Pathogenic serovars belong to L. interrogans . During the first week or so of illness, the organism can be cultured from blood and spinal fluid. After this acute phase, the organism can be cultured from the urine with a decreasing likelihood of isolation as the infection resolves. Medium-containing rabbit serum, such as Fletcher's, is satisfactory for isolation of most strains of leptospires. A few drops of blood, CSF, or urine are added to the semi-solid medium.
Organisms grow below the surface.
Leptospiras exhibit characteristic cork-screw motility. In Clinical microbiology procedures handbook . Weyant RS, et al. In Manual of clinical microbiology , 7th ed. PR Murray, et al, eds.