| Microscopic characteristic |
|
| Morphology |
Cell shape, cell size, arrangement of cells, arrangement of flagella, capsule, endospores |
| Staining reactions |
Gram stain, Acid-fast stain |
| Growth characteristics |
Appearance in liquid culture, colonial morphology, pigmentation |
| Biochemical characteristics |
Cell wall constituents, pigment biochemicals, storage inclusions, antigens, RNA molecules |
| Physiological characteristics |
Temperature range & optimum, oxygen relationships, pH tolerance range, osmotic tolerance, salt requirmnet & tolerance, antibiotic sensitivity |
| Nutritional characteristics |
Energy, carbon, nitrogen sources, fermentation products, mode of metabolism |
| Genetic characteristics |
DNA G+C%, DNA hybridization |