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Veterinary Microbiology Apr 2016Although treponemes are consistently identified in tissue from bovine digital dermatitis (DD) lesions, the definitive etiology of this debilitating polymicrobial disease...
Although treponemes are consistently identified in tissue from bovine digital dermatitis (DD) lesions, the definitive etiology of this debilitating polymicrobial disease is still unresolved. To study the microbiomes of 27 DD-infected and 10 healthy interdigital skin samples, we used a combination of different molecular methods. Deep sequencing of the 16S rRNA gene variable regions V1-V2 showed that Treponema, Mycoplasma, Fusobacterium and Porphyromonas were the genera best differentiating the DD samples from the controls. Additional deep sequencing analysis of the most abundant genus, Treponema, targeting another variable region of the 16S rRNA gene, V3-V4, identified 15 different phylotypes, among which Treponema phagedenis-like and Treponema refringens-like species were the most abundant. Although the presence of Treponema spp., Fusobacterium necrophorum and Porphyromonas levii was confirmed by fluorescence in situ hybridization (FISH), the results for Mycoplasma spp. were inconclusive. Extensive treponemal epidermal infiltration, constituting more than 90% of the total bacterial population, was observed in 24 of the 27 DD samples. F. necrophorum and P. levii were superficially located in the epidermal lesions and were present in only a subset of samples. RT-qPCR analysis showed that treponemes were also actively expressing a panel of virulence factors at the site of infection. Our results further support the hypothesis that species belonging to the genus Treponema are major pathogens of DD and also provide sufficient clues to motivate additional research into the role of M. fermentans, F. necrophorum and P. levii in the etiology of DD.
Topics: Animals; Biodiversity; Cattle; Cattle Diseases; Digital Dermatitis; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Microbiota; RNA, Ribosomal, 16S; Skin; Virulence Factors
PubMed: 27016768
DOI: 10.1016/j.vetmic.2016.03.003 -
Journal of Clinical Microbiology Mar 2015A yet-undescribed bacterial species, tentatively named "Porphyromonas katsikii," was isolated from individuals of a small goat herd with pyogranulomatous pneumonia...
A yet-undescribed bacterial species, tentatively named "Porphyromonas katsikii," was isolated from individuals of a small goat herd with pyogranulomatous pneumonia during an outbreak of acute respiratory disease. The isolated bacteria grew in the form of black-pigmented colonies after 14 days of incubation under anaerobic conditions at 37°C on a tryptic soy blood agar medium. The bacteria were identified as a yet-undescribed Porphyromonas species by determination of the nucleotide sequence of the rrs 16S rRNA gene, and this species was tentatively named Porphyromonas katsikii. PCR amplification with specific primers for this yet-undescribed species revealed the presence of P. katsikii in the lung tissue of all affected animals, while no PCR signals were evidenced from the lungs of healthy goats or from goats with pasteurellosis caused by Mannheimia haemolytica. These data indicate P. katsikii as the causative agent of acute respiratory distress. P. katsikii is phylogenetically related to Porphyromonas somerae and Porphyromonas levii, which cause pathologies in humans and animals, respectively. P. katsikii was not detected by PCR from samples of the gingival pockets or of the faces of healthy goats.
Topics: Anaerobiosis; Animals; Bacteriological Techniques; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Disease Outbreaks; Goat Diseases; Goats; Lung; Molecular Sequence Data; Phylogeny; Pigments, Biological; Pneumonia, Bacterial; Porphyromonas; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Temperature
PubMed: 25540395
DOI: 10.1128/JCM.02682-14