25 Ago Clostridium difficile infection underdiagnosis in Italy: do we know the true magnitude of the problem? A prospective cohort study

C. difficile (CD) is the main cause of nosocomial infectious diarrhea. CD infection (CDI) underdiagnosis contributes to increase CD spread within the hospital setting. The aim of our study is to assess the rate of CDI underdiagnosis, either community- or hospital-acquired, in patients with diarrhea in an acute care hospital. From November 2015 to July 2017, all adult patients presenting with diarrhea in our 200-bed acute care hospital were prospectively enrolled in the study. Charts were reviewed for assessing stool testing requested by the clinicians. GDH plus toxins assay, PCR for CD were performed on each collected stool samples whether or not treating physicians requested them. During the study period, 5.169 patients were admitted in our hospital, 384 (7.4%) of them had diarrhea. 202 (59.4%) patients presented diarrhea at hospital admission and 138 (40.6%) ≥48 hours from admission. In the community-onset group, 113/202 (55%) and 89/202 (45%) presented with community- (CA) and healthcare-associated (HCA) diarrhea, respectively. 54 community-onset group patients were diagnosed with CDI: 13/54 (24%) were CA and 41/54 (76%) HCA. In the nosocomial onset group 20/138 (14.4%) samples were CD positive. Overall, of the 72/340 (21.1%) stool samples for which CD testing was not requested, laboratory was able to detect CDI in 4 cases, 3 of them in the CA group. In our study, CDI underdiagnosis was not negligible. In CA-diarrheas, 2,7 CDI cases per 100 patients would have been missed.