A South Bronx boutique hotel was confirmed Thursday as the source of New York City's deadliest-ever Legionnaires' disease outbreak, city Health Commissioner Dr. Mary Bassett said as she declared the flare-up was over.

Twelve people died and 116 others were sickened by the noncontagious form of pneumonia. There has been no new onset of symptoms relating to the South Bronx cluster since Aug. 3 and the incubation period of up to 14 days has passed, Bassett said at the city's public health laboratory in Manhattan's Kips Bay section.

"Most are out of the hospital and are recuperating," she said. "Today, I'm happy to declare that the outbreak is over."

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The hotel's cooling tower had a strain of Legionella bacteria with the same "DNA fingerprint" as 25 samples from patients, some of whom had died, Bassett and Deputy Health Commissioner Dr. Jay Varma said.

The samples were tested by city, state and federal laboratories, Bassett said.

Bassett emphasized that the city will continue to see occasional cases of Legionnaires' disease, which is "ubiquitous."

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The Opera House Hotel in a statement called the test results "obviously disappointing," but noted that city and state officials kept them informed in the past 10 days. Tests completed on Wednesday show its tank is "completely clear of any Legionella pneumophila," the hotel said.

Last week, the hotel criticized city officials as "reckless" for releasing "half-baked information" about its role in the outbreak and said it had been kept out of the loop.

Mayor Bill de Blasio on Tuesday signed into law a mandate that buildings with cooling towers be registered, cleaned and tested regularly.