19 November 2012
ByAppeared in BioNews 682
Although it's not the first time this approach has been successful (US researchers achieved a similar outcome with K. pneumoniae back in August, reported in BioNews 670) the study marks important progress in the struggle against a bacterial 'superbug' that plagues hospital wards up and down the country.
When twelve cases of MRSA - methicillin-resistant staphylococcus aureus - were diagnosed among babies at Addenbrooke's Hospital over a six month period, clinicians suspected an outbreak of the infection. Standard diagnosis protocols, however, could not indicate whether the cases were isolated or linked.
A group of researchers from the Wellcome Trust Sanger Institute, the University of Cambridge and Cambridge University Hospitals decided to sequence and analyse the bacterial DNA taken from each of the patients. They found all of the cases to be genetically linked – confirming that particular MRSA strain as a novel outbreak.
The cases were treated and the ward underwent a deep clean, but two months later another case appeared. When researchers sequenced the MRSA's genome, they discovered it to be part of the same outbreak.
Knowing that the source of spread could be within the hospital itself, the team then screened 154 members of staff, and found one to be infected with MRSA. Sequence data confirmed that this case was part of the same outbreak, and the staff member was removed from the ward and treated with antibiotics before returning to work.
'We believe this brought the outbreak to a close', Dr Julian Parkhill from the Sanger Institute told the BBC.
With the cost of whole genome sequencing steadily falling (it has dropped from millions of pounds to around £50 per bacterium) this approach could become standard practice in future, helping to stop outbreaks before they become unmanageable.
'There is a real health and cost burden from hospital outbreaks and significant benefits to be gained from their prevention and swift containment', said Dr Parkhill.
Dr Nick Brown, an infection control doctor within the hospital, welcomed the breakthrough. 'We are always seeking ways to improve our patient care and wanted to explore the role that the latest sequencing technologies could play in the control of infections in hospitals', he said.
'What we have glimpsed through this pioneering study is a future in which new sequencing methods will help us to identify, manage and stop hospital outbreaks, and deliver even better patient care'.