Abstract:
The morphology of the cells of an organism formerly referred to as a member of Leptospira sp. serovar illini has been studied by electron microscopy. Cells of these strains differ morphologically from the cells of leptospires in the following:
(i) cells of the former have cytoplasmic tubules which leptospires do not possess, and (ii) the structure of the basal complex on the flagella of the former is similar to that of gram-positive bacteria, whereas the corresponding structure on the flagella of leptospires is similar to that of gram-negative bacteria. Pillot (J. Pillot, thesis, University of Paris, Paris, France, 1965) proposed in 1965 that leptospires should constitute a family, Leptospiraceae. However, Pillot proposed this name in a thesis, which is not considered to be effective publication. Hence, Leptospiraceae is here proposed as the name of a new family. In consequence of the new morphological evidence presented here together with the data from other publications on the deoxyribonucleic acid base composition and serological and cultural properties of cells of strains of Leptospira sp. serovar illini, it is proposed that this family should consist of two genera: Leptospira Noguchi 1917 and Leptonema gen. nov. The type species of Leptonema is Leptonema illini, and the type strain of this species is strain 3055 (= NCTC 11301).
* HOVIND-HOUGEN K. Leptospiraceae, a New Family to Include Leptospira Noguchi 1917 and Leptonema gen. nov. Int J Syst Evol Microbiol 29(3):245-251 doi:10.1099/00207713-29-3-245
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Conventionally, Leptospira were separated into two valid species, Leptospira interrogans for pathogenic leptospires and Leptospira biflexa for saprophytic ones (Brenner et al., 1999).
Current Leptospira speciation is based on DNA heterogeneity as determined by hybridization experiments.
The first of such studies was by Yasuda et al., 1987 followed by Ramadass et al., 1992.
The most complete study, also summarizing the observation of the previous two studies is by Brenner et al., 1999. Brenner and co-workers described 17 DNA hybridization groups (species), representing the 12 previously describes species and five new ‘genomospecies’, including Leptospira alexanderi.
Smythe et al., 2012 re-named the four remaining ‘genomospecies’ 1, 3, 4 and 5 later on to Leptospira alstonii, L. vanthielii , L. terpstrae and L. yanagawae, respectively.
To date, speciation is increasingly based on other molecular techniques, mainly DNA sequences of the rrs gene or multilocus sequence genotyping, which likely will completely replace the DNA hybridization method.
* Yasuda PH, Steigerwalt AG, Sulzer KR, Kaufmann AF, Rogers F, Brenner DJ. Deoxyribonucleic acid relatedness between serogroups and serovars in the family Leptospiroceae with proposals for seven Leptospira species. Int J Syst Bacteriol 1987, 37, 407-415
* Ramadass P, Jarvis BDW, Corner RJ, Penny D, Marshall RB. Genetic characterization of pathogenic Leptospira species by DNA hybridization. Int J Syst Bacteriol 1992, 42, 215-219
* Brenner DJ, Kaufmann AF, Sulzer KR, Steigerwalt AG, Rogers F, Weyant RS. Further determination of DNA relatedness between serogroups and serovars in the family Leptospiroceae with a proposal for Leptospira alexanderi sp. nov. and four new Leptospira genomospecies. Int J Syst Bacteriol 1999, 49, 839-858
* Smythe L, Adler B, Hartskeerl RA, Galloway RL, Turenne CY, Levett PN. Classification of Leptospira genomospecies 1, genomospecies 3, genomospecies 4 and genomospecies 5 as Leptospira alstonii sp. nov., Leptospira vanthielii sp. nov., Leptospira terpstrae sp. nov., Leptospira yanagawae sp. nov., respectively. Int J Syst Evol Microbiol 2012;
Recommended literature
* Ahmed A, Grobusch MP, Klatser P, Hartskeerl RA. Molecular Approaches in the Detection and Characterization of Leptospira. J Bacteriol Parasitol 2012, 3:2 http://dx.doi.org/10.4172/2155-9597.1000133
* Adler, B., & de la Peña Moctezuma, A. (2010). Leptospira and leptospirosis. Veterinary microbiology 140, 287-296.
* Cerqueira, G.M. & Picardeau, M. (2009). A century of Leptospira strain typing. Infection, Genetics and Evolution 9, 760-768.