Which of the following genera of bacteria are known to form spores?

Bacillus and Clostridium are well-known genera of bacteria that are capable of forming endospores, a robust survival mechanism that allows them to withstand harsh environmental conditions such as extreme heat, desiccation, and chemical disinfectants. The formation of spores is a critical aspect of their life cycle, enabling them to survive in unfavorable conditions until they return to more favorable environments where they can grow and reproduce.

Bacillus species, such as Bacillus anthracis (which causes anthrax), and Clostridium species, such as Clostridium botulinum (which produces the botulinum toxin), demonstrate the capability to produce spores. These spores are resistant and can remain dormant for extended periods, only germinating when conditions are suitable.

In contrast, the other options provided contain genera that do not form spores. Staphylococcus and Streptococcus, for instance, are cocci that reproduce by binary fission and do not develop spore forms. Escherichia and Enterobacter are similarly unable to produce spores and are primarily identified by their rod shapes and rapid growth in favorable conditions. Lastly, Vibrio and Campylobacter are also non-spore-forming bacteria and are typically found in aquatic environments or as enteric pathogens