Acute Pediatric Gastroenteritis: Do You Need to Find the Etiology?

William T. Basco, Jr, MD, MS


December 27, 2016

Causative Agents in Gastroenteritis

Norovirus is now the leading cause of gastroenteritis among children in the United States since universal rotavirus vaccination was implemented. In most cases of gastroenteritis, practitioners are unaware of the etiologic agent causing the acute symptoms. Previous diagnostic approaches probably contributed to the low identification of causative agents because of single-pathogen testing methods, the cumbersome nature of some methods, and the low sensitivity of other methods.

However, multiplex nucleic acid-based tests are available now. A recent study[1] sought to evaluate causes of acute gastroenteritis using this testing, along with a polymerase chain reaction (PCR) test for two additional pathogens, to determine etiologies of acute gastroenteritis in a sample of children from Nashville, Tennessee.

The children were cared for between 2008 and 2011 as part of an ongoing surveillance project funded by the Centers for Disease Control and Prevention. The definition of acute gastroenteritis was three or more loose stools and/or more than one episode of vomiting within 24 hours.

Children were enrolled if they presented within 10 days of onset of symptoms to an inpatient, emergency department, or outpatient setting. All children were between the ages of 2 weeks and 6 years. The children's stool samples were tested for pathogens and were compared with those of healthy control children who provided samples in 2009.

Study Findings

There were 216 children with acute gastroenteritis, of whom 54% were boys, and the median age was 16 months. A majority (69%) of the children had been breastfed at some point, and 11% were still being breast-fed at the time of study.

Overall, at least one pathogen was identified in 70.4% of the children with gastroenteritis, compared with only 11% of the asymptomatic healthy children. Viral pathogens predominated and were isolated from 63.9% of the acute gastroenteritis group. Bacteria were identified in 21.8% of the children with gastroenteritis, of which 75% were Clostridium difficile. Among the virus-positive samples, norovirus accounted for 57% and rotavirus for 20%. No protozoans were identified.

Among the whole cohort, more than one pathogen was identified in 22.7% of the children. Of interest, among the children positive for C difficile, 71% also were positive for a second organism.

Norovirus was the single most common pathogen overall, accounting for 36.1% of all cases of acute gastroenteritis. The children with viral pathogens were slightly older, with a median age of 19.5 months compared with 10 months for those with a bacterial pathogen. The duration of hospitalization was longest among the children with no pathogen detected at 2 days, and lowest among children with a bacterial pathogen at 0.5 day.

The authors concluded that broad molecular testing with nucleic acid-based testing and PCR can identify pathogens in a majority of acute cases of gastroenteritis in children.


I wanted to review this article mostly for the epidemiologic information it provides. These data certainly suggest that the new multiplex panels are very effective at identifying pathogens.

The challenge, however, is what to do with the information, and the authors fully explore this issue in their implication statements and the broader discussion section. As the authors rightly note, the coinfection of so many of the children with C difficile and another pathogen raises the distinct probability that a good portion of these pathogens represent colonization. In addition, they note that knowing the organism will not affect management for a large number of children with acute gastroenteritis.

Given the cost of these tests, it is absolutely true that we should be thoughtful about applying them only to cases in which knowing the organism involved has the potential to influence treatment, and that would probably end up being a relatively small subset of all patients with acute gastroenteritis.