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Published on: September 14, 2013
Use of PCR Cycle Threshold and Clinical Interventions to Aid in the Management of Pediatric Clostridioides difficile
Mohammed Suleiman1, Patrick Tang1,2, Omar Imam3
1Department of Pathology, Sidra Medicine, Doha P.O. Box 26999, Qatar.
Insights
Nucleic acid amplification tests (NAATs) with PCR cycle threshold (Ct) values can accurately diagnose Clostridioides difficile infections (CDI) in children. This approach, combined with toxin reporting, reduced unnecessary CDI treatment by 23%.
Area of Science:
- Clinical microbiology
- Pediatric infectious diseases
- Diagnostic assay development
Background:
- Accurate diagnosis of Clostridioides difficile infections (CDI) is crucial in pediatric patients to avoid overtreatment of colonization.
- Current diagnostic methods for CDI may lack the sensitivity or specificity needed for reliable differentiation between infection and colonization.
- Novel approaches are required to enhance diagnostic precision and guide appropriate clinical management in children.
Purpose of the Study:
- To evaluate the performance of two polymerase chain reaction (PCR) assays (Cepheid GeneXpert and QIAstat-Dx) as standalone diagnostic tools for CDI in children.
- To assess the utility of PCR cycle threshold (Ct) values in predicting toxin presence and differentiating CDI from colonization.
- To determine the clinical impact of reporting toxin production alongside PCR results on CDI treatment rates in a pediatric population.
Main Methods:
- Prospective evaluation of PCR assays (Cepheid GeneXpert, QIAstat-Dx) and toxin testing (C. difficile Quik Chek Complete) on pediatric stool samples.
- Correlation of PCR Ct values with toxin detection to establish cutoffs for differentiating infection from colonization.
- Comparison of CDI treatment rates in pediatric patients 6 months before and after the implementation of the new reporting strategy.
Main Results:
- PCR Ct values demonstrated high sensitivity (100%) at specific cutoffs (26.1 for GeneXpert, 27.2 for QIAstat-Dx) for predicting toxin presence.
- Toxin testing alone showed lower sensitivity (64%) in PCR-positive samples.
- Implementation of the enhanced reporting strategy led to a 23% decrease in CDI treatment rates.
Conclusions:
- Nucleic acid amplification tests (NAATs) combined with PCR Ct value analysis can serve as effective standalone diagnostics for distinguishing CDI from colonization in children.
- Reporting toxin production alongside NAAT results can significantly reduce the overtreatment of colonized children.
- This diagnostic approach improves the accuracy of CDI diagnosis and optimizes antimicrobial stewardship in pediatric care.
Abstract:
Better diagnostic tools are needed to improve the diagnosis of Clostridioides difficile infections (CDI) and reduce the overtreatment of colonized children. In this study, we evaluated two polymerase chain reaction (PCR) assays (Cepheid GeneXpert C. difficile and the Gastroenteritis PCR Panel by QIAstat-Dx) as a standalone method in combination with the PCR cycle threshold (Ct) value in positive samples to predict the presence of free toxins. We also evaluated the clinical impact of reporting toxin production results and provided comments alongside the PCR results in our pediatric population. PCR-positive stool samples from pediatric patients (aged 2 to 18 years old) were included in our study and tested for the presence of toxins A and B using the C. difficile Quik Chek Complete kit. For the clinical intervention, the CDI treatment rates 6 months pre- and post-intervention were compared. The use of PCR Ct value showed excellent sensitivity (100%) at a Ct value cutoff of 26.1 and 27.2 using the Cepheid GeneXpert C. difficile and the Gastroenteritis PCR Panel by QIAstat-Dx, respectively, while the toxin test showed inferior sensitivity of 64% in the PCR-positive samples. In addition, CDI treatment rates were decreased by 23% post-intervention. The results of our study suggest that nucleic acid amplification test (NAAT) assays supplemented by the use of PCR Ct value for positive samples can be used as standalone tests to differentiate CDI from colonization. Furthermore, the reporting of toxin production along with the PCR results can help reduce the unnecessary treatment of colonized children.
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