| Morphology | Yersina |
| CELLULAR |
| Staining | Gram-negative |
| Morphology | Straight rods to coccobacilli, 0.5-0.8 um in diameter and 1-3 um in length |
| Motility | . Nonmotile at 34`C,but motile with peritrichous flagella when grown below 30`C, except for Y. pestis which is always nonmotile. |
| Specialized structures | . Endospores are not formed. Capsules are not present, but an envelope occurs in Y. pestis strains grown at 37`C or in cells from in vivo samples. |
| Division |
| COLONIAL |
| Solid surface | Growth occurs on ordinary nutrient media. Colonies on nutrient agar are translucent to opaque, 0.1-1.0 mm in diameter after 24 h |
| Liquid |
| Growth Parameters | Yersina |
| PHYSIOLOGICAL |
| Tropism | |
| Oxygen | Facultatively anaerobic, having both a respiratory and a fermentative type of metabolism. |
| pH | |
| Temperature | Optimum temperature, 28-29`C. Phenotype characteristics are often temperature- dependent, and usually more characteristics are expressed by cultures incubated at 25-29`C than at 35-37`C |
| Requirements | |
| Products | Nitrate is reduced to nitrite with a few exceptions in specific biovars. Glucose and other carbohydrates are fermented with acid production but little or no gas |
| Enzymes | Oxidase-negative. Catalase-positive |
| Unique features | The enterobacteria common antigen is expressed by all species investigated. |
| ENVIRONMENTAL |
| Habitat | Occur in a broad spectrum of habitats (live and inanimate), with some species adapted to specific hosts. |
| Lifestyle | |
| Pathogenicity |
| Distribution |
| Genome | Yersina |
| G+C Mol % | 46-50 (Tm, Bd). |
| Reference | Yersina |
| First citation | Van Loghem,J.J. (1944) The classification of plague bacillus. Antonie van Leeuwenhoek J. Serol. Microbiol 10:15-16 |
| The Prokaryotes | p |
| Bergey's Systematatic | p 498 H. Bercovier and H. H. Mollaret |
| Bergey's Determinative | p 189 |
| References |