MLVA genotyping of Chinese human Brucella melitensisbiovar 1, 2 and 3 isolates

Hai Jiang,Mengguang Fan,Xiaoling Deng,Hongyan Zhao,Buyun Cui,Guozhong Tian,Jingdiao Chen,Changwen Ke,Dongri Piao,Ruiping Yu,Jingchuan Mi

doi:10.1186/1471-2180-11-256

Abstract

BackgroundSince 1950, Brucella melitensis has been the predominant strain associated with human brucellosis in China. In this study we investigated the genotypic characteristics of B. melitensis isolates from China using a multiple-locus variable-number tandem-repeat analysis (MLVA) and evaluated the utility of MLVA with regards to epidemiological trace-back investigation.ResultsA total of 105 B. melitensis strains isolated from throughout China were divided into 69 MLVA types using MLVA-16. Nei's genetic diversity indices for the various loci ranged between 0.00 - 0.84. 12 out 16 loci were the low diversity with values < 0.2 and the most discriminatory markers were bruce16 and bruce30 with a diversity index of > 0.75 and containing 8 and 7 alleles, respectively. Many isolates were single-locus or double-locus variants of closely related B. melitensis isolates from different regions, including the north and south of China. Using panel 1, the majority of strains (84/105) were genotype 42 clustering to the 'East Mediterranean' B. melitensis group. Chinese B. melitensis are classified in limited number of closely related genotypes showing variation mainly at the panel 2B loci.ConclusionThe MLVA-16 assay can be useful to reveal the predominant genotypes and strain relatedness in endemic or non-endemic regions of brucellosis. However it is not suitable for biovar differentiation of B. melitensis. Genotype 42 is widely distributed throughout China during a long time. Bruce 16 and bruce 30 in panel 2B markers are most useful for typing Chinese isolates.

Highlights

Since 1950, Brucella melitensis has been the predominant strain associated with human brucellosis inChina
In China, B. melitensis was the predominant strain associated with human brucellosis outbreaks, according to annual report on surveillance of
We report a case of brucellosis affecting a hospital microbiology laboratory technician in Beijing, a nonendemic area of China

Summary

Introduction

Since 1950, Brucella melitensis has been the predominant strain associated with human brucellosis in. In this study we investigated the genotypic characteristics of B. melitensis isolates from China using a multiple-locus variable-number tandem-repeat analysis (MLVA) and evaluated the utility of MLVA with regards to epidemiological trace-back investigation. Brucellosis, recognized as a common zoonotic disease globally, is caused by bacteria of the genus Brucella. B. melitensis, B. abortus, and B. suis remain the principal causes of human brucellosis worldwide and are major public health problems, primarily in Africa, the Middle. 30,000 human cases are reported annually over the past 5 years [2]. In China, B. melitensis was the predominant strain associated with human brucellosis outbreaks, according to annual report on surveillance of. Full list of author information is available at the end of the article selected infectious disease and vector. Species identification and subtyping of Brucella isolates is very important for epidemiologic surveillance and investigation of outbreaks in Brucella-endemic regions [3,4]

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Conclusion