Effect of biotin antagonists and related substances upon the growth of the coagulase-negative staphylococci

Abstract

The biotin activity, or anti-biotin properties of a number of substances, was
tested on a group of biotin-requiring, coagulase-negative Staphylococcus strains. Of the 18 cultures tested desthiobiotin served as a source of biotin for 17 strains. This substance appeared to be 40 per cent as active as biotin in supporting growth for two of the cultures tested. This substance possessed antibiotin properties for one strain (S19). Homobiotin, one of the chemical homologs of biotin, served as a biotin source for 17 of the 18 strains. Its activity appeared to be less than 0.1 percent of that of biotin among the 8 strains tested. Although it replaced biotin in high concentrations, small quantities appeared to possess anti-biotin properties for one of the Staphylococcus strains. Homobiotin acted as an ariti-biotin substance for strain S36 in all concentrations tested. In contrast 'to studies reported on other biotin-requiring microorganisms, there appeared to be no stoichiometric relationship between biotin and avidin in the nutrition of Staphylococcus, strain H17C. Upon adding increasing increments of egg white to a medium containing a limited amount of biotion, growth was unaffected until a critical concentration of avidin was reached. At this level little or no growth of the microorganism occurred. At higher levels growth again occurred, the amount depending directly upon the level of egg white added. All Staphylococcus cultures tested (18 strains) were able to utilize biocytin in place of biotin. On a molar basis this substance appeared to have an activity equal to that of biotin. Strain S36 failed to grow in a biotin deficient medium to which 0.1 percent Tween 80 was added. All other strains tested were able to grow under these conditions. In comparison with other strains culture H10A appeared to require approximately 100 times as much biotin for growth. This high requirement could be demonstrated in spite of the fact that the culture was able to grow to a limited degree in the absence of added biotin. This culture also demonstrated similar high requirements for biocytin, homobiotion, and desthiobiotin in a biotin free medium.