Stopping superbugs in their tracks

Hundreds of millions of patients around the world are affected by healthcare-associated infections each year, although the true scale of their global burden and impact on health remains unknown because of the difficulty in gathering reliable data. In developing countries, the problem of such infections is compounded by the fact that the pathogens involved are frequently resistant to the antibiotics available.

Reducing mortality and morbidity from healthcare-associated infections depends on effective prescribing policies based on information provided by diagnostic microbiology, as well as prevention through improved hygiene such as frequent hand washing. ‘One of the major difficulties in resource-poor countries,’ says Professor Sharon Peacock, from the Departments of Medicine and Pathology, ‘is the lack of even simple diagnostic microbiology in many hospitals. As a result, many pathogens go unrecognised.’

Having spent most of the past decade working in resource-restricted areas of south-east Asia, Professor Peacock believes that researchers can help tackle this problem using technology at two ends of the spectrum. ‘By supporting the development of low-cost, sustainable diagnostic microbiology laboratories to identify pathogens, information is generated to guide prescribing and highlight the need for infection control. This also provides bacterial strain collections that can then be examined using cutting-edge tools to define transmission pathways of important pathogens at local, national and global levels.’

Detective work

The antibiotic-resistant MRSA ‘superbug’ has a deservedly high profile across the developed world but is barely on the radar in developing countries. For example, until recently, there had been no documented report of MRSA in Cambodia. This isn’t because the country has remained completely free of the pathogen but simply because there were no facilities to detect its presence. Now, the Angkor Hospital for Children in Western Cambodia has such a laboratory, the development of which was supported by a team led by Professor Peacock while working at the Wellcome Trust-Mahidol University-Oxford Tropical Medicine Research Unit in Thailand, where she continues to support research following her move to Cambridge in 2009.

Within a month of opening, the first child with MRSA infection was identified. And, with continued support from Cambridge- and Thailand-based researchers, the laboratory has recently reported that MRSA causes infection in both the hospital and the community, and is being carried by a proportion of the population.

The impact of detecting these and other multi-resistant pathogens is potentially huge, explains Professor Peacock: ‘Such information alerts healthcarers and policy makers of the possibility of infection with these organisms and the risk of treatment failure using the readily available antimicrobial drugs, as well as supporting the need for hand washing to reduce spread among hospital patients’.

Tracking the global spread of multi-resistant pathogens

As highlighted by a study published this year in Science magazine, cutting-edge technology also has an important role to play. In this study, Professor Peacock was part of a team led by the Wellcome Trust Sanger Institute at Hinxton, Cambridge, which developed high-throughput genome sequencing to study the transmission of a single clone of MRSA that has become disseminated across much of the world.

Existing techniques were unable to discriminate between individual strains, but genome sequencing showed that no two strains were genetically identical. The beauty of the technique is that it allows healthcare officials to see how MRSA, or any other pathogen, can evolve and spread – from person to person, from hospital to hospital, and from country to country.

Professor Peacock’s research is continuing to use this sophisticated technology to inform better infection control of MRSA, and other pathogens, in hospital settings. ‘Being able to feed this information back to hospitals,’ she explains, ‘is key for interventions to be targeted with precision and according to need.’

For more information, please contact Professor Sharon Peacock (sjp97@cam.ac.uk) at the Departments of Medicine and Pathology. Professor Peacock chairs the Cambridge Infectious Disease Initiative, one aim of which is the development and translation of research in developing countries.