Further determination of DNA relatedness between serogroups and serovars in the family Leptospiraceae with a proposal for Leptospira alexanderi sp. nov. and four new Leptospira genomospecies

DNA relatedness was determined among 303 strains of Leptospira and Leptonem a. Included in the analysis were reference strains from 228 well-characteri zed and recognized serovars. The study included 268 serovars from 29 named and one or more unnamed serogroups. The strains clustered into 17 DNA hybri dization groups, representing 12 previously described species (292 strains) and five new genomospecies (11 strains). The largest groups included Lepto spira interrogans (91 strains from 82 serovars), Leptospira santarosai (65 strains from 59 serovars), Leptospira borgpetersenii (49 strains from 43 se rovars), Leptospira kirschneri (29 strains from 26 serovars) and Leptospira noguchii (20 strains from 20 serovars). The new genomospecies include Lept ospira genomospecies 1 (two strains, serovars pinagchang and sichuan), Lept ospira genomospecies 2 (six strains, serovars lushui, manhao 3, manzhuang, nanding, mengla and yunnan), Leptospira genomospecies 3 (one strain, serova r holland), Leptospira genomospecies 4 (one strain, serovar hualin) and Lep tospira genomospecies 5 (one strain, serovar saopaulo). With the exception of Ballum, all serogroups with greater than one serovar studied were geneti cally heterogeneous. Phenotypic tests, including optimal growth temperature , lipase activity and growth inhibition by copper sulfate or 2,6-diaminopur ine, were of little use in differentiating DNA relatedness groups. The name Leptospira alexanderi sp. nov. is proposed for Leptospira genomospecies 2 (type strain L 60(T) = ATCC 700520(T), serovar manhao 3).