[Establishment of standardized method for pulsed-field gel electrophoresis on Leptospira interrogans and analysis on their patterns].

OBJECTIVE: To establish a standardized operation procedure for pulsed-field gel electrophoresis (PFGE) on Leptospira interrogans as well as a figure digital database to develop the Chinese representative reference strains. METHODS: Under the characteristics of strains and referring to the other SOPs of PFGE on pathogens provided by CDC and PulseNet Asia Pacific, genomic chromosome DNA purification, restriction endonuclease digestion and the parameters for running PFGE were optimized. RESULTS: Not I digestion patterns of leptospiral genome for the Chinese representative strains were established and partial isolates of serogroup icterohaemorrhagiae from the leptospirosis surveillance in Sichuan and Anhui provinces were analyzed by PFGE. Results showed that each of all the 15 Chinese representative strains had a unique pattern. 91.67% (22/24) of the 24 isolates identified as serogroup icterohaemorrhagiae matched to the map of the reference strain 56601 (serogroup icterohaemorrhagiae serovar lai). CONCLUSION: The PFGE figures were clear with high resolution and the fragments were equally distributed by this standardized operating procedure so as to reveal the molecular-genetic characteristics of Leptospira interrogans. The patterns had high relativity with the serological identification and seemed to be very important for genetic analysis of strains in studying the outbreak of leptospirosis.