Wash helps stop "mad cow" transmission in surgery

British scientists said on Friday they had developed a cheap and effective detergent wash that virtually eliminates the risk of spreading variant Creutzfeldt-Jakob disease, or "mad cow" disease, via surgical instruments.

"It is at least a 100,000-fold reduction in infectivity and possibly more," said Dr Graham Jackson, from the Medical Research Council's prion unit in London.

"I would be disappointed if it is not introduced in hospitals by the end of the year," he added in a telephone interview with APM following publication of his group's findings in the Journal of General Virology.

The development follows concern that patients undergoing routine surgical procedures could be infected with vCJD, and that the rogue prions responsible for the disease could contaminate instruments because conventional sterilization procedures are not effective.

Although single-use surgical instruments were introduced for tonsil operations in the UK in 2001, this policy was later suspended because of concern about higher surgical complication rates.

The MRC team - which also included Professor John Collinge - tested some 400 combinations of enzymes and detergents on prion-contaminated metal wires, which acted as surrogate surgical instruments, and found a combination of two enzymes and one detergent that was highly effective.

"It is not dissimilar from biological washing powder," Jackson said. "It is easy to do and relatively cheap and fits in with existing hospital sterilisation methods."

Unlike some other decontamination techniques that are highly alkaline or acidic, the new technique did not damage surgical instruments or endoscopes.

In their paper, the team writes: "While the three-stage detergent/enzymic procedure we have developed will not ensure absolute sterility of prion-contaminated instruments, its application would be expected to degrade any infectivity risk by several orders of magnitude and very substantially reduce risks of iatrogenic transmission of human prion infection during routine surgery."

Discussions were taking place to find an industrial partner to produce the detergent, Jackson said.

SOURCE: J Gen Virol 2005;86:869-878.