A genus of gram-positive, rod-shaped bacteria whose cells occur singly, in pairs or short chains, in V or Y configurations, or in clumps resembling letters of the Chinese alphabet. Its organisms are found in cheese and dairy products as well as on human skin and can occasionally cause soft tissue infections.
A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.