procaryotes
   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