Skin secretion could battle TB, lethal bugs

Our skin secretes an antibiotic called dermcidin, which could act as a potent weapon against tuberculosis (TB) and dangerous bugs, says a study.

A team of researchers from the universities of Edinburgh, Goettingen, Tuebingen and Strasbourg have uncovered the compound's atomic structure, helping them pinpoint for the first time what makes dermcidin such a powerful weapon against lethal pathogens.

Although about 1,700 types of these natural antibiotics are known to exist, until now scientists did not have a detailed understanding of how they work, the journal Proceedings of the National Academy of Sciences reports.

Ulrich Zachariae from Edinburgh's School of Physics, who co-authored the study, said: "Antibiotics are not only available on prescription. Our own bodies produce efficient  substances to fend off bacteria, fungi and viruses."

"Now that we know in detail how these natural antibiotics work, we can use this to help develop infection-fighting drugs that are more effective than conventional antibiotics," Zachariae added, according to an Edinburgh statement.

Sweat spreads highly efficient antibiotics on to our skin, protecting us from dangerous bugs. If our skin gets injured by a small cut, a scratch, or the sting of a mosquito, antibiotic agents secreted in sweat glands, such as dermcidin, rapidly and efficiently kill invaders.

These natural substances, known as antimicrobial peptides (AMPs), are more effective in the long term than traditional antibiotics because germs are not capable of quickly developing resistance against them.

The antimicrobials can attack the bugs' Achilles' heel - their cell wall, which cannot be modified quickly to resist attack. Because of this, AMPs have great potential to form a new generation of antibiotics.

Scientists knew for some time that dermcidin is activated in salty and slightly acidic sweat. The molecule then forms tiny channels perforating the cell membrane of bugs, which are stabilised by charged particles of zinc present in sweat.

As a consequence, water and charged particles flow uncontrollably across the membrane, eventually killing the harmful microbes.

The compound is active against many well-known pathogens such as TB, Mycobacterium tuberculosis, or Staphylococcus aureus. Multi-resistant strains of Staphylococcus aureus, in particular, have become an increasing threat for hospital patients.