Spirillum Health Dictionary

An infectious disease following the bite of a rat. There are two causative organisms – Spirillum minus and Actinobacillus muris – and the incubation period depends upon which is involved. In the case of the former it is 5–30 days; in the case of the latter it is 2–10 days. The disease is characterised by fever, a characteristic skin rash and often muscular or joint pains. It responds well to PENICILLIN.... rat-bite fever

pl. n. (sing. bacterium) a group of microorganisms all of which lack a distinct nuclear membrane (and hence are considered more primitive than animal and plant cells) and most of which have a cell wall of unique composition (many antibiotics act by destroying the bacterial cell wall). Most bacteria are unicellular; the cells may be spherical (*coccus), rod-shaped (*bacillus), spiral (*Spirillum), comma-shaped (*Vibrio), or corkscrew-shaped (*spirochaete). Generally, they range in size between 0.5 and 5 ?m. Motile species bear one or more fine hairs (flagella) arising from their surface. Many possess an outer slimy *capsule, and some have the ability to produce an encysted or resting form (*endospore). Bacteria reproduce asexually by simple division of cells; incomplete separation of daughter cells leads to the formation of *colonies consisting of different numbers and arrangements of cells. Some colonies are filamentous in shape, resembling those of fungi. Transfer of DNA from one bacterium to another takes place in the process of *conjugation.

Bacteria are very widely distributed. Some live in soil, water, or air; others are parasites of humans, animals, and plants. Many parasitic bacteria do not harm their hosts; some cause diseases by producing poisons (see endotoxin; exotoxin).... bacteria