Concordance between two enzyme immunoassays for the detection of Clostridium difficile toxins

The reference method influence on the sensitivity of the Clostridium difficile enzyme immunoassays: A meta analysis

The use of enzyme immunoassays to screen for toxins A and B produced by Clostridium difficile is a common procedure in algorithms designed for its detection. Moreover, the absence of a unique test capable of providing reliable results at low cost motivates a great discussion about which algorithm is the best. Thus, several studies have evaluated the performance of these enzyme immunoassays. However, all fail to provide sufficient explanations for the different behaviours observed in different studies that evaluate the same index test against a common reference method. Our main goal was to find out which factors affect the sensitivity of these assays, since the specificity is very close to 1. In this research, we verified that sensitivity increases with the prevalence rate and with the proportion of reported cases of onset diarrhea. Therefore, its use is advisable for high prevalence rates (e.g. in an epidemic setting). As far as reference methods are concerned, nucleic acid amplification tests can be used as a reference method, with a performance similar to the well-accepted toxigenic culture. The method chosen for toxigenicity screening in a toxigenic culture also seems to affect the evaluation performance of tests and should be better studied in the future.

Distribution and risk factor analysis for Clostridium difficile-associated diarrhea among hospitalized children over one year of age

IMPORTANCE

Clostridium difficile-associated diarrhea (CDAD) is a severe type of antibiotic-associated diarrhea (AAD). However, the risk factors for CDAD in children with AAD have not yet been clarified.

OBJECTIVE

To investigate the distribution and risk factors for CDAD among hospitalized children in Beijing Children's Hospital.

METHODS

Stool samples from 197 children with AAD were tested for the C. difficile pathogenic genes (tcdA, tcdB, tcdC, tcdD, tcdE, cdtA, and cdtB) using polymerase chain reaction between January 2011 and January 2014. Children who tested positive for tcdA or tcdB were included in the CDAD group, and those remaining comprised the non-CDAD group.

RESULTS

The rate of CDAD among the 197 children with AAD was 42.6% (84/197). The age distribution was 1-15.6 years, among which the majority of children (54.8%, 46/84) were aged 1-4 years. Differences in the CDAD-positive rates among AAD children belonging to different age groups were not statistically significant. Univariate analysis revealed that the duration of antibiotic therapy, the length of hospitalization prior to diarrhea, and gastrointestinal tract operations were significant risk factors (P < 0.05). Children with CDAD underwent more antibiotic therapy and had longer periods of hospitalization prior to diarrhea onset than children in the non-CDAD group. Using multivariate regression analysis, hospitalization for ≥ 10 days prior to diarrhea was found to be an independent risk factor for CDAD.

INTERPRETATION

This study revealed that the length of hospitalization (≥ 10 days) prior to diarrhea was an independent risk factor for CDAD in children with AAD.

Retrospective analysis of Clostridium difficile infection in patients with ulcerative colitis in a tertiary hospital in China

BACKGROUND

Many reports have documented the increasing impact of Clostridium difficile infection (CDI) in patients with ulcerative colitis (UC). We conducted a retrospective study to determine the incidence, clinical characteristics, risk factors and prognosis of CDI in patients with UC.

METHODS

We studied patients with UC, hospitalized between January 2010 and December 2015 in a tertiary hospital in China. Stool samples were tested for C. difficile toxins A and B (CDAB) by enzyme immunoassays in UC patients with disease flare. CDI in UC patients was diagnosed by clinical symptoms and positive CDAB test, and each case was matched with CDAB-negative patients in a 1:2 ratio. Univariate and binary logistic regression analyses were used to measure the differences between patients with and without CDI.

RESULTS

Thirty-four (8.92%) of 381 patients with UC were CDAB positive. Antibiotic exposure within 3 months prior to the study (P = 0.004), hospitalization within 1 month prior to the study (P = 0.025), systemic use of steroids (P = 0.002) and active cytomegalovirus (CMV) infection (P = 0.001) were higher in CDI than non-CDI patients. Binary logistic regression analysis revealed that CMV infection was associated with CDI (odds ratio = 13.502, 95% confidence interval 1.307-139.512, P = 0.029). UC patients with C. difficile and CMV co-infection had more severe colonoscopic features.

CONCLUSIONS

Recent use of antibiotics, prior hospitalization and systemic use of steroids increased the risk of CDI. CMV infection was an independent risk factor of CDI in patients with UC.