(The analysis will not affect how individual patients are treated, because all variants of MRSA are treated the same. Tests that classify subtypes of the bacteria are used to track the spread of infection, rather than to make treatment decisions.)
It’s not yet clear how the technology might be incorporated into standard public health efforts to track and control MRSA infections. “I believe this approach will expand our understanding of the evolution of MRSA, but I don’t think it will catch on right now in hospitals,” says Dan Diekema, a physician and epidemiologist at the University of Iowa, who was not involved in the study. “I think most hospitals find our current typing methods to be adequate in helping to guide prevention efforts. It’s not exactly clear to me how having a finer-grained look would impact prevention efforts.”
Peacock aims to address that question with ongoing studies. “We hope to clearly define through prospective studies of this tool what its value is and how to incorporate it into a hospital setting,” she said. The technology would need to undergo some major changes to transform from research tool to standard surveillance measure. “Before being adopted in standard clinical practice, the technology needs to be adapted so that it can be used in any major laboratory,” said Peacock. “We want the readout not in terms of sequencing but in what potential virulence it carries, and what its origins might be.”
Currently, sequencing a MRSA genome takes four to six weeks and costs about $300. “Even though turnaround time has been dramatically reduced from years to weeks, it’s still not a practical timescale for use in clinical settings,” said Stephen Bentley, senior author on the study. “But I expect that with third-generation sequencing technology, the turnaround time could be reduced to hours and the per sample cost might be reduced to the £20 mark [about $30].”
The project is part of a growing trend that capitalizes on increasingly affordable sequencing technologies to track the origins, evolution, and migration of human pathogens. “It’s going to require scientists to do some real innovative thinking to fully explore the potential of this technology,” said Bentley. Researchers at the Sanger Institute have already applied it to a number of other infectious organisms, including those responsible for tuberculosis, pneumonia, and meningitis.