Paenibacillus

The genus Bacillus covers a large group of gram-positive to gram-variable bacilli that characteristically form endospores and generally undergo aerobic metabolism. Because B. Anthracis, a cause of serious human infection especially from spores and a potential agent in biological terrorist attacks, is a member of this genus, there has been considerable interest in the bacilli. Other members of the bacilli such as B. Cereus and B. Sublilis are also known to cause human disease that often results in sepsis. It came to be recognized that the bacilli contained a highly heterogeneous group of bacteria, a substantial number of which were gram-variable bacilli, often presenting as gram-negative, and which were facultatively anaerobic. This distinct group was referred to as "Group 3 bacilli" and included B. Polymyxa and closely related species.