Aeromonas

Abstract

Ae.ro.mo' nas. Gr. n.aerair, gas; Gr. n.monasunit, monad; M.L. fem. n.Aeromonasgas(‐producing) monad.Proteobacteria / Gammaproteobacteria / Aeromonadales / Aeromonadaceae / AeromonasCells straight, coccobacillary to bacillary with rounded ends, 0.3–1.0 × 1.0–3.5 µm. Occur singly, in pairs, or rarely in short chains. Gram negative.Most species are motile by a single, polar flagellumof 1.7 µm wavelength; peritrichous flagella may be formed on solid media in young cultures and lateral flagella occur in some species. Facultatively anaerobic. Chemoorganotrophic, displaying oxidative and fermentative metabolism ofD‐glucose. Acid and often acid with gas produced from many carbohydrates, especiallyD‐glucose. Nitrate is reduced to nitrite. A variety of exoenzymes such as arylamidases, amylase, DNase, esterases, peptidases, and other hydrolytic enzymes are produced. Main cellular fatty acids are hexadecanoic acid (C16:0), hexadecenoic acid (C16:1), and octadecenoic acid (C18:1).Usually oxidase positive and catalase positive. Optimum growth temperature varies between 22°C and 37°C; growth temperature can range from 0 to 45°C, and some species do not grow at 35°C.Generally resistant to 150 μg of the vibriostatic agent 2,4 diamino‐6, 7‐diisopropylpteridine (0/129). Occur in fresh, brackish, tap, well, and chlorinated water, as well as biosolids and sewage. Some of the species have been associated with disease in a wide variety of warm‐blooded and cold‐blooded animals, including humans, domestic animals, frogs, fresh and salt water fish, and invertebrates. The phylogenetic position ofAeromonas, as determined by 16S rRNA gene sequence analysis, is in theGammaproteobacteria, with its closest relatives in the familiesVibrionaceaeandEnterobacteriaceae. 16S rDNA sequences (signature sequences) have been determined for nearly all validly named species and are deposited in GenBank, EMBL, or RDP databases (Table BXII.γ180).The mol%G+C of the DNA is: 57–63.Type species:Aeromonas hydrophila(Chester 1901) Stanier 1943, 213 (Bacillus hydrophilusChester 1901 , 235.)