Hospitals currently cannot tell whether two patients carrying the same MRSA strain caught it from each other or from separate sources. The bacterium *Staphylococcus aureus* lives harmlessly on many people but can cause severe infections in hospital patients, and the drug-resistant MRSA form spreads easily between patients. Two dominant MRSA strains, EMRSA-15 and EMRSA-16, are so genetically similar that standard typing tools cannot distinguish between a direct transmission and independent acquisition. This blind spot means infection control teams cannot pinpoint where their prevention strategies are failing. The researchers will sequence the full genomes of hundreds of MRSA samples collected across the UK, searching for single-letter DNA changes that reliably mark transmission clusters. They will then develop a new generation of typing tools based on these genetic differences and translate them into clinical use. If successful, hospitals will gain the ability to map MRSA transmission pathways in real time, revealing exactly where and how the bacteria move between patients. This could strengthen infection control measures, reduce MRSA outbreaks, and lower the number of hospital-acquired infections—a quiet but critical improvement to patient safety that most people never think about until they or a family member are admitted.
View original technical description
A bacterium called Staphylococcus aureus is often part of our normal body flora and is harmless for the majority of people, but may sometimes cause infection that ranges in severity from trivial (e.g. boils) to severe (e.g. infection of the heart valves or bones). Staphylococcus aureus is also the leading cause of infections that occur in people after admission to hospital for reasons other than infection. Some strains of Staphylococcus aureus have acquired resistance to an antibiotic (methicillin) that is otherwise the treatment of choice for infection caused by this organism. These methicillin-resistant Staphylococcus aureus (MRSA) are most often found in the hospital setting. Becoming a carrier of MRSA is the forerunner to infection, and development of carriage in a given patient occurs after transmission of the organism from another patient. Hospital infection control aims to prevent spread of these bacteria but can sometimes fail. One way to reveal how bacteria spread and pinpoint where preventive strategies require strengthening is to perform bacterial typing to determine if MRSA affecting two patients are highly related (suggesting that it passed from one person to another) or different. However, this is not straightforward since two particular strains of MRSA have become so successful that they are almost always the culprits (they are called EMRSA-15 and EMRSA-16). Two patients carrying or infected with one of these strains could have acquired it from each other or may have acquired it independently of each other, and current laboratory typing tools are unable to tell the two situations apart. We believe that it is now possible to develop a new generation of typing tools that distinguish between two strains based on the identification of single letter DNA changes in the bacterial genome. The objective of our study is to focus on MRSA strains that are important in the UK. We will undertake whole genome sequencing of numerous isolates each of EMRSA-15 and -16 obtained from across the country. The data generated will be examined to define those genetic differences that would prove most useful for defining clusters within the group. This will form the basis for the development of a new generation of typing technique that we aim to translate into the clinical setting where it will provide the capability to study the spread of MRSA transmission in the UK and beyond in such a way that has previously proved impossible.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know