SPECIAL coating kills germs, researcher says

Tuesday, May 22nd 2001, 12:00 am
By: News On 6

WASHINGTON (AP) _ A new polymer coating holds the promise of guarding against infections commonly spread by bacteria lurking on things like telephones and door knobs, researchers say.

``You could coat any type of surface with this material, and it would be there permanently,'' said Joerg Tilleer of the Massachusetts Institute of Technology. ``It is chemically attached so that it cannot be washed away.''

In a study appearing Tuesday in the Proceedings of the National Academy of Sciences, Tiller and his co-authors said laboratory tests show that the coating, called hexyl-PVP, was able to kill up to 99 percent of Staphylococcus, Pseudomonas and E. coli, all common disease-causing organisms.

Tiller said the coating, applied to glass slides, was tested by spraying the slides with a concentrated solution of the bacteria groups common in household and hospital infections. The results were compared to uncoated glass slides that also were exposed to the bacteria solution.

``The test solution was rather like what happens when you sneeze or cough,'' said Tiller. On the glass slides treated with hexyl-PVP, 94 percent to 99 percent of the Staphylococcus organisms were killed. For Pseudomonas and E. coli, the kill rate was consistently at 99 percent.

Tiller said the polymer kills bacteria by a powerful chemical-electrical action.

``It is a polymer with permanent positive charge,'' said Tiller. ``This positive charge destroys the bacteria cell walls and membranes.''

Tiller said the kill mechanism probably would not allow bacteria to develop a resistance, as can happen with antibiotics, he said.

``It is a chemical kill,'' he said. ``For them to develop resistance, the bacteria would have to change their whole composition, and I don't think this can be done.''

He said the anti-bacterial coating could be incorporated into the manufacturing process so the surface of many products could be permanently sterile.

Surfaces still would require periodic washing to remove dead bacteria that float out of the air and land on the killing surface.

Tiller and his co-authors hold a patent on the chemical coating but are not involved in any effort to bring the germ-killing technology to the market, he said.