674 Confocal Laser Endomicroscopy for In Vivo Diagnosis of Clostridium Difficile Associated Colitis

Abstract

Confocal Laser Endomicroscopy for In Vivo Diagnosis of Clostridium Difficile Associated Colitis Helmut Neumann, Michael Vieth, Martin Grauer, Raja Atreya, Jonas Mudter, Christoph Becker, Nadine Wittkopf, Markus F. Neurath Department of Medicine 1, University of Erlangen-Nuremberg, Erlangen, Germany; Institute of Pathology, Klinikum Bayreuth, Bayreuth, Germany Background: Clostridium difficile infection (CDI) is one of the most clinically significant causes of hospital-acquired diarrhea and associated with significant morbidity and mortality. Endomicroscopy (CLE) has recently risen as a new emerging endoscopic imaging modality enabling real time in vivo histology during ongoing endoscopy. Aims: Main objective was to investigate whether CLE has the capability for the in vivo diagnosis of CDI. Second objective of our study was to proof the presence of intramucosal bacteria using CLE. Material & Methods: Prospectively, seventy-eight consecutive patients with diarrhea were included of whom eight patients were diagnosed with CDI based on toxigenic culture. CLE was performed after intravenous injection of fluorescein. Additionally, in three patients topical application of acriflavine hydrochloride was performed. In order to validate the presence of intramucosal bacteria ex vivo CLE was performed in pure C. difficile culture; in addition fluorescence in situ hybridization (FISH) was made. Finally, endomicroscopy with fluorescence labelled eubacterial oligonucleotide probes specific for C. difficile was performed in order to prove the presence of intramucosal bacteria. Results: Overall, 80 lesions were examined using endomicroscopy. CLE could readily identify CDIassociated histological changes in vivo. In early CDI, CLE revealed small surface erosions of the superficial colonic crypts and an increased cellular infiltrate. Microvessels within the lamina propria were slightly dilated but showed no leakage. In advanced CDI, CLE demonstrated massively dense cellular infiltrate. Normal colonic appearance was nearly completely abolished and fragile vessels with leakage became visible. Furthermore, a plaque of loosely cells, fibrin and debris covered the mucosal surface. Sensitivity and specificity of CLE in predicting CDI was 75% and 92.9%, respectively. In addition, intramucosal bacteria were visualized using CLE. The presence of these bacteria could also be proven by CLE with fluorescein-labelled specific C. difficile probes and by using the FISH-technique. Sensitivity and specificity for the presence of intramucosal bacteria on endomicroscopy and afterwards confirmed with FISH was 100%. No adverse events regarding the procedure or the use of fluorescence agents were observed. Conclusions: CLE has the potential for the in vivo diagnosis of CDI associated colitis thus enabling accelerated diagnosis and improved patient management. In addition, CLE enabled the detection of intramucosal bacteria in vivo which could open a plethora of new indications in the near future.