|ELLIOTT, MARGARET - Iowa State University|
|ZUERNER, RICHARD - Retired ARS Employee|
Submitted to: BMC Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2013
Publication Date: 12/5/2013
Publication URL: http://handle.nal.usda.gov/10113/58913
Citation: Wilson-Welder, J.H., Elliott, M.K., Zuerner, R.L., Bayles, D.O., Alt, D.P., Stanton, T.B. 2013. Biochemical and molecular characterization of Treponema phagedenis-like spirochetes isolated from a bovine digital dermatitis lesion. BMC Microbiology. 13:280. Available: http://www.biomedcentral.com/content/pdf/1471-2180-13-280.pdf.
Interpretive Summary: Bovine digital dermatitis (DD) causes lameness in cattle and associated economic losses. The incidence of DD is increasing although the cause of the syndrome is unknown. It is believed that Treponema bacteria may play a role in development of DD. In this study, we characterized of Treponema phagedenis isolates obtained from DD lesions from an Iowa dairy herd and compared them to sequences of other T. phagedenis type strains to see if characteristics may explain differences in host preference or pathogenicity. Employing classical bacteriology culture, enzymology and fatty acid production analysis, our data showed that our DD isolates were identical in enzyme profile and fatty acid production to type strains of T. phagedenis, but different from the other Treponema species tested. As a result of these analyses, a new media was developed for culture of Treponema. The genomic sequence of one T. phagendenis isolate was compared to the sequence of a human T. phagedenis isolate (strain F0421) and our data suggests that they are the same. Based on this data, T. phagedenis should also be considered to colonize bovine DD lesions.
Technical Abstract: Bovine papillomatous digital dermatitis (DD) is the leading cause of lameness in dairy cattle and represents a serious welfare and economic burden. Found primarily in high production dairy cattle worldwide, DD is characterized by the development of an often painful red, raw ulcerative or papillomatous lesion frequently located above the bulbs of the heel. While the exact etiology is unknown, several spirochete species have been isolated from lesion material. Treponema phagedenis-like bacteria were isolated from dairy cows in Iowa and given the designation strains 1A, 3A, 4A, and 5B (Trott et al., 2003). T. phagedenis has generally been described as a commensal of normal human genitalia. Given the distinct differences in host, environmental niche, and disease association, a closer analysis of phenotypic characteristics, growth characteristics, and genomic sequences of T. phagedenis and DD isolates was undertaken. Phenotypic characteristics of the Iowa isolates are similar to those of Treponema phagedenis strain Kazan. These strains range from 8.0 to 9.7 µm in length with 6-8 flagella on each end. These strains, like T. phagedenis, are strictly anaerobic, require serum and volatile fatty acids for growth, and are capable of fermenting fructose, mannitol, pectin, mannose, ribose, maltose, and glucose. Major glucose fermentation products produced are formate, acetate, and butyrate. Further study was conducted with a single strain, 4A. 4A has an optimal growth pH of 7.0 (range of 6-8.5) and an optimal growth temperature of 40ºC (range of 29ºC-43ºC). Comparison of partial genomic contigs of strain 4A and contigs of T. phagedenis strain F0421 revealed > 95% amino acid sequence identity with amino acid sequence of 4A. In silico DNA-DNA whole genome hybridization and BLAT analysis indicated a DDH estimate of >80% between strain 4A and T. phagedenis F0421, and estimates of 52.5% or less when compared to the fully sequenced genomes of other treponeme species. Based on the lack of difference between T. phagedenis and strain 4A, the description of Treponema phagedenis should be expanded from human genital skin commensal to include being an inhabitant within DD lesions in cattle.