Leptospira interrogans is a thin, P1+, motile, gram-negative, obligate aerobic spirochaete bacterium that belongs to the genus Leptospira in the phylum Spirochaetota. L. interrogans cells are long, helical, and tightly coiled like a corkscrew with hooked and spiraled ends. L. interrogans has many properties that ensure its optimal survival in specific conditions, including two periplasmic flagella located within its outer sheath, enabling the bacteria to move rapidly through a variety of mediums such as water, soil, and host tissue. These flagella enable L. interrogans to more easily access and infect mammalian tissues. The outer membrane of L. interrogans contains unique lipopolysaccharides (LPS) and surface-exposed proteins that play key roles in environmental survival, adhesion, and interaction with host organisms. It is able to metabolize long-chain fatty acids through ꞵ-oxidation as an energy source and uses oxygen as a terminal electron acceptor.