1. Introduction There are few public health issues of greater importance than antimicrobial resistance in terms of impact on society. This problem is not restricted to the UK. It concerns the entire world and requires action at local, national and global level 1. This poster discusses the link between the time taken to develop antibiotic resistance in relation to antibiotic usage in an oncology setting. Background The emergence of strains of glycopeptide resistant enterococci (GRE) are problematic since they pose challenges for treatment; and in immunocompromised patients, may lead to greater morbidity and mortality. Exposure to a number of different antibiotics can promote the development of resistance 2. Following an observed increase in the isolation of GRE over a period of time at the Christie Hospital the use of a range of antibiotics was examined. Methods Pharmacy records of issues of five antibiotics (linezolid, vancomycin, teicoplanin, meropenem and piperacillin/tazobactam) were examined for the two year period April 2011 to March 2013. The raw data was recalculated using WHO defined daily doses (DDD) to allow comparison of different dosage forms 3. Emergence of antibiotic resistance in a real life setting Duncan Saunders 1, Geoff Saunders 2 1. University of Glasgow, 2. The Christie NHS Foundation Trust Results and discussion Over the two years antibiotic use was broadly the same with peaks in August, October, February and March in 2011/2012 and September, December, January and March in 2012/2013. In both years the most used antibiotic was meropenem, and the least used linezolid. During 2012/13 peak numbers of GRE cases were seen in April, July, December and March. There was a strong correlation (0.65 -0.62) between monthly issues of antibiotics (February-January) and GRE cases (April-March). This suggests the increase of GREs is related to the use of antibiotics 2-3 months before. Comparing use individually against the number of observed GREs, Teicoplanin shows a strong correlation (0.68) for the period of March 2012 to February 2013. Meropenem and Piperacillin/Tazobactam both show a strong correlation 2-3 months before, Meropenem 0.64 at 3 months, Piperacillin/Tazobactam 0.72 at 2 months and 0.58 at 3 months. This difference in the timing of the associated GREs suggests a difference in the formation of the resistant colonies. The Glycopeptide, teicoplanin, has the shortest time line, it being correlated to GRE infection one month after the use of the drug. The broad spectrum antibiotics, Meropenem and Piperacillin/Tazobactam, have a longer period of time between the administration of the drug and the correlated GRE infection, 3 months and 2 months respectively. This suggests a difference in the way that the GRE colonies form following the use of these antibiotics. Understandably the GRE infection following treatment with a glycopeptide comes much quicker, suggesting that the GRE colonies that survive are selectively resistant to the antibiotic and are able to colonise and regrow unopposed. In the use of broad spectrum antibiotics the mechanism in play seems to take a longer period of time. This may be due to a number of factors, yet to be determined. Whilst the clinical significance of these findings on the treatment of individual patients is as yet unknown, this audit reinforces the need for good prescribing practice, ensuring prudent use of antibiotics to keep development of resistant clones to a minimum. Although the use of broad spectrum and glycopeptide antibiotics cannot be avoided in the management of this group of patients; oncology pharmacists should be aware of the timeline between increased use of these agents and the emergence of resistant strains. Patient care is improved through heightened awareness of increased prevalence of GRE. Future work could compare antibiotic usage and resistance patterns with other similar trusts. References UK Five Year Antimicrobial Resistance Strategy 2013 to 2018. Department of Health. London 2013 1. HPA – Antibiotic resistance. http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/A ntibioticAwareness/ Accessed on 10/07/2013 Last Updated 13/02/2013 http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/A ntibioticAwareness/ 2. WHOCC – Definition and general considerations. http://www.whocc.no/ddd/definition_and_general_considera/ Accessed on 10/07/13 Last Updated 17/12/2009 http://www.whocc.no/ddd/definition_and_general_considera/