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Published on: April 25, 2025
Enteropathogen detection in children with diarrhoea, or vomiting, or both, comparing rectal flocked swabs with stool
Stephen B Freedman1, Jianling Xie2, Alberto Nettel-Aguirre3
1Sections of Emergency Medicine and Gastroenterology, Department of Paediatrics, Alberta Children's Hospital, Alberta Children's Hospital Research Institute, University of Calgary, Cumming School of Medicine Calgary, AB, Canada.
Insights
Rectal swabs are more effective than stool samples for detecting enteropathogens in children with gastrointestinal symptoms. This finding supports reconsidering rectal swabs for rapid pathogen identification when stool is unavailable.
Area of Science:
- Pediatric infectious diseases
- Clinical microbiology
- Diagnostic technology
Background:
- Traditional enteropathogen detection relies on stool samples, which have low return rates and can cause diagnostic delays.
- Convenient sample collection is crucial for timely and accurate diagnosis of pediatric gastrointestinal infections.
Purpose of the Study:
- To compare the diagnostic yield of rectal swabs versus stool specimens for enteropathogen detection in children presenting with diarrhea or vomiting.
- To evaluate the effectiveness of rectal swabs as an alternative to stool samples in pediatric gastroenteritis cases.
Main Methods:
- A study involving 1519 children under 18 with acute gastrointestinal symptoms was conducted in outpatient settings.
- Rectal swabs and stool specimens were collected and tested using multiplex assays and bacterial culture.
- Statistical analyses, including McNemar's test and generalized estimating equations (GEE), were used to compare pathogen detection rates.
Main Results:
- Rectal swabs showed a higher overall pathogen yield (67%) compared to stool specimens (57%).
- The yield of rectal swabs was particularly advantageous in children without diarrhea at presentation.
- An interaction was observed between diarrhea presence, specimen type, and collection location, influencing pathogen detection.
Conclusions:
- Rectal swabs offer a higher yield for enteropathogen detection compared to stool specimens in children with gastrointestinal symptoms.
- The study recommends reconsidering the use of rectal swabs, especially when rapid diagnosis is needed and stool samples are not readily available.
- Availability of molecular diagnostic technology enhances the utility of rectal swabs for timely enteropathogen identification.
Background:
Enteropathogen detection traditionally relies on diarrhoeal stool samples, but these are inconvenient to collect if they are not immediately available, leading to suboptimum return rates of samples and delayed or missed diagnostic opportunities. We sought to compare the enteropathogen yields of rectal swabs and stool specimens in children with diarrhoea or vomiting, or both.
Methods:
The Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE) did a study in three outpatient cohorts in Calgary and Edmonton (AB, Canada)-children enrolled in the Pediatric Emergency Research Canada emergency departments, children receiving routine vaccinations at a Calgary health clinic, and symptomatic children who met criteria for treatment at home. Eligible participants were children younger than 18 years, with at least three episodes of vomiting or diarrhoea in the preceding 24 h and fewer than 7 days of symptoms. After excluding those enrolled within the previous fortnight, unable to follow-up, or having psychiatric illness, neutropenia, or requiring emergent care, we attempted to collect rectal swabs and stool from all participants. Specimens were tested with the multianalyte assay Luminex xTAG Gastrointestinal Pathogen Panel, an in-house five-virus panel and bacterial culture. Primary outcomes were comparative yield (calculated as the proportion of submitted paired specimens only in which at least one pathogen was identified) and overall yield (which calculated the proportion of study participants in whom at least one pathogen was identified in all specimens, where unsubmitted specimens were analysed as negative). We used McNemar's test to do pathogen-specific analyses, and generalised estimating equations (GEE) for the global (ie, any) pathogen analyses, with adjustments made for the presence of diarrhoea, location, and their interactions with specimen type.
Findings:
Between Dec 12, 2014, and Aug 31, 2016, we studied 1519 eligible participants, 1147 (76%) of whom provided stool specimens and 1514 (>99%) provided swab specimens. 871 (76%) of 1147 stool specimens and 1024 (68%) of 1514 swabs were positive for any pathogen (p<0·0001). Comparative yield adjusted odds ratios (ORs) for stool specimens relative to swabs were 1·24 (95% CI 1·11-1·38) in children with diarrhoea at presentation and 1·76 (1·47-2·11) in children without diarrhoea. GEE analysis identified an interaction between the presence of diarrhoea and specimen type (p=0·0011) and collection location (p=0·0078). In an overall yield analysis, pathogen yield was 57% (871 of 1519 children) for stool specimens and 67% (1024 of 1519 children) for rectal swabs, with an unadjusted OR of 0·65 (95% CI 0·59-0·72) for stool relative to swab.
Interpretation:
Rectal swabs should be done when enteropathogen identification and rapid detection are needed, appropriate molecular diagnostic technology is available, and a stool specimen is not immediately available. In view of their high yield, we urge that the recommendation against the use of rectal swabs as diagnostic specimens be reconsidered.
Funding:
Alberta Innovates-Health Solutions Team Collaborative Research Innovation Opportunity.
