Article in Japanese

Decolonization of pediatric long-term Escherichia coli O157 carriers using azithromycin: A report of two cases

Shuta Ishikawa^1）, Toshiki Sato^1）, Kazune Tsunokake^1）

Here, we present two pediatric patients who became long-term Escherichia coli O157 carriers following enterohemorrhagic E. coli （EHEC） infection complicated by intussusception and were successfully decolonized using azithromycin. The first patient was a 3-year-old girl presented with fever, abdominal pain, and bloody stools and diagnosed with intussusception using air contrast enema. Intussusception was reduced with high-pressure enema. Stool cultures led to the diagnosis of EHEC infection with the O157 strain. The patient was discharged and prohibited from attending school until stool test became negative. However, E. coli O157 persisted for approximately 1 month, requiring azithromycin treatment, which led to rapid decolonization without complications. The second patient was an 8-year-old girl with similar symptoms who was also diagnosed with intussusception and treated with high-pressure enema. E. coli O157 was detected in stool cultures. The patient could not return to school for 3 weeks due to persistent E. coli O157, which could be promptly eradicated with azithromycin treatment. Although antibiotic therapy is associated with an increased risk of hemolytic–uremic syndrome in patients with EHEC infection, prolonged school exclusion of asymptomatic carriers can place a significant social burden. Azithromycin should be considered a safe and effective method for decolonization in pediatric E. coli O157 carriers.

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1）Depaetment of Paediatrics, Iwate Prefectural Ninohe Hospital

Key words	enterohemorrhagic Escherichia coli （EHEC）, O157, long-term carriers, school exclusion, azithromycin
Received	February 5, 2025
Accepted	July 29, 2025

37 (3)：259─265,2025