Evaluation of the Cepheid ® Xpert ® C. difficile binary toxin (BT) diagnostic assay

An Update on Clostridioides difficile Binary Toxin

Infection with Clostridioides difficile (CDI), a common healthcare-associated infection, includes symptoms ranging from mild diarrhea to severe cases of pseudomembranous colitis. Toxin A (TcdA) and toxin B (TcdB) cause cytotoxicity and cellular detachment from intestinal epithelium and are responsible for CDI symptomatology. Approximately 20% of C. difficile strains produce a binary toxin (CDT) encoded by the tcdA and tcdB genes, which is thought to enhance TcdA and TcdB toxicity; however, the role of CDT in CDI remains controversial. Here, we focused on describing the main features of CDT and its impact on the host, clinical relevance, epidemiology, and potential therapeutic approaches.

Clostridioides (Clostridium) difficile-associated disease: Epidemiology among patients in a general hospital in Saudi Arabia

BACKGROUND

Clostridioides (Clostridium) difficile infection (CDI) is an important health care-associated infection with variable incidence and prevalence across the globe. There are limited data from Saudi Arabia on the epidemiology of C. difficile-associated diarrhea (CDAD). In this study, we present the epidemiology and incidence of CDAD in a hospital in Saudi Arabia.

METHODS

This study included all stool samples from 2001 to 2018 that were tested for C. difficile. C. difficile toxins were detected by enzyme-linked immunosorbent assay in 2001-2012 and the diagnosis was based on PCR testing (2013-2018).

RESULTS

There was a total of 577 distinctive episodes of CDAD representing 5.2% of 10,995 tested stool samples with an annual positivity rate of 0.9%-11.8%. Of all CDAD cases, there were 230 (39.9%) community associated-CDAD, 105 (18.2%) community onset-health care facility associated disease, and 242 (42%) health care facility onset health care facility-associated disease (HCFO-HCFAD). There was a trend of increasing percentage of community onset-health care facility associated disease cases from 17% in 2001 to 20% in 2018 of all cases, and a trend towards less cases of community associated-CDAD from 85% to 50% over time. However, the percentages of HCFO-HCFAD percentages remained relatively stable. The rate of HCFO-HCFAD per 1,000 patient-days increased from 0.009 to 0.22 from 2001 to 2018, respectively.

CONCLUSIONS

The rate of CDAD was 5.15% among all tested samples and that there is a large proportion of community associated-CDAD. The findings parallel the data from developed countries and deserve further studies in the risk factors for community-associated CDAD.

Direct detection and characterization of Clostridium difficile from a novel collection device to improve laboratory workflow

Emergence of Clostridium difficile strains with increased virulence emphasizes the importance of early diagnosis and surveillance of C. difficile infection (CDI). In this study, the new FecalSwab™ collection and transport system was evaluated to improve C. difficile diagnosis. The FecalSwab™ was used for direct C. difficile molecular detection, C. difficile culture/toxigenic culture (TC) and bacterial genomic DNA (bgDNA) extraction. Our results demonstrated that the FecalSwab™ medium could be successfully used as template for Xpert C. difficile binary toxin (BT), regardless of the bacterial load of samples, and for C. difficile culture also after a long storage (30 days) of FecalSwab™ tubes at 4 °C. Furthermore, good-quality bgDNA was extracted from the FecalSwab™ medium for the majority (75%) of the samples analyzed. Typing was performed to fully characterize C. difficile strains isolated during this study and 17 different PCR-ribotypes (RTs) were identified. The results obtained indicate that the FecalSwab™ can be successfully used not only in daily diagnostic routine of C. difficile but also in surveillance and retrospective studies.