Open AccessAntimicrobial Activity of Gallium Nitrate against Mycobacterium avium subsp. paratuberculosis in Neonatal Calves
Author(s) -
Fecteau M.E.,
Whitlock R.H.,
Fyock T.L.,
McAdams S.C.,
Boston R.C.,
Sweeney R.W.
Publication year - 2011
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.2011.0768.x
Subject(s) - paratuberculosis , antimicrobial , medicine , feces , mycobacterium , adverse effect , microbiology and biotechnology , zoology , veterinary medicine , biology , tuberculosis , pathology
Background:Mycobacterium avium subsp. paratuberculosis (MAP), the agent of Johne's disease in cattle, is a facultative intracellular bacterium that is dependent on ferric iron for its survival and replication. Gallium (Ga), a trivalent semimetal that shares many similarities with ferric iron and functions as an iron mimic has been shown to have in vitro antimicrobial activity against several microorganisms, including MAP.Objectives: (1) To investigate the antimicrobial activity of Ga in calves experimentally infected with MAP; and (2) to monitor for potential adverse effects of Ga on calf health.Animals: Twelve Holstein calves.Methods: Randomized blind controlled experiment. Beginning at 10 days of age (study day 1), the experimental calves (n = 6) were treated with 20 mg/kg gallium nitrate daily for 45 days. On study days 4 and 5, all calves were challenged with a PO dose of a live field strain MAP. Treated calves were monitored daily for adverse effects. Calves were euthanized on study day 100, and 29 tissue samples and 1 fecal sample were collected from each calf. Samples were cultured for MAP by MGIT liquid culture system, Herrold's Egg Yolk Medium culture, or both.Results: No adverse effects were observed in the treated calves. Treatment was associated with a significant reduction in MAP tissue burden when compared with control calves ( P = .017).Conclusions and Clinical Relevance: Chemoprophylactic treatment of calves with Ga before and during the period of high susceptibility decreased MAP tissue colonization in experimentally infected neonatal calves.