Mycobacterium bovis is a causal agent of bovine tuberculosis (bTB), one of the most important diseases currently facing the cattle industry worldwide. Tracing the source of M. bovis infections of livestock is an important tool for understanding the epidemiology of bTB and defining control/eradication strategies. In this study, whole genome sequencing (WGS) of 74 M. bovis isolates sourced from naturally infected cattle in the State of Rio Grande do Sul (RS), southern Brazil, was used to evaluate the population structure of M. bovis in the region, identify potential transmission events and date the introduction of clonal complex (CC) European 2 (Eu2). In silico spoligotyping identified 11 distinct patterns including four new profiles and two CCs, European 1 (Eu1) and Eu2. The analyses revealed a high level of genetic diversity in the majority of herds and identified putative transmission clusters that suggested that within- and between-herd transmission is occurring in RS. In addition, a comparison with other published M. bovis isolates from Argentina, Brazil, Paraguay and Uruguay demonstrated some evidence for a possible cross-border transmission of CC Eu1 into RS from Uruguay or Argentina. An estimated date for the introduction of CC Eu2 into RS in the middle of the 19th century correlated with the historical introduction of cattle into RS to improve existing local breeds. These findings contribute to the understanding of the population structure of M. bovis in southern Brazil and highlight the potential of WGS in surveillance and helping to identify bTB transmission.

/pdf/genomic-and-temporal-analyses-of-mycobacterium-bovis-in-4ahx1t7g1c.pdf

Genomic and temporal analyses of Mycobacterium bovis in southern Brazil.

Background Bovine tuberculosis (TB) is caused by Mycobacterium bovis, a well-known cause of zoonotic tuberculosis in cattle and deer, and has been investigated in many physiological and molecular studies. However, detailed genome-level studies of M. bovis have not been performed in Korea. Objectives To survey whole genome-wide single-nucleotide polymorphism (SNP) variants in Korean M. bovis field isolates and to define M. bovis groups in Korea by comparing SNP typing with spoligotyping and variable number tandem repeat typing. Methods A total of 46 M. bovis field isolates, isolated from laryngopharyngeal lymph nodes and lungs of Korean cattle, wild boar, and Korean water deer, were used to identify SNPs by performing whole-genome sequencing. SNP sites were confirmed via polymerase chain reaction using 87 primer pairs. Results We identified 34 SNP sites with different frequencies across M. bovis isolates, and performed SNP typing and epidemiological analysis, which divided the 46 field isolates into 16 subtypes. Conclusions Through SNP analysis, detailed differences in samples with identical spoligotypes could be detected. SNP analysis is, therefore, a useful epidemiological tracing tool that could enable better management of bovine TB, thus preventing further outbreaks and reducing the impact of this disease.

/pdf/single-nucleotide-polymorphism-based-epidemiological-bi79o40aby.pdf

Single-nucleotide polymorphism-based epidemiological analysis of Korean Mycobacterium bovis isolates

Bovine tuberculosis (bTB) has yet to be eradicated in Brazil. Herds of cattle and
buffalo are important sources of revenue to people living in the banks of the Amazon
River basin. A better understanding of Mycobacterium bovis (M. bovis) populational
structure and transmission dynamics affecting these animals can significantly contribute
in efforts to improve their sanitary status. Herein, we sequenced the whole genome
of 22 M. bovis isolates (15 from buffalo and 7 from cattle) from 10 municipalities in
the region of the Lower Amazon River Basin in Brazil and performed phylogenomic
analysis and Single Nucleotide Polymorphism (SNP)-based transmission inference to
evaluate population structure and transmission networks. Additionally, we compared
these genomes to others obtained in unrelated studies in the Marajo Island (n = 15)
and worldwide (n = 128) to understand strain diversity in the Amazon and to infer
M. bovis lineages. Our results show a higher genomic diversity of M. bovis genomes
obtained in the Lower Amazon River region when compared to the Marajo Island,
while no significant difference was observed between M. bovis genomes obtained
from cattle and buffalo (p ≥ 0.05). This high genetic diversity is reflected by the
weak phylogenetic clustering of M. bovis from the Lower Amazon River region based
on geographic proximity and in the detection of only two putative transmission
clusters in the region. One of these clusters is the first description of inter-species
transmission between cattle and buffalo in the Amazon, bringing implications to the
bTB control program. Surprisingly, two M. bovis lineages were detected in our dataset,
namely Lb1 and Lb3, constituting the first description of Lb1 in South America.
 Bovine tuberculosis (bTB) has yet to be eradicated in Brazil. Herds of cattle and
buffalo are important sources of revenue to people living in the banks of the Amazon
River basin. A better understanding of Mycobacterium bovis (M. bovis) populational
structure and transmission dynamics affecting these animals can significantly contribute
in efforts to improve their sanitary status. Herein, we sequenced the whole genome
of 22 M. bovis isolates (15 from buffalo and 7 from cattle) from 10 municipalities in
the region of the Lower Amazon River Basin in Brazil and performed phylogenomic
analysis and Single Nucleotide Polymorphism (SNP)-based transmission inference to
evaluate population structure and transmission networks. Additionally, we compared
these genomes to others obtained in unrelated studies in the Marajo Island (n = 15)
and worldwide (n = 128) to understand strain diversity in the Amazon and to infer
M. bovis lineages. Our results show a higher genomic diversity of M. bovis genomes
obtained in the Lower Amazon River region when compared to the Marajo Island,
while no significant difference was observed between M. bovis genomes obtained
from cattle and buffalo (p ≥ 0.05). This high genetic diversity is reflected by the
weak phylogenetic clustering of M. bovis from the Lower Amazon River region based
on geographic proximity and in the detection of only two putative transmission
clusters in the region. One of these clusters is the first description of inter-species
transmission between cattle and buffalo in the Amazon, bringing implications to the
bTB control program. Surprisingly, two M. bovis lineages were detected in our dataset,
namely Lb1 and Lb3, constituting the first description of Lb1 in South America. Most of the strains of this study (13/22) and all 15 strains of the Marajo Island carried no
clonal complex marker, suggesting that the recent lineage classification better describe
the diversity of M. bovis in the Amazon.

/pdf/genetic-diversity-and-potential-paths-of-transmission-of-2ww3n9ncl8.pdf

Genetic Diversity and Potential Paths of Transmission of Mycobacterium bovis in the Amazon: The Discovery of M. bovis Lineage Lb1 Circulating in South America.

Beatriz Romero Martínez

Papers

High discrimination of Mycobacterium bovis isolates in Brazilian herds by spoligotyping.