Genotyping of Brucella abortus isolated in Gyeongbuk province by PFGE

Subtyping of Brucella abortus isolates is epidemiologically important for monitoring of bovine brucellosis outbreaks. Pulsed-field gel electrophoresis (PFGE) is considered as a gold standard of molecular typing methods to study the DNA polymorphisms of bacteria. In this study, we analyzed using PFGE the DNA fragment profiles of B. abortus isolated in Gyeongbuk province from 1998 to 2006. The genomic DNA was digested with the restriction endonuclease Xba I, Xho I and Smi I followed gel electrophoresis. No distinguishable patterns of the genomic DNA digested with Xba I and Xho I were observed among the field isolates of B. abortus tested in this study. But Smi I restriction enzyme resulted in two PFGE patterns consisting of 13-15 bands that ranged in size from 33 to 668bp by standard marker. The cluster analysis by DNA fingerprinting software showed 93.75% similarity between two PFGE patterns. No different PFGE patterns were recognized among the isolates originated from various years, regions and cow breeds.