Molecular and phenotypic characterization of Leptospira johnsonii sp. nov., Leptospira ellinghausenii sp. nov. and Leptospira ryugenii sp. nov. isolated from soil and water in Japan

Abstract

In a previous study, 50 of 132 soil samples collected throughout Japan were found to be Leptospira‐positive. In the present study, three strains identified in the collected specimens, three, E8, E18 and YH101, were found to be divergent from previously described Leptospira species according to 16S ribosomal RNA gene sequence analysis. These three strains have a helical shape similar to that of typical Leptospira and were not re‐isolated from experimental mice inoculated with the cultured strains. Upon 16S ribosomal RNA gene sequence analysis, E8 was found to belong to the intermediate Leptospira species clade and E18 and YH101 to belong to the saprophytic Leptospira species clade. Based on analyses of genome‐to‐genome distances and average nucleotide identity in silico using whole genome sequences and DNA–DNA hybridization in vitro, these isolates were found to be distinct from previously described Leptospira species. Therefore, these three isolates represent novel species of the genus Leptospira for which the names Leptospira johnsonii sp. nov., (type strain E8 T, = JCM 32515 T = CIP111620 T), Leptospira ellinghausenii sp. nov., (type strain E18 T, = JCM 32516 T = CIP111618 T) and Leptospira ryugenii sp. nov., (type strain YH101 T, = JCM 32518 T = CIP111617 T) are proposed.

Comparison of Leptospira species isolated from environmental water and soil in Japan

“…Several studies regarding the isolation of Leptospira from environmental samples, such as soil and water, using STAFF have been reported . As a result, Leptospira were found to be ubiquitous in the environment, and more than 40 novel species isolated from soil and water collected from all over the world are proposed . In our previous study, 37.9% of soil collected from all over Japan were found to be culture‐positive when using STAFF selective medium .…”

“…Vincent et al proposed a new saprophytic clade, S2, that is branched from the saprophytic clade S1 which is composed of previously known saprophytic Leptospira species, such as L. biflexa and L. meyeri . These five isolates, as well as E30, E107, E101, E154, E156, L. ryugenii strain YH101, and L. idonii strain Eri‐1 isolated from water were found to belong to the S2 clade. Furthermore, it was revealed that some Leptospira species showed identical rrs sequences, because this leptospiral gene is highly conserved among Leptospira species .…”

“…[8][9][10] As a result, Leptospira were found to be ubiquitous in the environment, and more than 40 novel species isolated from soil and water collected from all over the world are proposed. [11][12][13] In our previous study, 37.9% of soil collected from all over Japan were found to be culture-positive when using STAFF selective medium. 14 Thus, it was found that Leptospira are commonly distributed in environmental soil in Japan.…”

Detection and modeling of anti-Leptospira IgG prevalence in cats from Lisbon area and its correlation to retroviral infections, lifestyle, clinical and hematologic changes

“…Leptospirosis is caused by an infection with spirochete bacterium of the genus Leptospira and affects humans as well as a broad spectrum of animal hosts. There are currently 27 Leptospira species as delineated by DNA–DNA hybridization ( Masuzawa et al., 2019 ). Phylogenetic analysis of these species using the 16S rRNA gene has resulted in the broad classification of the species into pathogenic, saprophytic and intermediate ( Perolat et al., 1998 ).…”

Gamification, a Successful Method to Foster Leptospirosis Knowledge among University Students: A Pilot Study

“…Leptospirosis is caused by the pathogenic species of Leptospira, primarily Leptospira interrogans . Till date, 38 species of Leptospira have been identified: 13 pathogenic, 12 intermediates, and 13 non-pathogenic (saprophytes) [5,6]. L. interrogans persistently colonizes the proximal renal tubules of carrier animals, and, once infected, the carrier animals remain symptom-free and shed infectious organisms in urine for their entire lifetime [7].…”