DNA code of MRSA superbug cracked by scientists
The DNA code of the superbug MRSA has been cracked by scientists so that their future spread can be halted more quickly.A new device can identify specific bacterial strains from their genetic codes so experts can target the transmission path of the infection and cut it off.
In an early test of the technology, researchers halted an outbreak of the MRSA superbug in a special care baby unit at the Rosie Hospital in Cambridge.
It is believed to be the first time DNA sequencing has been used to contain an infectious disease outbreak at a hospital.
The scientists are now developing the concept into a simple system that can be used routinely by hospital staff who are not genetics experts.
In future, it could be used to combat many kinds of infection outbreak, and also help doctors decide the best way of treating patients.
Professor Sharon Peacock, from Cambridge University, who led the research team, told a news briefing in London: ”What we’re working towards is effectively a ‘black box’. Information on the genome sequence goes into the system and is interpreted, and what comes out the other end is a report to the health care worker.
”It could, for example, determine the species of the bacterium; it could determine antibiotic susceptibility, and it could provide information about what genes are present that are often associated with poor outcomes in patients.
”It will give information about how related that organism is to other organisms within the same setting, giving an indication of the capability of transmission from one patient to another.”
A report on how the baby unit outbreak was brought under control appears in the latest issue of the journal The Lancet Infectious Diseases.
The scientists used a technique called rapid whole genome sequencing, which maps an organism’s entire genetic code, to analyse MRSA bacteria taken from 12 babies.
MRSA (methicillin resistant Staphylococcus aureus) is an antibiotic resistant form of a common skin bug that can cause potentially deadly wound infections in hospitals.
Standard procedures had not been able to show whether a genuine outbreak had occurred, or whether the babies had all coincidentally been exposed to MRSA.
The team was quickly able to confirm that 10 babies were part of an MRSA outbreak involving a previously unknown strain of the bug.
Measures were introduced to clear MRSA from carriers and deep-clean wards, but two months later a new infection case was identified in the baby unit.
DNA sequencing showed it was caused by the same strain identified earlier, carried to the ward by one of 154 screened health care workers.
Co-author Dr Julian Parkhill, head of pathogen genomics at the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, said: ”The staff member was decolonised and went back to work, and we believe this brought the outbreak to a close.”
He said he expected the cost of whole genome sequencing of bacteria to fall from around £100 per sample to £50, and ultimately just ”a few pounds” in the near future.
”People are talking about the thousand dollar human genome,” he added. ”If you can do the human genome for a thousand dollars you can do a bacterial genome for one dollar.”
The MRSA outbreak at the Rosie Hospital, part of Cambridge University Hospitals NHS Foundation Trust, was estimated to have cost the NHS around £10,000. This was double the cost of the DNA sequencing, said the researchers.
Tags: Doctors, Health Direct, Health Professionals, MRSA, NHS Deaths, superbugs