title: Enumeration and confirmation of Clostridium tyrobutyricum in silages using neutral red, D-cycloserine, and lactate dehydrogenase activity.
abstract: Spores of clostridia in big bale silages, manure, and dairy products were enumerated and distinguished from other spore formers by using Reinforced Clostridium Agar containing .005% neutral red. Spores of Clostridium tyrobutyricum predominated, but spores of Clostridium butyricum, Clostridium sporogenes, Clostridium bifermentans, Clostridium putrificum, and Clostridium sphenoides occurred to a lesser extent. In samples with high bacterial spore counts, growth of Bacillus spp., but not C. tyrobutyricum, was retarded by the addition of 200 ppm D-cycloserine. Clostridia isolated from silages and milk products were identified and tested on lactate dehydrogenase activity. Of 275 investigated strains, only strains identified as C. tyrobutyricum tested positively. Only 65% of the tested strains of C. tyrobutyricum grew in the confirmatory substrate containing minerals, lactic acid, and acetic acid. Tyrobutyricum Broth was not selective for C. tyrobutyricum, since C. butyricum and C. sporogenes also grew in this medium.
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala.
authors.forename: A
authors.initials: A
authors.lastname: Jonsson
mesh_terms: D000821:Animal Feed; D000818:Animals; D001407:Bacillus / Q000254:growth & development; D003013:Clostridium / Q000254:growth & development*; D015169:Colony Count, Microbial; D003470:Culture Media; D003523:Cycloserine; D005516:Food Microbiology; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D009499:Neutral Red; D012820:Silage; D013171:Spores, Bacterial
chemical_list: D003470:Culture Media; D009499:Neutral Red; D003523:Cycloserine; D007770:L-Lactate Dehydrogenase