(AP) -- Health officials in Las Vegas said Monday that the bacteria that causes Legionnaires' disease was found in water samples at the Luxor hotel-casino this month after a guest died of the form of pneumonia.
The Southern Nevada Health District said the Centers for Disease Control and Prevention national surveillance program reported three cases in the past year of Luxor guests being diagnosed with the disease caused by Legionella bacteria.
The Las Vegas Strip resort's water was tested after the first two cases were reported during the spring of last year, but no Legionella bacteria was detected, district officials said. Those guests recovered.
Officials say the Luxor, owned by MGM Resorts International, immediately began a remediation process once the bacteria was found.
MGM Resorts spokesman Gordon Absher said treatment procedures include superheating and super-chlorination of the water system.
"We are confident in the integrity of our systems and the safety protocols we follow at all our hotels. Guest and employee safety is always a top priority at our company," Absher said. "Even before last summer, MGM Resorts led the industry with aggressive and stringent programs to control Legionella issues common to all large buildings."
Absher said the company's resorts regularly test for Legionella and treat water systems preventatively, before bacteria are detected.
The new cases come as the company is already facing a civil lawsuit from guests who said they were infected with Legionella at the Aria Resort & Casino, part of the CityCenter complex that is half-owned by MGM Resorts.
MGM Resorts notified guests that they might have been exposed to the bacteria between June 21 and July 4 after the district reported six cases of Legionnaires' disease in July. The district said those guests recovered after treatment.
Eight guests sued in August, seeking $337.5 million in damages from the resort and its builders. An MGM Resorts spokesman at the time denied negligence, saying hotel officials carefully communicated with its guests and reimbursed them fairly for legitimate medical expenses. The case is still pending in federal court in Las Vegas.
Legionella is commonly found in the environment in fresh water, the district said. Symptoms of Legionnaires' disease usually begin within two weeks of being exposed to the bacteria, the district said.
Most people who are exposed to the bacteria don't get sick, according to the CDC. Smokers, people over age 50 and those who have chronic lung disease or weak immune systems are most susceptible, the CDC said.
The bacteria isn't spread between people. It grows most often in warm water, infecting people when they breathe in mist or vapor that has been contaminated.
District officials said between 8,000 and 18,000 people are hospitalized with Legionnaires' disease each year, and can cause death in up to 30 percent of cases. Officials said as many as one-fourth of reported Legionnaires' cases are associated with travel, so health investigators typically ask for travel histories when they look into individual cases.
The disease takes its name from an outbreak at the Pennsylvania American Legion convention held at the Bellevue-Stratford Hotel in Philadelphia in 1976.