D or colonized with ESBL-E were significantly higher in phase 2 than phase 1 (3 versus 12.3 , p < 0.05). However, the AUD values for fluoroquinolones (6.8 versus 10.4 defined daily doses/1,000 bed-days, p = 0.27), third-generation cephalosporins (19.9 versus 33.3 defined daily doses/1000 bed-days, p = 0.36), tazobactam/ piperacillin (48 versus 50.7 defined daily doses/1000 bed-days, p = 0.55), and carbapenems (27.3 versus 60.3 defined daily doses/1,000 bed-days, p = 0.06) were not significantly different in each subphase. Moreover ICU mortality (17.9 versus 16.1 , p = 0.3) was also not found to differ significantly in the different phases of the study. Conclusions: The findings of this study suggest that the performance of routine stool cultures for ESBL-E in ICU patients had no effectiveness for improving the AUD values and clinical outcome.Reference 1. Mark E. Rupp and Paul D. Fey: Extended Spectrum ?Lactamase (ESBL)Producing Enterobacteriaceae Considerations for Diagnosis, Prevention and Boceprevir Drug Treatment Drugs 2003; 63 (4): 353-antibiotic guidelines, developing robust local guidelines based on the microbiological data on antibiotic sensitivity of PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/22993420 the organisms to guide prophylaxis will be helpful in achieving high rates of clinical cure.Reference 1. Ranjini et al. Community Acquired Infection 2015;2:19-24.P074 Prevalence, risk factors and outcomes of methicillin-resistant staphylococcus aureus nasal colonization in critically ill patients H. Al-Dorzi, M. Almutairi, B. Alhamadi, A. Crizaldo Toledo, R. Khan, B. Al Raiy, Y. Arabi King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia Critical Care 2016, 20(Suppl 2):P074 Introduction: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing in the general population. In this study, we examined the prevalence of MRSA nasal colonization in patients admitted to the intensive care unit (ICU), its risk factors and the association with morbidity and mortality. Methods: This was a retrospective cohort study of all patients who were admitted to the ICU of a tertiary-care hospital in Riyadh, Saudi Arabia in 2011, had nasal swab for MRSA colonization on admission and stayed in the ICU for >48 hours. We calculated the PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/3021955 MRSA colonization prevalence and studied the association between MRSA colonization status and patient characteristics and outcomes, including infections due to MRSA and mortality. Results: The cohort included 464 patients with the following characteristics: age = 51.7 ?21.9 years, APACHE II score = 23.3 ?8.7, 65.9 males and mostly admitted from the emergency department (40.7 ) and wards (30.2 ). Thirty-one (6.7 ) patients were MRSA colonized and had similar age, gender distribution, chronic comorbidities and admission APACHE II score compared with the other patients. Patients referred from other hospitals had the highest prevalence (19.4 versus 6.2 for the other patients, p = 0.02). On multivariate analysis with age, gender, APACHE II score and source of admission (other hospitals versus other source) being the independent variables, only admission to the ICU from another hospital was associated with MRSA colonization (odds ratio, 4.01; 95 confidence interval, 1.48-10.90; p = 0.006). Only 3 (0.6 ) patients in the cohort had MRSA bacteremia during ICU stay and all were MRSA colonized (p < 0.001). Furthermore, 14 patients had respiratory tract infection due to MRSA, 9 (64.3 ) of whom were MRSA colonized (p < 0.001).