Missed diagnosis of Clostridium difficile infection; a prospective evaluation of unselected stool samples

Background: Clostridium difficile infection (CDI) is the leading cause of hospital-acquired diarrhoea in developed countries, however a high proportion of CDI episodes go undiagnosed, either because physicians do not request identification of toxigenic C. difficile or microbiologists do not perform the appropriate tests. Objective: To investigate the clinical characteristics of patients with CDI within a non-selected population and to determine risk factors for clinical underdiagnosis. Methods: We conducted a prospective study in which systematic testing for toxigenic C. difficile on all diarrhoeic stool samples was performed regardless of the clinician's request. Patients aged >2 years positive for toxigenic C. difficile and diarrhoea were enrolled (Jan-June 2013) and monitored at least 2 months after their last episode. Results: We identified 204 cases of CDI, of which three-quarters were healthcare-associated. Most cases were mild to moderate (83.8%), the recurrence rate was 16.2%, and CDI-related mortality was low (2.5%). A significant proportion (12.7%) of CDI cases would have been missed owing to lack of clinical suspicion. Community-acquired cases and young age were risk factors for clinical underdiagnosis. Conclusion: Our data support the introduction of a systematic search for toxigenic C. difficile in all diarrhoeic stools from inpatients and outpatients older than 2 years. (C) 2014 The British Infection Association. Published by Elsevier Ltd. All rights reserved.