A notice to boil drinking water has been imposed across the city for all City of Cape Coral Water Utility customers, impacting 190,000 people according to local radio station WGCU. City authorities said residents should either use bottled water or boil their water for more than a minute to kill any E. coli present before it is consumed.

On Monday night, officials said they had flushed suspect plants and increased chlorine usage in a bid to kill the infection. They hoped to fix the problem within 72 hours.

Bottled water and hand sanitizers are being delivered to local schools, with cafeteria staff told to “follow appropriate boil notice procedures to ensure food is safe for consumption,” they said.

E. coli can cause sickness and diarrhea, along with kidney failure and death in the most extreme cases, according to the Department of Health and Human Services. The infection is most dangerous to children and adults with weak immune systems.

In a statement, the Cape Coral government said: “A Citywide boil water notice has been issued, effective immediately for all City of Cape Coral Water Utility customers, due to E. coli bacteria present in two separate samples.

“We advise residents to boil water for one minute or use bottled water as a precaution until the advisory has been lifted. This notification applies to water used for drinking, cooking, making ice, washing dishes, and brushing teeth.”

The city’s website said showers and washing clothes in tap water “are not restricted by the boil water notice.”

Cape Coral authorities did not specify in which two places the E. coli bacteria was detected.

Florida averages 59 recorded E. coli cases a year, according to the Florida Department of Health. Patients generally report no or a very mild fevers, unlike with other bacterial diarrheal infections, which can be more severe.

Professor Anna Yeung-Cheung, an expert in microbiology at Manhattanville College in New York state, told WGCU it was vital that authorities act quickly.

“This is not good. They need to investigate. It’s a lot of work. Especially in coastal towns. Especially in Florida,” she said.

“It can take years to do all the work that it takes to discover what it is. But they really need to find it out,” Yeung-Cheung said of the source of the infection.

An E. coli outbreak in Michigan and Ohio infected 29 people last month, nine of whom required hospital treatment.

In July, ground beef sold across seven states was recalled due to E. coli fears. The same month, an international team extracted the oldest known sample of E. coli from a mummified 16th century body in Italy.