Spirilla

Spirilla

Collected together under this heading are several genera of aerobic (mostly mi-croaerophilic) spiral-shaped bacteria with polar flagella. These include free-living, sym-biotic and parasitic types.

Spirilla such as Aquaspirillum and Magnetospirillum contain magnetosomes, intra-cellular particles of iron oxide (magnetite, Fe3O4). Such magnetotactic bacteria have the remarkable ability to orientate themselves with respect to the earth’s magnetic field (magnetotaxis).

Two important pathogens of humans are included in the spirilla; Campylobacterjejuni is responsible for foodborne gastroenteritis, while Helicobacter pylori has in recenttimes been identified as the cause of many cases of peptic ulcers.

Representative genera: Magnetospirillum, Campylobacter