| Morphology | Citrobacter |
| CELLULAR |
| Staining | Gram-negative. |
| Morphology | Straight rods, 1.0 um in diameter and 2.0-6.0 um in length. Occur singly and in pairs... |
| Motility | Usually motile by peri-trichous flagella. |
| Specialized structures | Usually not encapsulated |
| Division |
| COLONIAL |
| Solid surface | . Grow readily on ordinary media. Colonies on nutrient agar are generally 2-4 mm in diameter, smooth, low convex, moist, translucent or opaque and gray with a shiny surface and entire edge. Mucoid or rough forms may occur occasionally |
| Liquid |
| Growth Parameters | Citrobacter |
| PHYSIOLOGICAL |
| Tropism | Chemoorganotrophic |
| Oxygen | Facultatively anaerobic, having both a respiratory and a fermentative type of metabolism |
| pH | |
| Temperature | |
| Requirements | |
| Products | Citrate can be utilized as a sole carbon source. Nitrate is reduced to nitrite. Lysine is not decarboxylated.. Alginate and pectate are not decomposed. Glucose is fermented with the production of acid and gas. The methyl red test is postive; the Voges-Proskauer test is negative.. |
| Enzymes | Oxidase-negative. Catalase-positive Phenylalanine deaminase, gelatinase, lipase and deoxyribonuclease are not produced |
| Unique features |
| ENVIRONMENTAL |
| Habitat | Occur in the feces of man and other animals; probably normal intestinal inhabitants.. Also found in soil, water, sewage and food |
| Lifestyle | |
| Pathogenicity | Often isolated from clinical specimens as opportunistic pathogens |
| Distribution |
| Genome | Citrobacter |
| G+C Mol % | 50-52 |
| Reference | Citrobacter |
| First citation | Werkman ,C.H. and C.F.Gillan (1932) bacteria producing trimethylene glycol J. Bacteriol 23: 167-182 |
| The Prokaryotes | p |
| Bergey's Systematatic | p 458 R. Sakazaki |
| Bergey's Determinative | p 177 |
| References |