摘要目的：应用多位点可变数目串联重复序列分型（ multiple locus variable number tandem repeat analysis ， MLVA）技术，初步探讨广东地区羊种3型布鲁氏菌的基因多态性特征分布。方法采用MLVA-16分型技术对广东地区患者分离的羊种3型布鲁氏菌株进行PCR 扩增、琼脂糖凝胶电泳和毛细管电泳等技术，并应用Bio Numerics（Version 5．0）软件进行布鲁氏菌基因多态性研究。结果43株布鲁氏菌菌株间的MLVA分型相似值介于68．2％～100％，在100％的水平上分成32种基因型别，其中27株（62．8％）为单一基因型，另外16株（37．2％）分属于其他5种基因型，各基因型分别含2～5株菌。结论广东地区羊种3型布鲁氏菌MLVA基因型呈现多态性分布特征，没有出现优势基因型别，单一特有基因型占了62．8％。

abstractsObjective To investigate the polymorphism of Brucella melitensis biovar 3 ( B.melitensis biovar 3) strains isolated from Guangdong province .Methods PCR assays followed by agar-ose gel electrophoresis and capillary electrophoresis based on the multiple locus variable number of tandem repeats (VNTR) analysis (MLVA) were performed to analyze 43 clinic isolates of B.melitensis biovar 3 strains isolated from clinical patients in Guangdong province .Results MLVA typing showed that the simi-larities of the analyzed locus among 43 strains of Brucella ranged from 68.2%to 100%.32 genotypes identi-fied among the isolates were identical (100%similarity).27 out of 43 strains (62.8%) were single geno-types, while the other 16 strains (37.2%) belonged to 5 other genotypes with 2 to 5 strains in each of them . Conclusion B.melitensis biovar 3 isolates showed polymorphism distribution in Guangdong province as in-dicated by MLVA typing analysis .Single-genotype isolates accounted for 62.8% of all studied strains.No predominant genotype was found among all isolates .