Warning over contaminated food link to C. diff superbug

Warning over contaminated food link to C. diff superbug
Warning over contaminated food link to C. diff superbug

The notorious hospital super bug C. diff could be spread through contaminated food, a new study warned.

The bug Clostridium difficile, known as C. difficile or C. diff, which causes stomach upsets and diarrhoea, could come from contaminated food and may be a more widespread problem than previously thought.

Now University of Oxford said people may need to be vaccinated against it and the spreading of manure onto farmland reviewed.

The bug is present as one of the ‘normal’ bacteria in the gut in up to three per cent of healthy adults.

It most commonly affects people who have recently been treated with antibiotics because theses disturb the balance of ‘friendly’ bacteria in the gut.

The antibiotic resistant bug can spread easily to patients on wards, in care homes or those with weakened immune systems, with the elderly most at risk.

Common symptoms are watery diarrhoea, which can be bloody, painful tummy cramps, feeling sick, dehydration, a fever and loss of appetite and weight.

The new research used DNA fingerprinting to examine which particular types of the bacteria were causing infections in patients and how widely they are distributed in Europe.

Some strains were found clustered within a particular country, suggesting they were possibly being passed around within hospitals - a well-recognised route of transmission.

However, because some other strains were found dispersed in several different countries, this adds weight to the idea that C. difficile could also be transmitted via our food.

Clinical lecturer Dr David Eyre said: “We know that C. difficile lives in the gut in a small proportion of healthy people, where it causes no symptoms.

“However, its resistance to antibiotics means it can grow uncontrollably in patients treated with the drugs, causing diarrhoea that can be severe or even fatal.

“It is the most frequent cause of infectious diarrhoea in hospitalised patients, and the increase in the use of antibiotics has allowed C. difficile to spread more effectively.

“Lots of effort has gone into controlling its spread including infection control interventions such as hand washing campaigns, and reducing the use of antibiotics that can lead to infection.

“Despite these measures, people are still getting C. difficile infections and the routes of transmission are not completely understood.”

He noted possible explanations for its spread include asymptomatic patients, children who carry C. diff more commonly than adults, and farm and domestic animals.

The new research included all the stool samples submitted on one day in summer and one day in winter in 2012/2013 from 482 European hospitals.

The researchers then selected the ten most common types of C. diff found in the samples.

In each case, they used DNA fingerprinting to examine how widespread the type was within countries and between countries.

Dr Eyre added: “We know that C. difficile infection can spread within hospitals.

“If this was the only route of transmission, we would expect to see each type of the bacteria concentrated within one area.

“However, because we also saw some types that were spread around several countries, this suggests the bacteria are moving around by other means.”

Five of the types were clustered within countries while five others were not.

One type was found in Bulgaria, the Czech Republic, Finland, France, Germany, Hungary, Italy, The Netherlands, Poland, Romania, Slovakia, Spain, Sweden and the UK.

Another type which was spread around Austria, France, Germany, Greece, Ireland, Italy, Portugal, Spain and UK has previously been associated with pig farming.

Dr Eyre continued: “We don’t know much about how C. difficile might be spread in the food chain, but this research suggests it may be very widespread.

“If that turns out to be the case, then we need to focus on some new preventative strategies such as vaccination in humans once this is possible, or we might need to look at our use of animal fertilisers on crops.

“This study doesn’t give us any definitive answers, but it does suggest other factors are at play in the spread of C. difficile and more research is urgently needed to pin them down.”

To investigate further, Dr Eyre hopes to repeat the study and obtain samples from food, the wider environment and hospitals, to better understand where the source of infection might be.

The research was presented at the 27th European Congress of Clinical Microbiology and Infectious Diseases.