Psychrobacter

Abstract Psy.chro.bac'ter. Gr. masc. adj. psychros , cold; N.L. masc. n. bacter , rod; N.L. masc. n. Psychrobacter , a rod that grows at low temperatures. Rods or cocci, 0.4–1.8 × 0.4–2.5 μm. Rods exhibit a range of lengths, from very short (coccobacilli) to relatively long forms, with some strains showing slight swelling. They may also appear as cocci or coccobacilli. Cells are not pigmented, with typical cream‐colored, smooth, and opaque colonies on heart infusion agar. Their cell wall has the Gram‐stain‐negative type, although the stain is often retained. Nonmotile and aerobic, most strains are psychrotrophilic, growing at 5°C with an optimal temperature near 20–25°C, but generally not growing above 35°C. Strains that thrive at 35–37°C usually cannot grow at 5°C. They grow well on common complex media and can thrive on mineral‐agar containing a single carbon and energy source with ammonium salts as the nitrogen source. Some strains aerobically produce acid from sugars like d ‐glucose, d ‐mannose, d ‐galactose, l ‐arabinose, d ‐xylose, and l ‐rhamnose. These bacteria are halotolerant, growing in the presence of 6.5% or higher NaCl, and many are resistant to radiation. They are oxidase and catalase‐positive, and many strains can undergo natural genetic transformation . Psychrobacter has been isolated from various environments, including the open sea, deep sea, sea ice, ornithogenic soils, fish skin and gills, poultry skin, different food products, irradiated foods, air, and human sources. However, they are not considered clinically significant. Psychrobacter cultures can be maintained similarly to Acinetobacter cultures, to which they are related. DNA G + C content (mol%) : 41.5–49.5. Type species : Psychrobacter immobilis Juni and Heym 1986 VP . Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Psychrobacter is: correct name (last update, February 2025) * . LPSN classification: Bacteria / Pseudomonadati / Pseudomonadota / Gammaproteobacteria / Pseudomonadales / Moraxellaceae / Psychrobacter The genus Psychrobacter can also be recovered in the Genome Taxonomy Database (GTDB) as g__Psychrobacter (version v220) ** . GTDB classification: d__Bacteria / p__Pseudomonadota / c__Gammaproteobacteria / o__Pseudomonadales / f__Moraxellaceae / g__Psychrobacter * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ) Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776