Antimicrobial resistance in the UK and Ireland.

After the dramatic expansion of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella in the UK and Ireland from 2001 onwards, the situation appears to have stabilized, with similar ESBL prevalence detected in 2007 as in 2006. Equally dramatic, but more welcome, is the sharp reduction since 2005 in the number of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemias in England, and the reduction in prevalence of MRSA as a proportion of all S. aureus bacteraemias. These two trends dominate the information from the major resistance surveillance schemes in the UK and Ireland, but a wealth of further detail is available from these rich information sources. Resistance rates vary between hospitals, between specialities within hospitals and between patients within specialities depending on their characteristics such as age. In addition, resistance varies over time as new genetic mechanisms appear in clinically relevant bacteria, and spread or retreat under the pressures of competition and changing patterns of antibiotic use. Up-to-date information is required, not only at a national level for research and policy purposes, but at a very local level to inform day-to-day clinical decisions.