Aggressive infections in hospitals are an increasing health problem worldwide. The development of bacterial¹ resistance is alarming. Now a young Danish scientist has found a natural substance in a Chilean rainforest plant that effectively supports the effect of traditional treatment with antibiotics³. PhD Jes Gitz Holler from the University of Copenhagen discovered in a research project a compound that targets a particular resistance mechanism⁴ in yellow staphylococci（葡萄状球菌） . The development of resistance in these specific bacteria is extremely rapid. Bacterial strains that do not respond to treatment have already been found in the USA and Greece.

"I have discovered a natural substance in a Chilean avocado（鳄梨） plant that is active in combination treatment with traditional antibiotics. Resistant⁵ bacteria have an efflux（流出，消逝） pump in their bacterial membrane⁶ that efficiently⁷ pumps out antibiotics as soon as they have gained access. The identified natural substance inhibits⁸ the pumping action, so that the bacteria's defence mechanisms⁹ are broken down and the antibiotic² treatment allowed to work," explains Jes Gitz Holler.

Jes Gitz Holler gathered specimens¹⁰ of the plant, which comes from the Persea family, in Chile, where the Mapuche people use the leaves of the avocado plant to heal wounds. The results have been published in Journal of Antimicrobial Chemotherapy.

The so-called MIC value is the lowest possible concentration of an antibiotic that inhibits the bacterial growth. With his compound from the medicine chest of the Mapuche people, Jes Gitz Holler can lower the MIC value by at least eight times:

"The natural compound has great potential and perhaps in the longer term can be developed into an effective drug to combat resistant staphylococci. At this time there are no products on the market that target this same efflux-inhibitor mechanism. We want to improve the active substance using synthetic¹¹ chemistry in the laboratory. That will also ensure sustainable production of a potential drug while protecting rainforest plants," continues Jes Gitz Holler.

Jes Gitz Holler emphasises that a commercial product will benefit the Mapuche people. At present there is a written agreement between the Faculty¹² of Health and Medical Sciences and the representative of the Mapuche people, Alfonso Guzmán, PhD, who helped procure¹³（获得） the plant material.