Which microorganism is known for forming endospores?

Bacillus anthracis is distinguished as a microorganism capable of forming endospores, which are highly resistant structures that allow certain bacteria to survive extreme environmental conditions, such as heat, dehydration, and exposure to chemicals. The formation of endospores is a significant survival mechanism that enables Bacillus anthracis to persist in the environment for prolonged periods, which can contribute to its pathogenicity as the causative agent of anthrax.

In contrast, Escherichia coli does not form endospores; it is a typical non-spore-forming bacterium known for its role in intestinal flora and can lead to urinary tract infections and other conditions. Streptococcus pneumoniae and Streptococcus mutans are both classified as cocci and are also non-spore-forming. They are significant in human health, with Streptococcus pneumoniae being notorious for causing pneumonia and meningitis, while Streptococcus mutans is known for its role in dental caries.

Thus, Bacillus anthracis stands out in this list for its ability to produce endospores, which is pivotal in understanding how it survives and how it can be a potential threat, particularly in bioterrorism contexts.