A single strain (designated Khorat-H2) was isolated from the urine of an adult male patient with suspected leptospirosis from the province of Nakornrachasima, Thailand. The isolate showed typical motility and morphology under dark-field microscopy. Cells were 10–13 μm long and 0.2 μm in diameter, with a wavelength of 0.5 μm and an amplitude of approximately 0.3 μm. Phenotypically, strain Khorat-H2 did not grow at 13 °C but grew at 30 and 37 °C and in the presence of 8-azaguanine. Serological identification using the microscopic agglutination test revealed that strain Khorat-H2 had no cross-reaction with any recognized serogroups. Phylogenetic analysis of the 16S rRNA gene sequence placed the novel strain within the radiation of the genus , with sequence similarities of 88.1–97.7 % to recognized species. DNA–DNA hybridization against the type strains of the three most closely related species was used to confirm the results of the 16S rRNA sequence analysis. The G+C content of strain Khorat-H2 was 41.8 mol%. On the basis of phenotypic, serological and phylogenetic data, strain Khorat-H2 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain is Khorat-H2 (=WHO LT1686 =KIT Khorat-H2).


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