Evidence of Multiple Treponema Phylotypes Involved in Bovine Digital Dermatitis as Shown by 16S rRNA Gene Analysis and Fluorescence In Situ Hybridization

Abstract

The etiopathogenesis of the skin disease digital dermatitis (DD), an important cause of lameness in cattle, remains uncertain. Microscopically, the disease appears to be polymicrobial, with spirochetes as the predominant bacteria. The objective of this study was to identify the main part of the bacteria involved in DD lesions of cattle by using culture-independent molecular methods. Ten different phylotypes of Treponema were identified either by 16S rRNA gene sequencing of bacteria from DD lesions or by fluorescence in situ hybridization (FISH) analysis using phylotype-specific 16S rRNA-directed oligonucleotide probes. Two phylotypes, phylotype 1 (PT1) and PT2, were not closely related to any characterized treponemal species. PT7 was 99.3% identical to Treponema denticola, while PT9 resembled T. vincentii by 96%. The remaining phylotypes, PT3, PT4, PT5, PT6, and PT8, and Treponema brennaborense had previously been isolated from DD lesions. Forty DD biopsy specimens were examined for Treponema by FISH. With one exception, all of the biopsy specimens revealed epidermotropic, intermingled infection with three or more different phylotypes (mean, 4.7). The most prevalent species were PT1 (95%), PT6 (93%), and PT3 (85%). While colonization by PT3 was confined to the surface of the epidermis, both PT1 and PT6 invaded deep into the stratum spinosum and were seen in ulcerated dermal papillae. In two cases, all 10 phylotypes were demonstrated. Furthermore, FISH with a Treponema group-specific probe showed that Treponema accounted for more than 90% of the total bacterial population in the biopsy specimens. These data strongly suggest that a group of apparently symbiotic Treponema species are involved as primary bacterial pathogens in DD.

Association of Unique, Isolated Treponemes with Bovine Digital Dermatitis Lesions

“…This is not readily explainable, unless a symbiotic relationship is optimal for disease induction and maintenance. Symbiosis of treponemes in BDD lesions has been used to (17,23), and further research into such a symbiosis might be appropriate. As a result of this study, we may be one step closer to dissecting such a symbiotic pathogenesis given that we have been able to isolate members of all three groups from the same lesion.…”

Ovine pedomics: the first study of the ovine foot 16S rRNA-based microbiome

“…were detected in only one sheep with ID from flock C. There were two sequences and they had 94 and 99% similarity to uncultured Treponema phylotypes from samples from cattle with digital dermatitis and from animal faecal samples (Klitgaard et al, 2008;Ley et al, 2008). Treponema are often free living but are linked to contagious ovine digital dermatitis and bovine digital dermatitis in sheep and cattle, respectively (Collighan et al, 2000;Moore et al, 2005;Demirkan et al, 2006;Evans et al, 2008Evans et al, , 2009Sayers et al, 2009).…”

Virulence Factors of the Oral Spirochete Treponema denticola

“…Treponemes play a role in the etiology of several chronic diseases of humans including syphilis and yaws (Treponema pallidum), periodontal diseases including chronic periodontitis and acute necrotizing ulcerative gingivitis (Treponema denticola, Treponema lecithinolyticum, Treponema socranskii, and others), and endodontic infections and some acute dental abscesses (Sela, 2001;Foschi et al, 2006;Holt and Ebersole, 2006;Robertson and Smith, 2009). In addition, treponemes have been implicated in the development of chronic diseases of domestic animals, including periodontal diseases of dogs (Nordhoff et al, 2008b), bovine digital dermatitis of dairy cattle (Choi et al, 1997;Klitgaard et al, 2008;Nordhoff et al, 2008a), and contagious ovine digital dermatitis (Dhawi et al, 2005;Sayers et al, 2009).…”