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How Honey Curbs the MRSA Superbug

Ker Than
for National Geographic News
September 8, 2009
 
A dark, bitter kind of honey can cripple infection-causing bacteria, including the highly virulent strain known as MRSA, and now researchers think they know how the honey fights the superbug.

Manuka honey is made when honeybees primarily consume the nectar of the manuka bush, a flowering plant native to Australia and New Zealand.

Researchers already knew that manuka honey has antibacterial properties, but why and how it works has been a mystery.

"Manuka honey has an extra [unidentified] component that isn't found in other honey, which gives it an extra kick," said study team member Rowena Jenkins of the University of Wales Institute, Cardiff.

"It may even be several components working together."

Honey Thief

In a new experiment, Jenkins and colleagues grew MRSA in the lab with and without manuka honey for four hours.

MRSA, or meticillin-resistant Staphylococcus aureus, is a type of staph infection that isn't affected by many common antibiotics.

(Related: "Drug-Resistant Staph Infection Spreads to Gyms, Day Care.")

The team also grew batches of MRSA with and without sugar syrup, to check whether the honey's high sugar content was solely responsible for fighting the bacteria.

In general, many bacteria can't grow in high-sugar environments, since the sugars tie up water that the bacteria need to survive. (Get more germ-filled facts with our infectious diseases quiz.)

Jenkins and colleagues found that the MRSA bacteria treated with manuka honey more often lacked a particular protein necessary for synthesizing fatty acids, which are required for building cell walls and internal structures.

The crippled bacteria "don't have the necessary proteins to complete their life cycles," Jenkins said, so they are unable to reproduce and eventually die.

Since the sugar syrup didn't have the same results, the researchers think some other, unidentified component must be disabling the bacteria.

Not Exactly on Store Shelves

Finding out more about manuka's mystery ingredient could lead to new treatments for drug-resistant bacteria strains, the study authors say.

Still, the researchers caution against treating wounds with commercially sold manuka honey.

Unlike medical-grade honey, store-bought honey is not sterilized and could contain microbes and spores that might make an infection worse, Jenkins said.

Findings presented September 7 at the annual meeting of the Society for General Microbiology in Edinburgh, Scotland.
 

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