Application of PCR-RFLP technique on identification and genotyping of Brucella spp / 解放军医学杂志

ABSTRACT

Objective To amplify the 16S RNA fragments of 7 clinically isolated strains of Brucella spp. by PCR-RFLP technique, so as to provide experimental basis for the studies on diagnostics, genetics and epidemiology of Brucella spp. Methods According to the gene sequence of ATCC 25840 standard strain in GenBank, special primers for the 16S RNA conservative area in the Brucella spp. were designed. DNA extraction and PCR amplification of the 16S RNA fragments were performed with the 7 isolated strains. PCR products were then sequenced and RFLP analysis was conducted with appropriate restricted enzymes to study the homology and the mutation sites in those strains. Meanwhile, the clinical data of infected patients were retrospectively analyzed to evaluate the relationship between the clinical features and genotypes of Brucella infection. Results The amplified target fragments were about 1500bp in length and consistent with what was expected. The sequencing and homology analysis showed a 98.88% homology and 11 mutation sites among the 7 isolated strains. Four genotypes were identified by RFLP. Retrospective analysis of the clinical data indicated that no obvious relationship existed between the genotypes and the clinical features. Conclusions Amplifying 16S RNA fragments by PCR technique is a feasible method to make an early diagnosis of Brucella infection. The 7 clinically isolated strains are different in genotypes and 16S RNA fragment is a highly conservative fragment in bacterial genome with some mutations. The research provides evidence for the genetics and epidemiology of brucellosis.