Isolation and survival of Leptospira in kidney tissue of wild rodents

By means of dark field microscopy and culture in EMJH medium, 198 kidneys from rodents of 7 murine species were tested in order to detect leptospira infection. Spirochaetal survival was also tested in a kidney tissue suspension. Thirty six (18.2%) rodents were positive; 31 of them (15.7%) were positive to leptospira by microscopic detection. Spirochaetal isolation was possible in 7 (3.5%) cases. The concordance between both tests was 82.82%. Most of the Leptospira strains survived in the renal suspension during the first 48 h. Loss of motility or its disappearance was associated to pH decrease and increase in bacterial contamination.