The present invention pertains to a composition containing an immunogenic cell preparation of killed Leptospira bacteria in an ethylenediaminetetraacetic acid solution. The invention also pertains to a vaccine to protect an animal against an infection with leptospira bacteria, wherein the vaccine comprises this composition. Also, the invention pertains to the use of ethylenediaminetetraacetic acid to stabilize an immunogenic preparation of killed Leptospira bacteria in a liquid carrier, by dissolving the ethylenediaminetetraacetic acid in the carrier.
