Genome sequencing reveals how MRSA spreads

Strains of methicillin-resistant Staphylococcus aureus (MRSA) previously thought to be restricted to hospitals are spreading in the wider UK population, according to new research published in the journal Science (online, 25 October 2017)^[1]
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Researchers tracked the spread of MRSA across one year in the east of England. During that time they analysed MRSA-positive samples from 1,465 people, and, through genome sequencing, found 173 separate clusters of closely related bacteria.

They then used epidemiological data (for example, hospital admissions, and places of residence) to find links between cases.

Their data uncovered two trends. The first was that most cases of MRSA were not confined to single, hospital-based outbreaks but were transmitted by individuals during their daily lives in the wider community. The second was that MRSA strains typically thought to be strictly hospital-associated were spreading in the general community.

However, Sharon Peacock, professor of microbiology at the London School of Hygiene and Tropical Medicine and University College Hospital, and one of the authors of the study, said that this was not a cause for alarm.

“There is no reason to think that MSRA rates are increasing — this research just connected the dots and revealed how MRSA spreads,” she said.

“If we can detect where MRSA transmission is actually going on, we can plan infection control interventions to stop further infections happening”.

Peacock said she was hopeful that, in future, rapid sequencing would allow for immediate infection-control measures to be taken to prevent the spread of MRSA.

“If we can do this sequencing in real time — work out where people are getting MRSA, detect the infections early, and take action — we can minimise future transmission of the infection,” she said.

“These findings will help us to focus resources and take corrective action where most needed.”