Estimating risk of c. difficile transmission from pcr positive but cytotoxin negative cases

Abstract Background: The use of molecular methods to diagnose Clostridium difficile infection (CDI) has improved diagnostic yield compared to conventional methods. However, PCR testing can detect colonization and has introduced several practical challenges pertaining to need for treatment and isolation of cases

PCR threshold cycle value (Ct) for forty-two samples tested by Cytotoxin assay (CYT) and PCR.

<p>PCR threshold cycle value (Ct) for forty-two samples tested by Cytotoxin assay (CYT) and PCR.</p

Minimum spanning tree of MLVA data from study isolates (n = 47).

<p>Letter symbol in the center of the circle represents the results for testing by cytotoxin assay for 42 samples included in the analysis (C + and C −). Five samples were not tested by CYT (NT). Each circle represents a distinct MLVA type and numbers between the circles represent the STRD [Summed tandem repeat difference]. Isolates with a STRD<10 are highlighted in colored clouds representing clusters (genetically related clonal complexes). <i>tcdC</i> sequencing is depicted by color coding within circles with <i>tcdC 1</i> (corresponding to NAP1) strain represented in red (reference in right corner).</p