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Etiologic Diversity and Diagnostic Yield of Multiplex PCR in Children With Bloody Diarrhea: A Prospective Study in a
Yılmaz Seçilmiş1, Soner Sertan Kara2
1Department of Pediatrics, Division of Pediatric Emergency, Erciyes University, Faculty of Medicine, Kayseri.
Insights
Pediatric bloody diarrhea has diverse causes, not always bacterial. Multiplex PCR and stool culture together offer the most comprehensive diagnosis for children with hematochezia.
Area of Science:
- Pediatric Gastroenterology
- Infectious Diseases
- Clinical Microbiology
Background:
- Acute bloody diarrhea (hematochezia) in children is often presumed to be bacterial, but its causes are varied.
- Understanding the etiologic spectrum is crucial for appropriate diagnosis and management.
- Diagnostic methods, including multiplex PCR and conventional stool testing, need comparative evaluation.
Purpose of the Study:
- To determine the causes of acute bloody diarrhea in children presenting to a pediatric emergency department.
- To compare the diagnostic yield of multiplex gastrointestinal PCR versus conventional stool testing.
- To assess if clinical severity predicts bacterial etiology in pediatric bloody diarrhea.
Main Methods:
- Prospective observational study of children (0-18 years) with hematochezia.
- Stool samples analyzed using conventional methods (culture, antigen, microscopy) and a 22-target multiplex PCR panel.
- Clinical severity assessed using the Clinical Dehydration Scale (CDS) and modified Vesikari score.
Main Results:
- An enteropathogen was detected in 74.7% of 83 enrolled children.
- Bacterial pathogens were found in 44.6%, viral in 16.9%, and parasitic in 13.3%.
- Multiplex PCR identified more bacterial pathogens than culture alone, but culture detected 27% of bacterial pathogens missed by PCR.
Conclusions:
- Pediatric acute bloody diarrhea is etiologically diverse, with bacterial infections not always predominant.
- Clinical severity did not reliably predict bacterial etiology.
- Comprehensive testing combining stool culture and multiplex PCR is recommended for optimal diagnosis.
Objectives:
Acute bloody diarrhea (hematochezia) in children is traditionally associated with invasive bacterial infection, but its etiologic spectrum is increasingly recognized as heterogeneous. We aimed to characterize the etiologic distribution of acute bloody diarrhea in a pediatric emergency department and to compare the diagnostic yields of multiplex gastrointestinal PCR and conventional stool testing.
Methods:
In this prospective observational study conducted between July 2018 and July 2019, consecutive children aged 0 to 18 years presenting with visible blood in stool (hematochezia) to a tertiary pediatric emergency department were enrolled. Disease severity was assessed using the Clinical Dehydration Scale (CDS) and the modified Vesikari score. All stool samples were tested with conventional methods (culture, antigen for rotavirus/adenovirus, microscopy) and a 22-target commercial multiplex gastrointestinal PCR panel. The contribution of multiplex PCR was analyzed as a descriptive diagnostic yield rather than as a predictor in a regression model, and a multivariable logistic regression model containing clinical variables only was used to test whether clinical severity independently predicted bacterial etiology. A sensitivity analysis used a stricter culture-confirmed definition of bacterial etiology.
Results:
Eighty-three children were enrolled (median age 48 mo, IQR 21 to 84; 55% male). At least 1 enteropathogen was detected in 62 patients (74.7%). A bacterial pathogen was identified in 37 of 83 patients (44.6%), a viral-only infection in 14 (16.9%), a parasitic infection in 11 (13.3%), and a mixed viral-bacterial co-detection in 4 (4.8%). Of the 37 bacterial detections, 10 (27.0%) were identified by stool culture alone, 22 (59.5%) by multiplex PCR alone, 1 (2.7%) by both culture and PCR, and 4 (10.8%) by combined antigen and PCR in mixed infections. In the multivariable logistic regression model, none of CDS ≥5, fever, continuous modified Vesikari score, or recent antibiotic use was independently associated with bacterial etiology. Culture and PCR were complementary: 27.0% of bacterial pathogens were detected only by culture despite a negative bacterial PCR target.
Conclusions:
Pediatric acute bloody diarrhea is etiologically heterogeneous: fewer than half of the presentations had a bacterial etiology, and clinical severity alone did not reliably identify those with bacterial infection. Multiplex PCR expanded-but did not replace-stool culture, with more than a quarter of bacterial pathogens detected only by culture. Clinical management of children with bloody diarrhea should combine maintained clinical vigilance with comprehensive microbiological testing (stool culture plus multiplex PCR).
