Antibacterial activities of naturally occurring compounds against antibiotic-resistant Bacillus cereus vegetative cells and spores, Escherichia coli, and Staphylococcus aureus.
After demonstrating the lack of effectiveness of standard antibiotics against the acquired antibiotic resistance of Bacillus cereus (NCTC 10989), Escherichia coli (NCTC 1186), and Staphylococcus aureus (ATCC 12715), we showed that the following natural substances were antibacterial against these resistant pathogens: cinnamon oil, oregano oil, thyme oil, carvacrol, (S)-perillaldehyde, 3,4-dihydroxybenzoic acid (beta-resorcylic acid), and 3,4-dihydroxyphenethylamine (dopamine). Exposure of the three pathogens to a dilution series of the test compounds showed that oregano oil was the most active substance. The oils and pure compounds exhibited exceptional activity against B. cereus vegetative cells, with oregano oil being active at nanogram per milliliter levels. In contrast, activities against B. cereus spores were very low. Activities of the test compounds were in the following approximate order: oregano oil > thyme oil approximately carvacrol > cinnamon oil > perillaldehyde > dopamine > beta-resorcylic acid. The order of susceptibilities of the pathogens to inactivation was as follows: B. cereus (vegetative) >> S. aureus approximately E. coli >> B. cereus (spores). Some of the test substances may be effective against antibiotic-resistant bacteria in foods and feeds.
Friedman
Mendel
M
Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, California 94710, USA. mfried@pw.usda.gov
Buick
Robert
R
Elliott
Christopher T
CT
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects* / Q000254:growth & development; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D005516:Food Microbiology; D008826:Microbial Sensitivity Tests; D010938:Plant Oils / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents; D010938:Plant Oils