Peter Muir¹, William E Oldenhoff¹, Paul A.Manley¹, Susan L. Schaefer¹, Alan P. Hudson², Herve C Gerard², Mark D Markel1, Zhengling Hao¹.
¹University of Wisconsin-Madison, Madison, WI, United States, ²Wayne State University, Detroit, MI, United States

ACVS Abstract 2007

Mixtures of environmental bacteria within joints, including Stenotrophomonas maltophilia, have been implicated as a causative factor in the pathogenesis of arthritis. To further understanding of the pathogenesis of canine inflammatory stifle arthritis/degenerative cranial cruciate ligament (CCL) rupture, we analyzed specimens of synovium and synovial fluid from 130 dogs with CCL rupture over a 1-year period; synovium from 12 dogs with normal stifles and 14 dogs with experimentally-induced CCL rupture was also studied. Using non-nested PCR, specimens were tested for 16S rRNA bacterial DNA using ‘panbacterial’ consensus primers.

We also tested specimens for Borrelia burgdorferi OspA and Stenotrophomonas maltophilia 23S rRNA gene sequences, using non-nested and nested assays respectively. Overall, the presence of bacterial DNA within the stifle was associated with the CCL rupture arthropathy (Po0.05); 74% of joints were PCR-positive. Seasonal variation in detection of 16S rRNA and OspA was found; OspA was mainly found in the spring and summer, whereas 16S rRNA sequences were mainly found in the fall and winter. Using the more sensitive nested 23S rRNA assay, Stenotrophomonas DNA was found throughout the year and was also detected in experimental dogs with induced CCL rupture.

These data implicate environmental bacteria, such as Stenotrophomonas maltophilia, as a causative factor for chronic stifle synovitis. Seasonal variation in detection of microbial DNA suggests an insect vector may be important for translocation of bacterial material to the stifle. Our data also suggest that the quantity of bacterial material within the stifle joint may be quite variable.