Comparison of Clinical Features Between Inpatient and Outpatient Cases of Clostridium difficile Infection

Abstract

The Microbiology Laboratories at Harborview Medical Center and the University of Washington Medical Center evaluated the Biofire FilmArray Gastrointestinal Panel, a multiplex PCR assay to conventional stool culture. The FilmArray can detect both toxin A (tcdA) and toxin B genes (tcdB) in Clostridium difficile. C. difficile is not detected by conventional stool culture. Instead, both laboratories use the Cepheid GeneXpert C. diffcile assay to rapidly detect the toxin B gene (tcdB). These two different test methods and the testing requirements provided an opportunity to compare clinical features of patients whom CDI was detected by targeted testing to those whom CDI was an unexpected finding detected by the multiplex PCR assay. A retrospective observational cohort study was performed on one-hundred forty cases of diagnosed CDI. A comparison of risk factors, clinical presentation, and responses to CDI-specific therapy was done between inpatients and outpatient cases. Analysis of the results showed that inpatients and outpatients were considerably similar in all those categories. There is a significant proportion of the CDI burden, with potential of cases overlooked, in the outpatient setting.