Posted on behalf of Kate Larkin
A study published today in Nature sheds new light on two key toxins in the diarrhoea-causing bacterium Clostridium difficile and their role in infection. Researchers led by Nigel Minton, a microbiologist at the University of Nottingham, UK, produced the first double-mutant strain of C. difficile, de-activating the toxin genes to understand the importance of each one in turn.
“C.difficile is very difficult to manipulate and has only been achieved since 2007,” says Sarah Kuehne, microbiologist at the University of Nottingham and lead author of the study, speaking at the British Science Festival today. “We found that, unlike a previous study, both toxins play a crucial role in infection” says Kuehne.
This renews a debate on C. difficile toxins which has spanned the past three decades. Only last year another study published in Nature claimed that toxin A alone did not cause infection and it was only toxin B that caused pathogenesis.
“The study last year was a shocking result at the time” says Stephen Cartman, microbiologist at the University of Nottingham and co-author of the latest study. “At the time we were also working on a parallel study and were finding different results. So we had to make sure we were confident of our results before we published. Our results align much better with work done before in the 1980’s and 1990’s and this is much more what people were expecting,” says Cartman.
C. difficile is found in hospitals in Western Europe and North America because it is antibiotic resistant and typically spreads after a patient has knocked out their normal bacterial gut flora whilst taking antibiotics. But whilst most infections lead to diarrhoea, some are much more serious, leading to pseudomembranous colitis, which can be deadly.
“C. difficile is a serious infection which in 2009 led to five times more deaths than MRSA across England and Wales,” says Cartman. Pinning down the toxins it excretes is crucial to developing better treatments. “We are working towards vaccine development programmes but we first need to better understand the diagnostic strategies,” says Cartman.