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.
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. ovisand 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).