Inhibition, resistance development, and increased antibiotic and antimicrobial resistance caused by nutraceuticals.

With the increasing use of herbal remedies by the general public worldwide, there remains a lack of information on the relationship between nutraceutical use and antibiotic resistance. Historically, there have been claims that nutraceuticals possess antibacterial and antiviral activity. However, the claims come with little or no documentation and no information related to the development of resistance to the nutraceutical or the cause of increases in resistance to antibiotics. These studies investigate the ability of nutraceutical exposure to influence the development of antibiotic resistance in bacteria. Two antibiotic-sensitive organisms, Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922, were used as representative of the gram-positive and gram-negative bacteria. These preliminary investigations showed a general increase to the ampicillin marker by the products studied, using Staphylococcus aureus ATCC 29213 as the indicator organism. There were 13 product-related increases in the MIC, 2 decreases, and 7 no changes. All six of the garlic products increased the MIC of the norfloxacin marker to greater than fourfold above baseline. Using E. coli ATCC 25922 as the indicator organism, the greatest product-antibiotic marker interaction was with the ampicillin marker. Garlic, Echinacea, and zinc products all caused large increases in the MIC to ampicillin over baseline values.