The state Department of Health is advising Hawai'i residents to thoroughly cook hamburgers, wash vegetables thoroughly and take other precautions to reduce the chance of getting sick from food that might contain a particular strain of E. coli bacterium.

Four E. coli cases were reported to the Health Department between Aug. 12 and 16.

State health director Dr. Chiyome Fukino said there was no common thread in the four cases, including the type of food eaten or where the food was purchased.

Three of the cases involved O'ahu residents, while the fourth was a visitor who probably ingested the E. coli-containing food on O'ahu or the Big Island.

Although most strains of E. coli are harmless and can be found living in the intestines of humans, the E. coli 0157:H7 strain associated with the four recent cases produces a powerful toxin and can cause severe illness, Fukino said.

"If you have bloody diarrhea and severe cramping, go to the doctor," Fukino said.

The strain of E. coli that caused the "cluster" of illnesses in Hawai'i earlier this month infected about 73,000 people nationwide last year and resulted in 61 deaths. Fukino said she was not aware of any E. coli-caused deaths in Hawai'i in recent years, but noted that it is sometimes difficult to attribute deaths to E. coli infections because the illness often leads to severe dehydration resulting in kidney failure, which is then listed as the cause of death.

Reach David Waite at dwaite@honoluluadvertiser.com.