Genetic Characterization of Pathogenic Leptospira Species by DNA Hybridization

Abstract

A total of 66 serovars of potentially pathogenic Leptospira species were examined by slot blot hybridization, and 57 of these serovars were classified in six DNA homology groups. In cases in which common serovars were studied, the results were in general agreement with the results of previous workers, who used different DNA homology methods. However, we propose a new species, Leptospira kirschneri, comprising the following serovars: bulgarica, butembo, cynopteri, dania, grippotyphosa, kabura, kambale, ramisi, and tsaratsovo. Seven of these serovars have not had their DNAs studied by other workers.Differentiation of strains within Leptospira species based upon variations in antigenic composition was introduced nearly 40 years ago. A total of 223 Leptospira serovars have been identified, and for convenience these serovars are grouped into 23 serogroups (10). Haapala et al. in 1969 (5) and Brendle et al. in 1974 (1) reported DNA base compositions of and measured levels of DNA homology between selected leptospire strains. The methods which these authors used had the potential to indicate the genetic structure of the genus Leptospira and to provide information that could be used to produce a phylogenetic classification. The results of a comprehensive study of 45 serovars in which quantitative DNA-DNA hybridization experiments were performed were published in 1987 (17). A total of 40 pathogenic strains were placed in five homology groups and were described as new species of the genus Leptospira. Leptospira interrogans was restricted to serovars icterohaemorrhagiae, copenhageni, canicola, pomona, saxkoebing, wolffi, pyrogenes, autumnalis, bataviae, jalna, australis, smithi, schueffneri, zanoni, grippotyphosa, djasiman, and hebdomadis; Leptospira noguchi comprised serovars panama, fortbragg, and louisiana; Leptospira weilii comprised serovars celledoni and sarmin; Leptospira santarosai comprised serovars shermani, borincana, peru, hawaiin, bananal, atlantae, bakeri, and navet; Leptospira borgpetersenii comprised serovars javanica, ballum, mini, tarassovi, and sejroe; and Leptospira inadai comprised serovar lyme. Yasuda et al. (17) determined levels of relatedness at 55 and 70°C by using the hydroxyapatite method (2). In this study we found that it was impractical to obtain the quantities of leptospire DNA that are required by this method for an extensive survey and instead used slot blot hybridization at 60°C. We found that the results obtained with slot blot hybridization were accurate and reproducible. Our results are in good agreement with those of Yasuda et al. (17).In this paper we describe the use of a quantitative slot blot hybridization method to determine the levels of DNA relatedness of 66 pathogenic leptospire serovars; to do this, we used 16 strains as sources of labeled reference DNA. * Corresponding author. MATERIALS AND METHODSLeptospira serovars and culture conditions. Cultures of Leptospira strains were obtained either from the WHO/FAO Collaborating Leptospirosis Laboratory, Brisbane, Australia, or fro...

Exilispira thermophila gen. nov., sp. nov., an anaerobic, thermophilic spirochaete isolated from a deep-sea hydrothermal vent chimney

“…Differential characteristics between strain RASEN T and other genera in the phylum Spirochaetes Data for strain RASEN T are from this study. Data for other genera were taken from Holt et al (1994), Paster et al (1991) and the following sources: Treponema (Norris et al, 2006;Smibert, 1984;Wyss et al, 2004;Nordhoff et al, 2005;, Spirochaeta (Leschine et al, 2006;Canale-Parola, 1984a, b;Hoover et al, 2003;Dröge et al, 2006), Borrelia (Caimono, 2006;Kelly, 1984;Güner et al, 2004;Masuzawa et al, 2001;Fukunaga et al, 1996;Richter et al, 2004;Le Fleche et al, 1997;Baranton et al, 1992;Canica et al, 1993;Wang et al, 1997;Karimi et al, 1979), Cristispira (Breznak, 1984), Brevinema (Defosse et al, 1995), Brachyspira (Stanton, 2006;Hampson & La, 2006) and Leptospira/Leptonema (Adler & Faine, 2006;Faine, 1984;Levett et al, 2006;Perolat et al, 1998;Ramadass et al, 1992). +, Positive; 2, negative; V, dependent on the species; ND, no data available.…”

Differentiation of Leptospira species and serovars by PCR-restriction endonuclease analysis, arbitrarily primed PCR and low-stringency PCR

“…Non-pathogenic serovars were similarly classified into a single species, L. bzjiexa. However, the phenotypic classification has been replaced by a genomic one in which 11 species are defined, based upon DNA relatedness [3,4]. Pathogenic serovars are found within eight of these genomic species of Leptospira.…”

Les leptospiroses : actualités cliniques

“…Les animaux domestiques et sauvages ser vent de réservoirs potentiels de l'infection humaine et de celles d'autres ani maux hôtes. Le genre a été divisé en deux nouvelles espèces sur la base des nouvelles données génétiques (L. interrogans sensu stricto et L. kirschneri) [14]. La plus grande fréquence des pics de la maladie se situe pendant les périodes humides et tempérées.…”