[Molecular typing on Leptospira interrogans isolates from Jiangxi province, by pulsed-field gel electrophoresis]

To perform a molecular epidemiological investigation on the types of Leptospira interrogans isolates from leptospirosis patients and animal hosts in Jiangxi province, using a pulsed-field gel electrophoresis (PFGE).

The extracted chromosomal DNA from leptospiral isolates were digested with restriction endonuclease Not I and the DNA segments were separated by using PFGE. By BiOnurerics V4.0 software and 75% similarity as the standard, the obtained PFGE images from leptospiral isolates were managed to establish a digitization database and then the PFGE maps of leptospiral isolates were compared with those of reference standard strains belonging to 15 serovars in 15 serogroups of L. interrogans, for cluster analysis.

139 strains of L. interrogans isolated from different areas of Jiangxi province were classified into 46 PFGE types. Among the PFGE types, LepNot I.0071, LepNot I.0072 and LepNot I.0043 were the predominant types that accounting for 28.06%, 15.11% and 7.19% of all the leptospiral isolates, respectively. The PFGE maps from 84.89% (118/139) of the 139 leptospiral isolates were found to basically match those of 6 reference standard strains belonging to 6 serovar in 6 serogroups of L. interrogans. In the 118 matched leptospiral isolates, 32.37% (45 strains), 15.83% (22 strains) and 15.11% (21 strains) belonged to sero-groups Icterohaemorrhagiae serovar Lai, sero-groups Australis serovar Australis and sero-group Javanica serovar Javanica, respectively.

PFGE seemed a fast, accurate and effective method for typing of L. interrogans isolates. Serogroup Icterohaemorrhagiae serovar Lai and followed by serogroup Australis serovar Australis as well as serogroup Javanica serovar Javanica were the predominant L. interrogans species in humans and animal hosts in Jiangxi province.