A ceiling fan is a mechanical fan, usually electrically powered, suspended from the ceiling of a room, that uses hub-mounted rotating paddles to circulate air.
Escherichia coli (E. coli) bacteria normally live in the intestines of people and animals. Most E. coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. coli are pathogenic, meaning they can cause illness, either diarrhea or illness outside of the intestinal tract.
Strains of Alcaligenes (such as A. faecalis) are found mostly in the intestinal tracts of vertebrates, decaying materials, dairy products, water, and soil; they can be isolated from human respiratory and gastrointestinal tracts and wounds in hospitalized patients with compromised immune systems.