Only one in five 'hospital superbug' cases caught in hospital, sequencing study reveals

DNA sequencing of Clostridium difficile (C. diff) samples
reveals that the dangerous bacteria, which was previously predominantly
transmitted in hospital, is now mostly being caught outside.

Researchers sequencing the complete genome of C. diff found
only 19 percent of infections were spread within hospitals. Contact with
infected people in the community as well as animals and food now account for
the majority of new infections, the scientists say.

'We must be clear, good infection control measures have
helped minimise transmission rates in hospitals', Professor Tim Peto from
the University of Oxford, UK, a study co-author, said.

'However, what our study has shown is the vast majority of
cases were not caught from other hospital cases and the total number of cases
has fallen, so other factors, in addition to hospital infection control, must
be at work'.

By analysing 1,223 stool samples infected with the gut bug,
researchers could look for genetic similarities between cases. The team tracked
likely sources of transmission by combining the genetic data with hospital records
and community movements.

The study examined all cases of C. diff infection in the four
Oxford University Hospitals between September 2007 and March 2011. The study
period coincided with a government programme to 'deep-clean' UK hospitals. The
deep-clean campaign aimed to reduce infections by 'superbugs' including C. diff
and methicillin-resistant Staphylococcus aureus (MRSA).

During this time the use of antibiotics fell across 175
English hospitals. Overuse of antibiotics is associated with the superbugs'
emergence.

Dr David Eyre, from the Nuffield Department of Clinical
Medicine at the University of Oxford and co-author of the study, said: 'People
usually become ill with C. diff after taking antibiotics, because antibiotics
don't just kill "bad" bugs but also "good" bugs in the gut,
allowing the resistant C. diff to take over'.

C. diff causes severe diarrhoea, abdominal cramps and,
sometimes, inflammation of the colon. Infection can be deadly, especially for
elderly people.

'Obviously hospital infection control measures have had a
big impact on C. diff cases', Professor Nigel Minton from the Clostridia
Research Group at the University of Nottingham, who was not involved in the
study, told BBC News.

'But
there is a growing feeling that community-acquired C. diff is equally important
and there are also studies suggesting possible transmission to humans from
animals. This has quite clearly been demonstrated from pigs to humans in the
Netherlands. Nursing homes are a major factor as well: it is where you get a
lot of people susceptible to infection'.