Metronidazole for treatment of norovirus in pediatric transplant recipients

Norovirus is a common cause of gastroenteritis in both immunocompetent and immunocompromised hosts. In transplant recipients, it can lead to prolonged shedding and chronic diarrhea. Treatment with nitazoxanide, oral immunoglobulin, or mammalian target of rapamycin inhibitors has shown varying degrees of benefit in case reports and case series. Prior studies have shown that the commensal gastrointestinal bacterial flora may influence the pathogenesis of norovirus infection. Metronidazole is often used to modulate gastrointestinal flora and was trialed in our hospital for norovirus in some immunocompromised patients after observing an association with anecdotal improvement.

We retrospectively reviewed episodes of norovirus in the stool of 38 patients with a history of solid organ or stem cell transplantation between July 2014 and March 2019.

There were 85 positive norovirus tests among the 38 patients. In 25 of the 85 positive norovirus tests, nitazoxanide was given, with clinical improvement in 15 of these episodes (60%). Eight positive tests were treated with metronidazole alone, in all cases after a course of nitazoxanide had been used. Improvement was observed for 6 of these episodes (75%).

Further investigation of the use of metronidazole for norovirus gastroenteritis in transplant recipients is warranted.