Objectives: To determine the prevalence of pressure sores, their risk factors, and the responsible microbial agents in an acute-care hospital and to evaluate their management., Method: A prevalence survey was conducted from 5 July through 9 July 2004. Investigators completed a standardized questionnaire for each hospitalized patient, including demographic data (age, sex, previous hospitalizations, etc.) and Braden scale risk factors (sensory perception, humidity, activity, mobility, nutrition, and friction and shear). Two experts in skin care detected pressure sores by physical examination of the patients. Each pressure sore was swabbed and inoculated on selective media. Management was evaluated by reviewing the clinical charts of each patient with a pressure sore., Results: The study included 535 adult patients (aged 59 +/- 19 years): 75 ulcer sores were observed in 37 patients (prevalence=6.9%). Stage I sores accounted for 24% of the total, stage II for 29%, stage III 31%, and stage IV 16%. The most frequent site was the heel (41%), followed by the sacrum (20%), elbow (11%), back (7%) and ischial tuberosities (7%). Sixty (80%) were acquired while hospitalized. Age-adjusted multivariate analyses found that the risk factors significantly associated with pressure sores were Braden score< or =15 (OR=5.9, 95% CI: 2.4-13.7, p<0.0001) and previous pressure sores (OR=5.0 95% CI: 2.2-11.6, p<0.0001). Eleven sores (24.5%), mostly stage III and IV, were colonized by multiple-drug-resistant bacteria (i.e., methicillin resistant Staphylococcus aureus, extended spectrum beta-lactamase Enterobacteriaceae). Seven (9.3%) of the 75 ulcers were diagnosed only during the survey, by the experts; of the 68 diagnosed before the survey, 57 (83.8%) had been under treatment. Treatment was considered inappropriate according to French guidelines in 31.6% of the cases., Conclusion: This prospective prevalence study resulted in better awareness of the patients at risk for pressure sores. It also made the recently created mobile geriatrics unit better known within the hospital.