Cold plasma has received a further boost as a potential alternative to antibiotics in the fight against multi-drug resistant bacteria. A study published by a Russian-German research team found that just ten minutes of treatment with a low temperature (35-40°C/95-104°F) plasma torch killed drug-resistant bacteria in wound infections in rats and also increased the rate at which wounds healed.

Plasmas, the fourth type of matter after solids, liquids and gases, are formed when atoms are stripped of their electrons, producing ionized gas flows. Hot plasmas are already used to disinfect surgical instruments, however cold plasmas are a more recent development.

Gizmag previously reported on two cold plasma prototypes, one of which is designed to disinfect skin and the other to disinfect wounds.

The recent study, from the Gamaleya Institute of Epidemiology and Microbiology in Moscow, tested plasma against bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus, common causes of chronic wound infections that resist antibiotics because they can grow together in protective layers called biofilms.

The plasma torch killed up to 99% of bacteria in laboratory-grown biofilms after five minutes, and about 90 % of the bacteria (on average) infecting skin wounds in rats after ten minutes.

Research leader Dr Svetlana Ermolaeva said "Cold plasmas are able to kill bacteria by damaging microbial DNA and surface structures without being harmful to human tissues. Importantly we have shown that plasma is able to kill bacteria growing in biofilms in wounds, although thicker biofilms show some resistance to treatment."

"Another huge advantage to plasma therapy is that it is non-specific, meaning it is much harder for bacteria to develop resistance. It's a method that is contact free, painless and does not contribute to chemical contamination of the environment."

Drug-resistant bacteria are a growing problem worldwide. Other potential solutions include secretions from frog skins, and narrow spectrum lighting.