Bacteriology

Topics of Interest

• Contagious equine metritis (CEM)
• Johne's disease information
• Johne's pooled fecal PCR
• Johne's Direct Fecal PCR
• Milk Quality
• Moraxella bovoculi
• Mycoplasma bovis - Real-time PCR test
• Mycoplasma hyosynoviae and Mycoplasma hyorhinis PCR - new 05/2009
• Pinkeye in Cattle
• Salmonella enteritidis
• Tritrichomonas foetus - new PCR test 3/30/09

Johne's Direct Fecal PCR

The Iowa State University Veterinary Diagnostic Laboratory is now offering qualitative direct fecal PCR testing for the detection of Mycobacterium avium var paratuberculosis DNA in bovine feces.  Results are available in 3-5 days compared with the eight weeks required for liquid fecal culture testing. Sensitivity for the direct PCR is comparable to the culture system for high- and moderate-shedding animals. The test is also highly specific for detecting MAP DNA and is able to discriminate between Mycobacterium avium var paratuberculosis and other fecal Mycobacteria species. 

Collect feces directly from the rectum if possible. Place at least 2 grams (1 tablespoon) into sterile plastic container. Use permanent marker to label vial with animal ID. Submit cooled samples to the ISU VDL as soon as possible. Do not freeze. 

Moraxella bovoculi 

Moraxella bovoculi is a recently described novel Moraxella species that in one study has been the only bacterial isolate obtained from approximately one-half of the IBK affected corneas of cattle in California. (Angelos JA, et al. Int J Syst Evol Microbiol 2007;57:789) Cultures obtained from the ocular surface of both normal and IBK affected cattle located here in the Midwest have confirmed the presence of this organism. At the present time, no successful attempts to fulfill Koch's postulates with this species have been documented and its role in the pathophysiology of IBK remains unclear.  Reevaluation of previous ocular cultures has revealed that many of the isolates previously classified as M. ovis (formerly Branhamella ovis) are actually M. bovoculi, however M. ovis does still remain a distinct species and may occasionally be isolated from the ocular surface of cattle. 

Currently the ISU VDL is using biochemical tests to differentiate M. bovoculi from M. ovis.  A small number of isolates for which biochemical tests were unable to appropriately speciate the isolates have been reported in the literature.  Thus, when differentiation of M. ovis and M. bovoculi is critical, confirmatory molecular differentiation of these isolates may be warranted.  Clients will note the classification of the Moraxellae to Moraxella bovis, Moraxella ovis and/or Moraxella bovoculi in our reporting in future cases of IBK.  At this time, the identification at ISU VDL does not include PCR testing, but the isolates can be forwarded for PCR testing at other facilities. 

Please address questions regarding this organism to Dr. Annette O'Connor (515-294-5012), Dr. Paul Plummer (515-294-8522), Dr. Vickie Cooper (515-294-1950) or Joann Kinyon (515-294-1950).