This study analyzed the diversity and phylogenetic relationship of the microbiome of bovine digital dermatitis (BDD) lesions and normal skin from cattle foot by using 16S rRNA amplicon sequencing. Three BDD samples and a normal skin sample were pre-assessed for analysis. The Illumina Miseq platform was used for sequencing and sequences were assembled and were categorized to operational taxonomic units (OTUs) based on similarity, then the core microbiome was visualized. The phylogeny was inferred using MEGA7 (Molecular evolutionary genetics analysis version 7.0). A total of 129 and 185 OTUs were uniquely observed in normal and in BDD samples, respectively. Of the 47 shared OTUs, 15 species presented increased abundance in BDD. In BDD and normal samples, Spirochetes and Proteobacteria showed the most abundant phyla, respectively, suggesting the close association of observed species in each sample group. The phylogeny revealed the evolutionary relationship of OTUs and the Euclidean distance suggested a high sequence divergence between OTUs. We concluded that a shift in the microbiome leads to richer diversity in BDD lesions, and the overabundance of opportunistic pathogens and its synergistic relationship with commensal bacteria could serve as factors in disease development. The influence of these factors should be thoroughly investigated in future studies to provide deeper insights on the pathogenesis of BDD.
This study aimed to isolate and characterize Treponema spp. from bovine digital dermatitis (BDD)-infected dairy cattle. Seven isolates were characterized in this study. Isolates exhibited slow growth, and colonies penetrated the agar and exhibited weak β-hemolysis. Round bodies were observed in old and antibiotic-treated cultures. Cells ranged from 9–12 µm in length, 0.2–2.5 µm in width, and were moderately spiraled. The 16S rRNA analysis revealed the isolates as Treponema phagedenis with >99% sequence homology. Isolates had alkaline phosphatase, acid phosphatase, β-galactosidase, N-acetyl-β-glucosaminidase, esterase (C4), esterase lipase (C8), naphthol-AS-BI-phosphohydrolase, and β-glucuronidase activities. Low concentrations of ampicillin, erythromycin, and tetracycline were required to inhibit the growth of isolates. Formic, acetic, and butyric acids were produced, while propionic acid was significantly utilized, indicating its essentiality for treponemal growth. The isolates shared the same characteristics and, therefore, were considered as a single strain. Isolate HNL4 was deposited as a representative isolate (Treponema phagedenis KS1). The average nucleotide identity of strain KS1 showed a small difference with the human strain (99.14%) compared with bovine strain (99.72%). This study was the first to isolate and characterize Treponema phagedenis from BDD in Korea and, hence, it delivered pathogenicity-related insights and provided valuable information that can be used for the management of BDD.
The study characterized Trueperella pyogenes (T. pyogenes) from caseous lymphadenitis (CLA) in Korean native goats (KNG). CLA samples (n=191) were obtained from abattoir-slaughtered KNG. Pus were obtained and Corynebacterium pseudotuberculosis was detected by PCR using PLD gene. Three PLD-negative samples (1.57%) from supramammary lymph node were subjected to bacterial culture. Isolates were identified using 16S rRNA and biochemically characterized by APIZYM. Phylogenetic and biochemical analyses identified the isolates as T. pyogenes, and have shown separate clusters and varied enzyme reaction, suggesting genotypic and phenotypic diversity. This first report of T. pyogenes-induced CLA in KNG provided information for further investigations.
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