ConclusionThe findings reveal that pantoyltaurine, pyridine-3-sulfonic acid and pyrithiamine will inhibit the growth and acid production of the Lactobacillus acidophilus (Hadley) when present in sufficient concentrations in a medium containing all the known growth essentials of this organism. These metabolic analogues of pantothenic acid, nicotinic acid and thiamine have an affinity for enzymes or for the protein component of enzymes, substrates or the prosthetic groups which they resemble structurally.10 They tend to replace their corresponding essential nutrients in the metabolism of the Lactobacillus acidophilus (Hadley) and thereby interfere with its ability to carry on its normal physiological functions. The findings also confirm the previously reported observations that pantothenic acid, thiamine and nicotinic acid are essential for the maximum growth and acid production of the oral Lactobacillus acidophilus.