). The type strain, CDC 1058-77T, was isolated from a breast abscess .

Cronobacter turicensis (tŭ.rĭ.sĕn'sĭs. L. masc. adj. turicensis, pertaining to Turicum

Turicum

Turicum was a Swiss automobile manufactured between 1904 and 1906 in Zurich, 1907 till 1912 in Uster. Turicum is the Latin name of Zurich....

, the Latin name of Zurich

Zürich

Zurich is the largest city in Switzerland and the capital of the canton of Zurich. It is located in central Switzerland at the northwestern tip of Lake Zurich...

, Switzerland) .

Cronobacter muytjensii (mœ.tjәn.sĭ.ī. N.L. gen. n. muytjensii, of Muytjens) is named in honour of the Dutch microbiologist Harry Muytjens who performed much of the early work on Enterobacter sakazakii .

Cronobacter dublinensis (dŭb.lĭn.ĕn'sĭs. N.L. masc. adj. dublinensis, pertaining to Dublin, Ireland, the origin of the type strain) .

C. dublinensis subsp. lausannensis (lô.săn.ĕn'sĭs. L. masc. adj. lausannensis, pertaining to Lausanne

Lausanne

Lausanne is a city in Romandy, the French-speaking part of Switzerland, and is the capital of the canton of Vaud. The seat of the district of Lausanne, the city is situated on the shores of Lake Geneva . It faces the French town of Évian-les-Bains, with the Jura mountains to its north-west...

, Switzerland, the origin of the type strain for this subspecies) .

C. dublinensis subsp. lactaridi (lăkt.ărĭd.ī. L. n. lac lactis, milk; L. adj. aridus, dried; N.L. gen. n. lactaridi, of a dried milk) .