MLVA Genotyping Characteristics of Human Brucella melitensis Isolated from Ulanqab of Inner Mongolia, China

Abstract

Brucellosis is a serious public health problem in Ulanqab, which is a region located in the middle of the Inner Mongolia Autonomous Region adjacent to Shanxi and Hebei provinces. The disease is prevalent in both the latter provinces and Ulanqab with the highest prevalence of brucellosis occurring in Inner Mongolia. The MLVA-16 scheme is a genotyping tool for assessing genetic diversity and relationships among isolates. Moreover, this genotyping tool can also be applied to epidemiological trace-back investigations. This study reports the occurrence of at least two B. melitensis biovars (1 and 3) in Ulanqab, encompassing 22 and 94 isolates, respectively. B. melitensis biovar 3 was the predominant biovar in the area examined. Panel 1 (MLVA-8) identified three genotypes (42, 63, and 114), with genotype 42 (n = 101) representing 87% of the tested strains. MLVA-11 identified eight genotypes (116, 111, 297, 291, and 342–345) from 116 of the analyzed isolates. All of these isolates were identified as belonging to the East Mediterranean group. Genotype 116 (n = 94) was the predominant genotype and represented 81% of the isolates. The isolates pertaining to this genotype were distributed throughout most of Ulanqab and neighboring regions. The MLVA-16 scheme showed the presence of 69 genotypes, with 46 genotypes being represented by single isolates. This analysis revealed that Ulanqab brucellosis cases had epidemiologically unrelated and sporadic characteristics. The remaining 23 genotypes were shared (between a total of 70 isolates) with each genotype being represented by two to eight isolates. These data indicate that these cases were epidemiologically related. MLVA genotyping confirmed the occurrence of a multipoint outbreak epidemic and intrafamilial brucellosis. Extensive genotype-sharing events were observed among isolates from different regions of Ulanqab and from other provinces of China. These findings suggest either a lack of control of animal movement between different regions or the circulation of contaminated animal products in the market. Our study is the first comprehensive genotyping and genetic analysis of B. melitensis in Ulanqab. We believe that this study will help to improve the effectiveness of brucellosis control programs.

Investigation of the molecular epizootiological characteristics and tracking of the geographical origins ofBrucella canisstrains in China

“…There were at least two alleles for each of the 16 loci investigated by the MIVA approach, which is different from the results of studies of B. melitensis diversity in China. For B. melitensis , the Bruce06, Bruce08, Bruce11, Bruce12, Bruce42 and Bruce45 loci of panel 1 and the Bruce18 locus of panel 2A each showed only one allele (HGDI = 0), and the Bruce04 locus displayed the highest diversity (Liu et al, ). Similarly, Jianghai et al reported that both Bruce16 and Bruce30 in the panel 2B markers were most useful for typing B. melitensis strains from China (H. Jiang et al, ).…”

Molecular epidemiological characterization ofBrucellaisolates from sheep and yaks in northwest China

“…Multilocus variable‐number tandem‐repeat analysis‐11 of 66 isolates found a novel genotype (genotype 369: 1‐5‐3‐13‐2‐2‐3‐2‐7‐41‐8), which emerged in panel 2B when the isolates were compared with other strains from different regions in China (Liu et al., ; Tian et al., ). The analysis indicated a dominant Brucella genotype that was relatively stable, but variations emerged in panel 2B within the bruce04, bruce16 and bruce30 loci.…”

“…Conversely, lower genetic diversity and crowding effects may favour transmission and select for faster replicating organisms with major zoonotic potential (Moreno, ). Therefore, the epidemic of brucellosis in animals may increase the prevalence of extensive cases, especially with a massive outbreak in Inner Mongolia, threatening thousands of people (Hou et al., ; Liu et al., ). Furthermore, comparing the 66 isolates from this study with 600 strains isolated from different animals and humans throughout China indicated that animal brucellosis exhibited almost the same epidemiological characteristics in different regions, suggesting these strains may be epidemiologically linked (Tian et al., ).…”

“…Comparing the results of genotyping using the web‐based Brucella MLVA database (http://mlva.u-psud.fr/brucella/), the major genotype of the B. melitensis isolates in China, which mainly included human and animal isolates from Guangdong, Inner Mongolia, Guizhou, Shanxi, Xinjiang, Qinghai and Zhejiang provinces, was genotype 42 (panel 1) (Li et al., ; Liu et al., ; Ma et al., ; Sun et al., ). In this study, 71% (47 of 66) of the B. melitensis isolates were identified as genotype 42, consistent with the results of previous studies.…”

“…These strains were also utilized for a molecular epidemiological investigation of their transfer between livestock and humans. Moreover, MLVA‐11 was used to determine the phylogeographic relationships among the 66 isolates (Liu et al., ; Tian et al., ).…”