Thiamine requirement of Eikenella corrodens

The thiamine requirement for growth of Eikenella corrodens was investigated. Autoclaved thiamine at a concentration of 1.0 microgram/ml supported maximal growth whereas for the same growth, filter-sterilized thiamine was required at 50-100 micrograms/ml. Studies with two thiamine degradation products, 2-methyl-4-amino-5-hydroxymethylpyrimidine and 4-methyl-5-(B-hydroxyethyl) thiazole, indicated that selected strains grew poorly or not at all in the presence of either moiety alone. However, the two moieties at a combined concentration of 0.02 microgram/ml supported growth equivalent to that of 1.0 microgram/ml of autoclaved thiamine. The requirement for a high concentration of filter-sterilized thiamine may reflect a faulty thiamine uptake apparatus and the observed growth response may be due to the presence of the moieties in the commercial thiamine preparation.