摘要
Objective To study the types of subspecies of Francisella tularensis from China and to investigate the genetic relationships between F. tularensis strains from China and from other countries. Methods Ten strains of F. tulorensis isolated from China were amplified by using typing primers Cl/C4 and RD1. On the basis of the lengths of the polymerase chain reaction （PCR） products, it was concluded that these strains of F. tularensis belonged to the same subspecies. At the same time, thefopA, tul4, and 16S rRNA genes of the I0 strains were amplified, and a three-gene based phylogenetic analysis was performed using the Molecular Evolutionary Genetics Analysis software version 4.0. Results The 10 strains of F. tularensis from China were all identified as belonging to subspecies holarctica （type B）. We found no direct relationship between the genotypes of F. tulurensis subsp. holarctica and the geographical area from where they were isolated. Conclusion The F. tularensis strains isolated from North China mainly belong to subspecies holorctica （type B）. The strains of F. tularensis subsp, holarctico from China may have evolved earlier than those from Europe and North America.
Objective To study the types of subspecies of Francisella tularensis from China and to investigate the genetic relationships between F. tularensis strains from China and from other countries. Methods Ten strains of F. tulorensis isolated from China were amplified by using typing primers Cl/C4 and RD1. On the basis of the lengths of the polymerase chain reaction （PCR） products, it was concluded that these strains of F. tularensis belonged to the same subspecies. At the same time, thefopA, tul4, and 16S rRNA genes of the I0 strains were amplified, and a three-gene based phylogenetic analysis was performed using the Molecular Evolutionary Genetics Analysis software version 4.0. Results The 10 strains of F. tularensis from China were all identified as belonging to subspecies holarctica （type B）. We found no direct relationship between the genotypes of F. tulurensis subsp. holarctica and the geographical area from where they were isolated. Conclusion The F. tularensis strains isolated from North China mainly belong to subspecies holorctica （type B）. The strains of F. tularensis subsp, holarctico from China may have evolved earlier than those from Europe and North America.
基金
supported by the National Technology Key Special Study Program of the Eleventh Five‐year Plan (No. 2008ZX10004‐010)
