‘High-risk exposure’ to deadly bacteria with 50% fatality rate

Staff at a laboratory in Arizona were exposed to deadly bacteria that cause melioidosis, a disease with a 50% fatality rate, according to a new medial journal report.

The previously unrevealed exposure occurred in 2021 at the microbiology lab at the Mayo Clinic Arizona in Phoenix. The clinic’s staff were examining a swab sample from a 58-year-old patient.

Three employees were later identified as exposed — and one was singled out as a “high-risk exposure.”

The employee with high-risk exposure “performed an aerosolizing procedure outside of the biologic safety cabinet,” according to the report published in the journal Emerging Infectious Diseases.

That employee also had a preexisting condition that could make them more vulnerable to illnesses.

The bacteria, known as Burkholderia pseudomallei, was seen only in tropical Asia and Australia, but has now spread across the world to the Gulf Coast region, according to an alert this week from the Centers for Disease Control and Prevention.

Because B. pseudomallei is rarely seen in the US, the laboratory staff had an “initial lack of clinical suspicion” for the bacteria, the report authors noted.

As a result of its rarity, melioidosis is often misdiagnosed as sepsis or another condition.

“This is one of those diseases that is also called the great mimicker because it can look like a lot of different things,” Julia Petras, an epidemic intelligence service officer with CDC’s National Center for Emerging and Zoonotic Infectious Diseases, told HealthDay News.

“It’s greatly under-reported and under-diagnosed and under-recognized — we often like to say that it’s been the neglected tropical disease,” Petras added.

This makes melioidosis a serious problem because early diagnosis is critical to treating the disease.

“We have antibiotics that work,” Petras said. “It’s extensive treatment, but if you’ve finished the full course and you’re diagnosed early, which is the really key thing, your outcome is probably going to be quite good,” she added.

The days when melioidosis was a rare tropical disease may be over: The B. pseudomallei bacteria that causes the illness has now been declared endemic (or commonplace) along the entire Gulf Coast from Florida to Texas.

The CDC made this declaration after several cases of melioidosis were reported in Mississippi. A warming climate is considered a key factor in spreading this and other diseases that were once confined to the tropics.

Symptoms of melioidosis can appear one to four weeks after exposure, according to the Cleveland Clinic. Symptoms include a persistent cough that may be bloody, fever, weight loss and pain in the stomach, chest, muscles or joints.

All the Arizona lab staff were monitored for several weeks, and none tested positive for melioidosis. But, the report’s authors noted, “US laboratories should remain vigilant for and aware of the growth characteristics associated with B. pseudomallei to help avoid occupational exposure.”

Other exposed people weren’t as lucky as the lab staff: In 2021, four people were infected with B. pseudomallei that was contained in an aromatherapy room spray sold by Walmart.

One of the adult patients died, and a second adult patient survived but was left with severe health problems, according to case studies published in the New England Journal of Medicine.

Two children were also treated for melioidosis: a 4-year-old girl survived but was wheelchair-bound and unable to speak, and a 5-year-old boy eventually died.