%P ?- ? %O PMCID: PMC3409138 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 3.0) license. Authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, and/or copy articles in PLOS journals, so long as the original authors and source are cited. %V 9 %X Changing clinical impact, as virulent clones replace less virulent ones, is a feature of many pathogenic bacterial species and can be difficult to detect. Consequently, innovative techniques monitoring infection severity are of potential clinical value. %D 2012 %N 7 %L discovery1417043 %A I Schlackow %A AS Walker %A K Dingle %A D Griffiths %A S Oakley %A J Finney %A A Vaughan %A MJ Gill %A DW Crook %A TE Peto %A DH Wyllie %K Aged, Aged, 80 and over, Clostridium Infections, Clostridium difficile, Computer Simulation, Demography, Female, Great Britain, Humans, Incidence, Laboratories, Hospital, Male, Models, Biological, Neutrophils, Population Surveillance, Registries, Regression Analysis, Reproducibility of Results, Retrospective Studies, Severity of Illness Index, Virulence %C United States %T Surveillance of infection severity: a registry study of laboratory diagnosed Clostridium difficile %J PLoS Med