Identification and analysis of Brucella strain isolated in Qinghai Province in 2013

Abstract

Objective To identify three suspected strains of Bruce lla isolated in Qinghai Province in 2013.Methods From July to August in 2013,60 brucellosis samples of people and animals from 13 brucellosis endemic areas were collected in Qinghai Province,including 33 cattle and sheep abortion lambs and 27 brucellosis antibody positive blood samples of patients.The isolation and culture of pathogen test were carried out in the tissues of liver,spleen and lung from cattle and sheep abortion lambs and the serum samples from patients with brucellosis.After biochemical detection with gram staining,thionine and fuchsin dyes bacteriostasis test,A and M factors serum agglutination test and phage lysis,the tested strains were got.AMOS-PCR,multiplex-PCR and multiple-locus variable-number tandem-repeat analysis（MLVA）-16 were conducted to identify the types of the measured strains.Results Three tested strains were obtained from 60 brucellosis samples of people and animals by isolation and culture of pathogen test.The colonies were arranged in bulk,moist,round,slightly elevated,smooth,and colorless; the gram staining was negative; bacteria could grow in thionine and fuchsin dyes; A and M factors serum agglutination test were positive; Bk phage lysis test was positive,but Tb and Wb phage lysis tests were negative; the results of AMOS-PCR and multiplex-PCR of 3 tested strains were same to Brucella melitensis M5 ; the genetypes were clustered together with Brucella melitensis by MLVA-16 method.Conclusion Conventional typing test assisted with molecular techniques has confirmed that the isolated Brucella strains are Brucella melitensis type 3. Key words: Brucella; Blood; Sequence analysis