Australian research scientist visits TTU to study Legionnaire's disease

As air conditioning cooling towers work overtime during summer heat here in the United States, leading Australian research scientist Michelle Critchley left the frigid temperatures of her country to visit Tennessee Tech University and further her knowledge of a mysterious killer linked to cooling towers -- Legionnaire's disease.

Critchley, who works for Australia's national science agency, CSIRO, chose a six-week visit to TTU over all other U.S. universities, lured by the chance to collaborate with TTU professor Sharon Berk, a top international researcher with a special interest in Legionella. Australia's worst outbreak of Legionnaire's disease, linked to cooling towers at a newly opened aquarium in 2000, prompted her government to establish a comprehensive strategy to minimize public health risks.

"In Australia, there are strict cooling tower management and operational requirements targeted at minimizing the risk for Legionnaire's disease," said Critchley, who for the last five years has worked with chemical treatments for controlling Legionella in cooling towers. "Whenever a facility installs a cooling tower, it must be registered and is subject to risk assessment.

"Because of this registry, we can use GIS and our database to determine outbreak sources when there are reported illnesses," she explained.

Although the testing of U.S. cooling towers is more infrequent and sporadic, Berk and colleagues have contributed significant research toward understanding how Legionella spreads. Most recently they found that amoebas infected with bacteria are more prevalent in cooling towers than in natural environments. They sampled 40 cooling towers in hospitals, universities and industries and 40 natural environments--lakes, rivers, creeks and ponds--finding infected amoebas in 22 of the cooling towers and only three of the natural samples.

"The bacteria responsible for Legionnaire's disease use amoebas as a host, as do many related bacteria," said Berk, a TTU biology professor.

Berk says Critchley's specialization in molecular biology will complement her own expertise in protozoan ecology. Through this partnership, Berk says that both researchers will be able to learn about each other's work.

"We've discussed the possibility of a collaborative effort in which we will share samples while looking for new species that infect amoebas," said Berk, who says she's not aware of any collaborations in this research area between U.S. and Australian scientists, despite shared concerned.

"I'm excited to have this opportunity to work with a bright, young researcher whose work helps complete the big picture of our studies," Berk said. "I'm so flattered that someone of her caliber chose a trip to our university over any other one in the nation."

Critchley traveled to TTU through the Australian government's "Backing Australia's Ability" program funded by the Australian Academy of Science, which allows researchers to interact with and inform each other to build strong international collaborative teams for future proposals and research.

"I find that U.S. researchers are very passionate about their research," said Critchley.

Critchley shares her work roles between the Australia's national science agency, CSIRO, and Nanotechnology Victoria, the country's premier vehicle for commercializing nanotechnology. As a microbiologist, her interests include anti-microbials, microbial corrosion and bio-sensors. She also has experience in public health risk assessment for water quality and food safety in a variety of client industries.

At Nanotechnology Victoria, she manages a novel drug and vaccine delivery project of considerable promise. She also supports the nanostructured materials team and is involved in nano-safety programs, where her environmental and public health risk assessment expertise is invaluable.

Critchley holds an undergraduate degree (honours) in environmental health from Flinders University, Adelaide, and a doctorate in environmental microbiology, obtained from the same institution. She is currently completing a master's degree in intellectual property law at Monash University in Melbourne.

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