Leptospira Interrogans - Bacteriology

LEPTOSPIRA INTERROGANS

BACTERIOLOGY

L. interrogans is the member of the genus Leptospira that is pathogenic to humans andanimals. There are other free-living species of Leptospira. This species is a slim (approxi-mately 0.15μm) spirochete 5 to 15μm long, with a single axial filament; fine, closely wound spirals; and hooked ends. It is not visualized with the usual staining procedures, and detection is best accomplished using darkfield microscopy. It can be grown in aerobic culture using certain special enriched semisolid media.

L. interrogans has multiple serogroups and over 200 serotypes, many of which werepreviously accorded species status (eg, L. icterohaemorrhagiae, L. canicola, L. pomona) based on geographic occurrence, differences in host species, and associated clinical syn-dromes. The distinction between serogroups and serotypes is of epidemiologic and epizo-ologic importance but has no clinical significance. Leptospira interrogans can survive days or weeks in some waters in the environment at a pH above 7.0. Acidic conditions, such as those that may be found in urine, rapidly kill the organism. It is highly sensitive to drying and to a wide range of disinfectants.