Molecular typing of Salmonella Typhi isolates from six provinces with pulsed field gel electrophoresis

ObjectiveTo analyze the molecular types of Salmonella Typhi strains isolated from six provinces in China,and establish the PulseNet databank. MethodsPulsed field gel electrophoresis(PFGE) was used to analyze SalmonellaTyphi strains isolated from 6 provinces during 1979-2005.The genomic DNA in different Salmonella Typhi strains wereextracted after digesting with XbaⅠ. The BioNumerics software was used to analyze the PFGE patterns. ResultsPFGEpatterns of Salmonella Typhi strains isolated in China in different years were quite different. There were 288 PFGE patterns in total. The similarity value of the strains ranged from 55.2％ to 100％.The same patterns were discovered in different province and in different year. Conclusion Salmonella Typhi strains isolated in China varied, and different clones might exist in different provinces. The establishment of PulseNet database is of great significance for the surveillance of Salmonella Ttyphi strains in China.