Detection of cytomegalovirus (CMV) by real-time PCR in fecal samples for the non-invasive diagnosis of CMV intestinal disease

Background: Cytomegalovirus (CMV) infection of the gastrointestinal tract can cause CMV intestinal disease (CMV-ID), a severe complication in immunocompromised patients. Current gold standard for diagnosing CMV-ID requires the analysis of colon biopsies. Testing of fecal samples by CMV PCR might be a non-invasive diagnostic alternative, but data on this method is scarce. Objectives: To evaluate the use of quantitative CMV real-time PCR in fecal samples for diagnosing CMV-ID. Study design: Fecal samples and lower intestinal tract biopsies from 66 patients were analyzed by quantitative CMV PCR. To evaluate the diagnostic significance of CMV detection by PCR in fecal samples, patients were classified according to the etiology of their intestinal disease (based on results of endoscopy, histopathology and quantitative CMV DNA detection in biopsies) into three groups: "CMV-ID", "non-CMV-ID", and "equivocal". Results: 10/66 fecal samples were tested positive by quantitative CMV PCR, but CMV DNA loads were low( range <1000-11,000 copies/ml). CMV detection by PCR in fecal samples was positive in 8/12 patients of the CMV-ID group, resulting in a sensitivity of 67% for diagnosing CMV-ID. With two exceptions, fecal CMV PCR was negative in the non-CMV-ID group (45/47) indicating a good specificity (96%). Moreover, CMV DNA detection in feces was associated with high CMV DNA levels in intestinal biopsies. Conclusions: Negative CMV PCR results from fecal samples cannot exclude CMV-ID and thus have to be confirmed by analyzing intestinal biopsies. However, positive fecal PCR results are diagnostically useful and might help to circumvent invasive diagnostic procedures as endoscopy. (C) 2014 Elsevier B.V. All rights reserved.