Domain Bacteria Woese et al. 1990
   Phylum Nitrospirae Garrity and Holt 2001
     Class "Nitrospira" 2001
       Order "Nitrospirales" 2001
         Family "Nitrospiraceae" 2001
           Genus Leptospirillum (ex Markosyan 1972) Hippe 2000