title: The effect of tetronasin and monensin on fermentation, microbial numbers and the development of ionophore-resistant bacteria in the rumen.
abstract: The Gram-negative rumen bacteria Fibrobacter succinogenes S85, Prevotella ruminicola M384 and Veillonella parvula L59 were grown in media containing successively increasing concentrations of the ionophores, monensin and tetronasin. All three species became more resistant to the ionophore with which they were grown. Increased resistance to one ionophore caused increased resistance to the other, and cross-resistance to another ionophore--lasalocid--and an antibiotic--avoparcin. Recovery of tetronasin-resistant bacteria from the rumen of monensin-fed sheep increased and vice versa, indicating that similar cross-resistance occurred in vivo.
authors.affiliation: Rowett Research Institute, Bucksburn, Aberdeen, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Newbold
authors.forename: R J
authors.initials: RJ
authors.lastname: Wallace
authors.forename: N D
authors.initials: ND
authors.lastname: Walker
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001439:Bacteroides / Q000187:drug effects* / Q000254:growth & development; D015169:Colony Count, Microbial; D004352:Drug Resistance, Microbial; D005285:Fermentation / Q000187:drug effects; D005663:Furans / Q000494:pharmacology; D006089:Gram-Negative Anaerobic Bacteria / Q000187:drug effects* / Q000254:growth & development; D007476:Ionophores / Q000494:pharmacology*; D008985:Monensin / Q000494:pharmacology*; D012417:Rumen / Q000382:microbiology*; D012756:Sheep; D014678:Veillonella / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D005663:Furans; D007476:Ionophores; D008985:Monensin; C055416:tetronasin