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RESEARCHERS at the Université de Saint-Boniface, Canada, say that their non-toxic disinfectant, ‘Akwaton’, can kill bacterial spores which are difficult to destroy and are responsible for persistent hospital infections.

Clostridium difficile, a so-called ‘hospital superbug’, causes diarrhoea and occasionally severe bowel inflammation in patients with weakened immune systems, and can be very hard to treat. It forms spores in adverse conditions, which can survive for several years in a dehydrated state, and are very difficult to kill with conventional disinfectants. Mathias Oulé, a microbiology professor at Saint-Boniface, says that Akwaton (polyhexamethylene guanidine hydrochloride) could solve the problem at very low concentrations.

The disinfectant has already been proven against Methicillin-resistant Staphylococcus aureus (MRSA) and E. coli cells, and works by attacking and tearing the bacterial cell wall and membrane. Oulé and his team tested Akwaton on spores of Bacillus subtilis (which is similar to C. Difficile), on stainless steel/glass surfaces, and in suspension in water. The spores in suspension were destroyed after just 90 s, with an Akwaton concentration of just 0.44%, while a concentration of 0.52% was required to kill spores on surfaces in the same time period. Concentrations of less than 0.1% were also effective if left for longer periods of time.

“Most disinfectants have to be applied at much higher concentrations – typically between 4–10% – to properly get rid of bacterial spores. Unfortunately such high levels of these compounds may also be harmful to humans and other animals. Akwaton is non-corrosive, non-irritable, odourless and is effective at very low concentrations,” says Oulé.

He tells tce that he and his team are now investigating the disinfectant’s use as a fungicide. They believe it could be used in cosmetic products, in water treatment, topical skin disinfectants and for crop protection.