A bacterial spore is a structure produced by bacteria that is resistant to many environmental or induced factors that the bacteria may be subjected to. Spores help bacteria to survive by being resistant to extreme changes in the bacteria's habitat including extreme temperatures, lack of moisture/drought, or being exposed to chemicals and radiation. Bacterial spores can also survive at low nutrient levels and antibiotics and disinfectants are usually ineffective against spores. These factors make it nearly impossible to eliminate bacterial spores, as they are found in many places, especially in food products.
Most bacterial spores are not toxic and do not cause any harm, but some bacteria that produce spores can be pathogenic. Most spore-forming bacteria are contained in the bacillus and clostridium species but can be found in other species of bacteria as well. There are different types of spores including endospores, exospores, and spore-like structures called microbial cysts. Each of these aid the bacteria in survival and serve as protection for the cell.
Bacterial spores are extremely resistant. Spores of tetanus and anthrax, for example, can survive in the soil for many years. The origin of these spores was discovered in the 19th century, when a biologist noticed, under the microscope, a small, round, bright body inside bacterial cells. This survived even when the bacteria were boiled for five minutes. This killed the bacteria, but not the spores. They germinated when conditions were right. Because spores are so resistant, they are highly transmissible. This makes them a very problematic aspect of spore-forming pathogens such as Clostridium difficile.
Bacterial Spore Formation
When the bacteria is starving or senses a change in the environment, like extreme temperatures and drought, they will produce a spore. This spore is a protective, thick cell wall and can help the bacteria survive for several years by living in a dormant state. The spore is made up of few things but includes peptidoglycan, cytoplasm, water, and bacterial DNA. Once environmental conditions improve, the spore will break.