Extent of Mycobacterium bovis transmission among animals of dairy and beef cattle and deer farms in South Korea determined by variable-number tandem repeats typing

Novel Antibacterial Activity of Febuxostat, an FDA-Approved Antigout Drug against Mycobacterium tuberculosis Infection

Accumulating evidence suggests that drug repurposing has drawn attention as an anticipative strategy for controlling tuberculosis (TB), considering the dwindling drug discovery and development pipeline. In this study, we explored the antigout drug febuxostat and evaluated its antibacterial activity against Mycobacterium species. Based on MIC evaluation, we found that febuxostat treatment significantly inhibited mycobacterial growth, especially that of Mycobacterium tuberculosis (Mtb) and its phylogenetically close neighbors, M. bovis, M. kansasii, and M. shinjukuense, but these microorganisms were not affected by allopurinol and topiroxostat, which belong to a similar category of antigout drugs. Febuxostat concentration-dependently affected Mtb and durably mediated inhibitory functions (duration, 10 weeks maximum), as evidenced by resazurin microtiter assay, time-kill curve analysis, phenotypic susceptibility test, and the Bactec MGIT 960 system. Based on these results, we determined whether the drug shows antimycobacterial activity against Mtb inside murine bone marrow-derived macrophages (BMDMs). Notably, febuxostat markedly suppressed the intracellular growth of Mtb in a dose-dependent manner without affecting the viability of BMDMs. Moreover, orally administered febuxostat was efficacious in a murine model of TB with reduced bacterial loads in both the lung and spleen without the exacerbation of lung inflammation, which highlights the drug potency. Taken together, unexpectedly, our data demonstrated that febuxostat has the potential for treating TB.

Isolation of multidrug-resistant (MDR) Mycobacterium bovis from a dog in Korea

A 3-year-old female Miniature Schnauzer dog with a week-long history of generalized intention tremor and progressive weight loss for several months was admitted. Mild anemia, fever, splenomegaly, aseptic cerebral meningitis and systemic lymph nodes enlargement were examined through erythrogram, ultrasonography, computed tomography and magnetic resonance imaging. Mycobacterium bovis was identified via molecular microbiology having the same molecular type as that of isolates from a cattle farm previously identified. However, the dog was raised in a city. The M. bovis had multidrug resistance (MDR)-bearing mutations in both katG and rpoB genes toward first-line antibiotics. To the best of our knowledge, this is the first report describing an MDR M. bovis infection of a dog in Korea.

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

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.

Investigation of bovine tuberculosis outbreaks by using a trace-back system and molecular typing in Korean Hanwoo beef cattle

Bovine tuberculosis is a chronic contagious disease responsible for major agricultural economic losses. Abattoir monitoring and trace-back systems are an appropriate method to control bovine tuberculosis, particularly in beef cattle. In the present study, a trace-back system was applied to bovine tuberculosis cases in Korean native Hanwoo beef cattle. Bovine tuberculosis was detected in three index beef cattle during abattoir monitoring in Jeonbuk Province, Korea, and the original herds were traced back from each index cow. All cattle in each original herd were subjected to tuberculin skin test. The positive rates in the tuberculin skin test were 64.6% (62 of 96), 4.8% (2 of 42), and 8.1% (3 of 37) at farms A, B, and C, respectively. On post-mortem examination of 56 tuberculin-positive cattle, 62% had granulomatous lesions, and Mycobacterium bovis was cultured from 40 (71.4%) of the cattle. Molecular typing by spoligotyping and the mycobacterial interspersed repetitive unit-variable-number tandem repeat assay revealed the genotype of the M. bovis strains from the index cattle were same as the M. bovis genotype in each original herd. The results suggest that tracing back from index cattle to the original herd is an effective method to control bovine tuberculosis in beef cattle.

Epidemiology of Mycobacterium bovis and Mycobacterium tuberculosis in animals: Transmission dynamics and control challenges of zoonotic TB in Ethiopia

Mycobacterium tuberculosis complex is the cause of tuberculosis (TB) in humans and other animals. Specifically, Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis) are highly pathogenic mycobacteria that may infect different animal species and are the sources of TB in humans. The objective of this paper was to review the epidemiology of M. bovis and M. tuberculosis in animals. The review also highlighted the transmission dynamics of M. bovis and M. tuberculosis in humans and animals and control challenges of zoonotic TB in Ethiopia. The literature review focused on scientific peer-reviewed articles from studies exclusively conducted in Ethiopia that were published from 1998 to 2017. Husbandry system, breed and herd size have significant role in the epidemiology of bovine tuberculosis (BTB) in Ethiopia. The information presented reveals that different strains of M. bovis are widely distributed in domestic animals predominantly in the Ethiopian cattle and the main strain was found to be SB1176. In addition, the isolation of M. tuberculosis from domestic animals in different settings signifies the circulation of the agent between humans and animals in Ethiopia. The life styles of the Ethiopian communities, close contact with domestic animals and/or the habit of consuming raw animal products, are suggested as the main factors for transmission of M. bovis and M. tuberculosis between human and animal which may have impact on the TB control program in human. In Ethiopia, a human TB control program has been widely implemented, however, the role of animal in the transmission of the causative agent has been neglected which could be one of the challenges for an effective control program. This warrants the need for incorporating animal TB control programs using "One Health" approach for effective TB control for both human and animal.

Molecular and genomic features of Mycobacterium bovis strain 1595 isolated from Korean cattle

The aim of this study was to investigate the molecular characteristics and to conduct a comparative genomic analysis of Mycobacterium (M.) bovis strain 1595 isolated from a native Korean cow. Molecular typing showed that M. bovis 1595 has spoligotype SB0140 with mycobacterial interspersed repetitive units-variable number of tandem repeats typing of 4-2-5-3-2-7-5-5-4-3-4-3-4-3, representing the most common type of M. bovis in Korea. The complete genome sequence of strain 1595 was determined by single-molecule real-time technology, which showed a genome of 4351712 bp in size with a 65.64% G + C content and 4358 protein-coding genes. Comparative genomic analysis with the genomes of Mycobacterium tuberculosis complex strains revealed that all genomes are similar in size and G + C content. Phylogenetic analysis revealed all strains were within a 0.1% average nucleotide identity value, and MUMmer analysis illustrated that all genomes showed positive collinearity with strain 1595. A sequence comparison based on BLASTP analysis showed that M. bovis AF2122/97 was the strain with the greatest number of completely matched proteins to M. bovis 1595. This genome sequence analysis will serve as a valuable reference for improving understanding of the virulence and epidemiologic traits among M. bovis isolates in Korea.

Mycobacterium tuberculosis Infection in a Domesticated Korean Wild Boar ( Sus scrofa coreanus)

Tuberculosis, a chronic progressive disease, has been reported in bovine, swine, and primate species. Here, we report the first case of Mycobacterium tuberculosis infection in a Korean wild boar ( Sus scrofa coreanus). The owners this domesticated boar brought it to the Gyeongbuk Veterinary Service Laboratory in Korea after it was found dead and severely emaciated. Demarcated yellowish white nodules were found around the larynx and retropharyngeal lymph node during necropsy. The lungs had diffuse fibrinous pleuritis, severe congestion, and scattered nodules. More nodules were found in the spleen. Tuberculosis is characterized by massive macrophage infiltration and central caseous necrosis; both characteristics were found in the lungs. Histopathologic examination revealed that the alveolar lumen had marked fibrosis and exudates. Examination of the fluid revealed extensive macrophage permeation. To confirm a Mycobacterium infection, PCR was performed using two primer sets specific to the rpoB gene of Mycobacterium; Mycobacterium was detected in the lungs and spleen. To identify the species of Mycobacterium, immunohistochemical evaluation was performed using antibodies against Mycobacterium tuberculosis and Mycobacterium bovis . The results revealed immunoreactivity against M. tuberculosis but not against M. bovis . The consumption of undercooked or raw meat from game animals may expose humans and other animals to sylvatic infection. Consequently, Koreans who ingest wild boar may be at risk of a tuberculosis infection. To reduce the risk of foodborne infection and maintain public health, continuous monitoring and control strategies are required.

Isolation of Mycobacterium bovis from Free-Ranging Wildlife in South Korea

We demonstrate Mycobacterium bovis infection in wild boar ( Sus scrofa ) in South Korea. During 2012-15, we attempted to isolate M. bovis from 847 wild animals, mainly Korean water deer ( Hydropotes inermis argyropus), raccoon dogs ( Nyctereutes procyonoides ), and wild boar, from 11 regions in South Korea. We isolated M. bovis from three of 118 wild boar (2.5%) captured in Gyeonggi Province, where bovine tuberculosis (bTB) outbreaks have also occurred in livestock. Spoligotypes and mycobacterial interspersed repetitive units-variable number tandem repeats types of these M. bovis isolates (SB0140 and SB1040, 4-2-3-3-7-5-5-4-4-3-4-3 and 5-2-3-3-7-5-5-4-3-10-5-2; MIRU4, MIRU16, MIRU27, MIRU31, ETR-A, ETR-B, ETR-C, QUB11b, QUB26, QUB3336, VNTR2401, and VNTR3171) have also been identified from farmed livestock such as cattle ( Bos taurus coreanae), Formosan sika deer ( Cervus nippon taiouanus), and American elk ( Cervus canadensis ) in the country. In South Korea, bTB appears to be endemic in livestock, and there are numerous opportunities for contact between wild boar and livestock due to high population densities and broad activity ranges. Our results support the hypothesis that M. bovis is transmitted between domestic and wild animals.

Mycobacterium bovis infection in a wild sow (Sus scrofa): first case in Korea

Mycobacterium (M.) bovis causes tuberculosis and has a broad host range, including humans, livestock, and wild animals. M. bovis infection of wild boar has been reported in several European countries. We report here the first case of M. bovis infection in a domesticated wild sow in Korea. Granulomatous and necrotizing lesions with small numbers of acid-fast bacilli were observed in nodules of the lung of wild sow. Furthermore, the M. bovis isolate from the wild sow had spoligotype SB0140 and a novel MIRU-VNTR allelic profile, which is not found in cattle and deer in Korea.