Salmonella Is No Match For Thyme, Oregano, Or Clove Essential Oils, New Study Finds

Salmonella is a bacteria that usually just causes a nasty case of the the so-called "stomach bug," but as antibiotics become less useful in treating dangerous cases, researchers are now looking at essential oils as possible tools to fight this potentially deadly bacteria.

Usually, people who are sickened by salmonella recover, but sometimes people require hospitalization when they are infected with salmonella, especially infants, elderly adults, and people with impaired immune systems, according to the CDC. Salmonella can sometimes spread into the bloodstream from the intestines by ingesting contaminated food. If it makes it into the bloodstream, people can die if they are not treated with antibiotics. The only problem is that antibiotics are becoming less useful against all sorts of bacteria, so scientists have turned to nature for suitable replacements to traditional antibiotics and antimicrobials.

In science journals, researchers generally refer to the active compounds in essential oils. Many people curious about essential oils may not recognize the term carvacrol, but it is the active ingredient in oil of oregano. Eugenol is the active ingredient in clove oil. Thymol is the active ingredient in thyme oil.

Carvacrol, thymol, and eugenol are three of nature's strongest antimicrobials. All three of these compounds, found in their respective essential oils, are now recognized within the scientific community for their therapeutic potential, according to an article published last month in Microbial Pathogenesis.

The new research, published last month found the active components in thyme oil, oregano oil, and clove oil to be especially capable of wiping out Salmonella Typhimurium strains. Inquisitr readers might remember Salmonella Typhimurium as one of the types of bacteria responsible for the multi-state salmonella outbreak linked to contaminated cantaloupe a few years back.

The researchers involved in the new study also examined what effects carvacrol, thymol, and eugenol had on the efficacy of a common antibiotic. As it turned out, the active ingredients in oregano oil, thyme oil, and clove oil all enhanced the ability of the antibiotic to kick Salmonella Typhimurium to the curb, and this included synergistic effects against salmonella biofilm! In fact, there was a pronounced effect of lowering biofilm mass when the essential oil compounds were used. Thymol was the strongest at the lowest concentrations against the salmonella.

Thymol was the most effective of the essential oils, according to the researcher. The lowest minimum inhibitory concentration MICs values in which thymol was effective ranged from 32 to 128 μg/mL. The essential oils disrupted the samonella cellular membranes. The researchers wrote that "a complete loss of membrane integrity was also evident."

Another article published in International Journal of Food Microbiology found that carvacrol and thymol reduced biofilm of both S. aureus and Salmonella after just one minute! Of course, even with essential oils, it's important not to lower the dose so much that it falls below the minimum inhibitory concentration. Research that was published very recently indicated that even essential oils have the potential to induce bacterial biofilm production if used in concentrations that as too low to inhibit the bacteria.

Way back in the early nineties, researchers already saw antibiotic resistant salmonella, according to an article published in 1991 by International Journal of Food Microbiology.

"Clinical management of systematic infections with newer drugs such as third-generation cephalosporins and quinolones is most promising, particularly in light of the increasing resistance of Salmonella to the traditional ampicillin, chloramphenicol and trimethoprim sulfamethoxazole therapeutic agents."
At the time, scientists suggested only using antibiotics to treat difficult cases. Now, researchers need to find novel ways to fight bacteria like salmonella and MRSA. Scientists have turned, in part, to essential oils. Just as scientists warned of antibiotic resistance decades ago, some scientists are warning that over-diluted concentrations of essential oils might actually promote biofilm production. The hope if that this time, manufacturers and consumers will heed the warnings and use all antimicrobials, including essential oil-based antimicrobials, responsibly.

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