Microbe is a term for tiny creatures that individually are too small to be seen with the unaided eye. Microbes include bacteria, fungi, protists, and viruses. Bacteria are single-celled microbes that reproduce by splitting in two. There are more than 5,000 known species of bacteria, with new ones constantly being discovered. Familiar species include E. coli, Salmonella, Bacillus, and Streptococci.
Bacteria prefer moist conditions and can live in a wide range of temperatures. Some bacteria form spores which are resistant to drying and heating. When conditions become favourable again, they germinate and an active cell is released.
Bacteria cells have four basic shapes: spheres, spirals, rods, and commas. They can be found as single cells, in pairs, chains, or clusters. A bacterial cell has a wall which maintains its shape and protects it. Some bacteria can move, usually using flagella, which are like little corkscrews that rotate from the base like a ship's propeller. Some bacteria have numerous fringe-like projections called fimbriae which enable them to stick to each other. Other bacteria produce a sticky substance around the cell wall, which provide protection and helps them stick to substrates, as well as each other.
Studies have been preformed to document where the highest concentration of bacteria in a household are located. The object with the highest count of bacteria in a household appeared to be the kitchen cleaning material (sponge, dishcloth, or dish mop). The toilet seat ranked only 14th. Anytime you use a cleaning material, such as a sponge, to wipe a surface, you are potentially spreading bacteria. When allowed to multiply on food, the bacteria can cause illness through food poisoning. Handling the sponge can also cause infection through an open wound. Examples of bacteria found on kitchen cleaning materials include Salmonella, E. coli, Bacillus, Listeria, Staphylococci, and Streptococci.