Association of healthcare exposure with acquisition of different Clostridium difficile strain types in patients with recurrent infection or colonization after clinical resolution of initial infection

Background: Following the resolution of an episode of Clostridium difficile infection (CDI), the factors associated with acquisition of different C. difficile strain types in patients with recurrent infection or persistent colonization have not been evaluated. Aim: To explore factors with potential correlation with acquisition of different C. difficile strain types in patients clinically cured of CDI through long-term follow-up across the continuum of care. Methods: Polymerase chain reaction ribotyping was performed on C. difficile isolates recovered at baseline and follow-up (days 19-38) from stool samples of patients successfully treated for CDI, and those who had recurrence and/or colonization following symptom resolution. Chart review was conducted to determine factors associated with acquisition of a different C. difficile ribotype. Findings: Of 25 patients initially cured of CDI, five had a recurrence and eight were colonized at follow-up. Patients did not differ with regard to age, sex, and whether the initial infection was with the BI/NAP1/027 strain. Ribotyping revealed that two out of five patients had recurrence attributed to a different strain type. Three of the colonized patients demonstrated strain switching compared with five patients who carried the same baseline strain. All patients (both infected and colonized) with different C. difficile ribotypes were exposed to the healthcare system. Exposure to antibiotics and proton pump inhibitors were not related to strain switching. Conclusion: Exposure to healthcare, but not to antibiotics or proton pump inhibitors, was consistently associated with recurrence or colonization with a different C. difficile ribotype.