Objective To establish the method of multiple loci VNTR(variable numbers tandem-repeats) analysis (MLVA) for genotyping Leptospira interrogans serogroup ieterohaemorrhagiae . Methods Seven VNTR loci were chosen for genotyping 117 strains of L. interrogans serogroup Icterohaemorrhagiae by PCR-electrophoresis-based VNTR analysis and the results were analyzed by software BioNumerics( Version 4.0). Results One hundred and seventeen isolates of L. interrogans serogroup Icterohaemorrhagiae detec-ted with 7 VNTR loci were classified into three clusters(A,B,C), twenty-eight types were found, type A 11.97% (14/117), type B 0.85% (1/1 17), type C 87.18% (102/117). Diversity Indexes for the loci varied between 0.0831 and 0.8005. Clinical strains isolated from the same geographic area and belonging to the same serogroup shared a common VNTR pattern. Conclusion MLVA could be used to classify and identify Leptospira interrogans preliminarily. With the improvement of technology, this rapid and easy method should greatly contribute to a better knowledge of the epidemiology of Leptospira.

Objective:To understand the etiological characteristics of the patients with fever of unknown origin in Guizhou province through the isolation and identification of Leptospira interrogans and provide evidence for the control, prevention and treatment of human leptospirosis. Methods:Blood and urine samples were collected from patients with fever symptoms in Qiandongnan, an epidemic area, in Guizhou. The suspected Leptospira strains were primarily identified using pathogenic Leptospira specific G1/G2-PCR, and subsequently identified by using Leptospira serogroups specific PCR. The Leptospira strains were then genotyped with multiple locus sequence typing. MLST data based cluster analysis on the isolates and Leptospira reference strains of common serogroups were analyzed by using software NTsys 2.10e. Results:Three suspected strains of Leptospira were isolated from human blood samples, the isolation rate was 8.６%, which were designated as strain 17BX002, 17BX003 and 17AJX008. Strain 17BX002 was further identified as serogroup grippotyphosa by using Leptospira serogroup specific PCR, while the other two strains were negative (excluded as iterohaemorrhagiae, sejroe, canicola, autumnalis, grippotyphosa and hebdomadis). MLST genotyping showed that strain 17BX002 was typed as ST106, most closely clustered with Leptospira grippotyphosa, while strain 17BX003 and 17AJX008 were typed as ST96, the same as serogroup badaviae. Conclusion:There are leptospirosis cases in epidemic area of Guizhou in high incidence season, grippotyphosa and bataviae are the newly discovered serogroups of Leptospira in Guizhou.