A seventh person has died after being infected with the O-157 strain of E. coli bacteria in a food-poisoning outbreak in Utsunomiya, Tochigi Prefecture, according to a local public health center.

The center said an 87-year-old woman died Friday and two women, aged 58 and 76, became critically ill. All three had been admitted to a private hospital where they apparently contracted the deadly bacteria.

A 10-month-old boy was among those who died earlier.

The poisoning, which broke out at Hotokukai Utsunomiya Hospital and its adjacent nursing home, has affected more than 100 people. Eight remain seriously ill.

According to the center, the 87-year-old woman complained of bloody feces Aug. 5 and was transferred to another hospital three days later. She died from heart failure and hemolyric uremic syndrome, which typically follows an E. coli infection.

Among the latest to fall seriously ill, the kidneys of the 58-year-old woman are not functioning properly, while the 76-year-old is suffering from encephalitis, an inflammation of the brain, the center said.