Leptospira interrogans

Leptospira interrogans is a thin, P1+, motile, gram-negative, obligate aerobic spirochaete bacteria 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.

L. interrogans is mainly found in warmer tropical regions. The bacteria can live for weeks to months in the ground or water. Leptospira is one of the genera of the spirochaete phylum that causes severe mammalian infections. Although many Leptospira species can cause infection, most of the serious infections are caused by L. interrogans. This species is pathogenic to some wild and domestic animals, including pet dogs. It can also spread to humans through abrasions on the skin with contaminated water or soil, where infection can cause flu-like symptoms with kidney and liver damage.

L. interrogans has a genome that consists of two circular chromosomes. Together, these chromosomes encode genes involved in motility, nutrient acquisition, stress response, and adaptation to different ecological niches.