Superbug experts focused on wrong toxin for years

Published on Sunday 1 March 2009 21:04

SCIENTISTS battling the deadly hospital bug Clostridium difficile have spent decades aiming at the wrong target.

A new study shows that researchers have focused on the wrong illness-inducing toxin released by the bacteria.

C diff is a spore-forming bug, first discovered in 1978, which has been sweeping through hospitals around the world.

Normally kept at bay by "good" bacteria in the gut, it can cause severe diarrhoea in patients treated with antibiotics and may be lethal to the very sick or elderly.

The new discovery is reported by Australian and US scientists today in the online version of the journal Nature.

Professor Dale Gerding, from Hines Hospital in Illinois, said: "For 20 years, we have been focusing on Toxin A. But it turns out the real culprit is Toxin B.

"This is a major finding in how C diff causes disease in humans. It completely flips our whole concept of what the important toxin is with this disease."

Scientists in Australia engineered mutant strains of C diff that were tested by Prof Gerding's team.

Co-author Dr Stuart Johnson, from Stritch School of Medicine at Loyola University Chicago,

said: "This is probably the best evidence to date about the relative importance of these two toxins."