Abstract
This study investigates the performance of diagnostic methods for detection of Clostridioides difficile infection in Sweden, including impact of PCR ribotype on diagnostic performance. Between 2011 and 2016, a total of 17,878 stool samples from 26 laboratories were tested by either well-type enzyme immunoassays (EIAs), membrane bound EIAs, cell cytotoxicity neutralization assay (CTA), or nucleic acid amplification tests (NAATs) and subsequently cultured for C. difficile. Roughly half of the samples (9454/17878) were subjected to diagnostic testing both on the fecal sample and on the 1323 isolated C. difficile strains. All C. difficile isolates were typed by PCR ribotyping, and the isolates were classified as toxigenic or non-toxigenic based on the empirical knowledge of the association between toxin-positivity and ribotype. The overall sensitivity, specificity, and positive and negative predictive values were highest for NAATs and membrane EIAs. Ribotype-specific sensitivity varied greatly between methods and ribotypes. All methods had 100% sensitivity against ribotype 027 and 013. For other types, the sensitivity ranged from 33 to 85% in fecal samples and from 78 to 100% on isolates. For the most prevalent ribotypes (014, 020, and 001), the sensitivity varied between 38 and 100% in the fecal samples, with the lowest sensitivity observed for well-type EIAs and CTA. The large variation in diagnostic sensitivity implies that type distribution significantly affects the outcome when evaluating diagnostic performance. Furthermore, performing comparative studies of diagnostic tests in settings with high prevalence of ribotype 027 will overestimate the general performance of diagnostic tests.
Highlights
Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections worldwide
A total of 17,878 stool samples and 2595 C. difficile isolates were collected for the study, 99 fecal samples (0.6%) tested positive for the presence on toxins A/B (n = 65) or toxigenic C. difficile by nucleic acid amplification tests (NAATs) (n = 34) but were C. difficile culturenegative (Fig. 1)
For 1254/2595 isolates (48%), only the fecal samples were tested for CDI, and the isolates were never subjected to further testing due to the lack of compliance to the study instructions by the local laboratories
Summary
Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections worldwide. A European point prevalence survey accredited 48% of all healthcareassociated gastrointestinal infections to CDI with an attributable mortality of 3% [1]. Toxigenic strains of C. difficile produce one or two major toxins, enterotoxin (toxin A), and cytotoxin (toxin B) encoded by the pathogenicity locus (PaLoc) [2]. Karolinska University Hospital, Huddinge, Sweden 4 Karolinska University Laboratory, Solna, Stockholm, Sweden 5 Department of Laboratory Medicine, Jönköping, Jönköping County, Sweden damage to the enteric cytoskeletal wall and disruption of the tight junctions that connect colonic cells [3]. Some strains produce the binary actin-ADP-ribosylating toxin that increases microtubule polymerization which might increase the adherence of C. difficile to target cells [6]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: European Journal of Clinical Microbiology & Infectious Diseases
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
