The Laboratory Diagnosis of Clostridioides difficile Infection: An update of current laboratory practice.

Ali Mohammed Somily,Muhammad Morshed,Mohammad Aatif Khan

doi:10.3855/jidc.13217

Abstract

Clostridioides difficile can cause colitis and is associated with hospital acquired infections. The C. difficile infection (CDI) is due to production of toxins A and B which bind to epithelial cell surface receptors and triggers signaling pathways, leading to loss of epithelial barrier function, apoptosis, and inflammation, culminating in diarrheal disease. In early days, laboratory diagnosis of CDI was based on cell culture, identification of toxins, and their cytopathic effects. These assays were replaced by enzyme immunoassays for the detection of C. difficile toxins and the GDH house-keeping gene for improved specificity. Later, molecular assays with higher sensitivity were introduced which are becoming easier to incorporate into the test algorithm. The diagnosis of CDI and significance of laboratory results can be challenging with asymptomatic colonization of C. difficile in some patients. Test result interpretation is even more challenging due to multiple guidelines, emerging resistant C. difficile ribotypes, as well as differences in disease prevalence. An accurate test result for diagnosis of CDI depends on selecting patients with high pre-test probability, collecting an acceptable stool specimen, and a thorough understanding of current test methods.

Highlights

Clostridioides difficile is an anaerobic, spore-forming Gram-positive bacillus responsible for toxin-mediated gastrointestinal disease, ranging from mild to life threatening infection in some patients
This review article will focus on C. difficile infection (CDI) diagnosis and emphasize the current practice in laboratory diagnosis and the preanalytical issues related to quality of specimen that influence the pre-test probability of CDI
Et al – Update in Laboratory Diagnosis of Clostridioides difficile known as cell culture cytotoxicity neutralization assay (CNA) and toxigenic culture (TC) are considered as gold standard reference tests for detection of C. difficile

Summary

Introduction

Clostridioides difficile (formerly known as Clostridium difficile) is an anaerobic, spore-forming Gram-positive bacillus responsible for toxin-mediated gastrointestinal disease, ranging from mild to life threatening infection in some patients. The EIA test is simple, cost-effective, and rapid; some studies have shown that its analytical sensitivity is low compared to the gold standard CNA and TC for detecting C. difficile toxins [6] This has led to a search for a better test that is more sensitive and specific; subsequently, the molecular method known as the Nucleic Acid Amplification test (NAAT), which detects C. difficile toxin genes in stool specimens, was introduced and approved as a diagnostic test by FDA and other health regulatory agencies [6]. In spite of some cross reactivity with other clostridial species, manually designed primers were able to amplify intended gene targets with better sensitivity than anaerobic culture-based tests and CNA [35] These findings were early indicators that nucleic acid amplification tests (NAAT) could be a better platform for the accurate and timely detection of C. difficile. Interpretation of results and their clinical relevance require detailed review and analysis by experienced microbiologists

Molecular tests for Public Health uses PCR Ribotyping

Findings

Conclusions