Five children have been treated for kidney failure after an E. coli outbreak at a preschool in Ansan, Gyeonggi Province, health authorities said Friday.

Senior official Kim Jae-seon at Ansan Sangnoksu Health Center, which is investigating the outbreak, said 15 preschoolers have come down with suspected cases of hemolytic uremic syndrome -- a form of kidney failure associated with E. coli infection.

“We are still in the process of identifying the source of contamination and grasping the size of the outbreak,” she said.

The children are “believed to be in stable condition,” she said, adding that one of the five on dialysis has been taken off renal therapy this morning.

According to the Korea Centers for Disease Control and Prevention, up to 15 percent of those infected with E. coli develop this condition which can be fatal, especially among children.

Pediatric infectious specialist Dr. Eun Byung-wook of Nowon Eulji University Hospital in northern Seoul said while most children recovered from the syndrome over a few months’ time, some could suffer longer-lasting health problems.

“The fact that the children had to be put on dialysis means it’s highly likely they have developed this complication known as the HUS,” he said. “If the kidney injury from the infection turns out to be irreversible, patients may require a transplant because they cannot remain on dialysis forever.”

Since the first patient was found at the preschool June 18, the city’s officials have tested 295 people linked to the outbreak to find that 49 were positive for E. coli, with 99 more awaiting results. At least 102 have reported experiencing symptoms such as diarrhea, bloody stools, vomiting, dizziness and fever. Of the 32 hospitalized, only nine have been discharged with the rest still undergoing treatment.

By Kim Arin (arin@heraldcorp.com)