====== Bacterium ======


(Plural: Bacteria singular: bacterium) constitute a large domain of prokaryotic [[microorganism]]s. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. They are also known to have flourished in manned spacecraft.

see [[Gram negative Bacteria]]

see [[Gram-positive bacteria]]

see [[Bacterial infection]]

[[Antibiotic resistant bacteria]]