The small and the smaller

Biofilms!

Microbes naturally exist as communities usually attached to surfaces. Particularly in aquatic environments, one can find these biofilms attached to almost any surface. That slime that makes you fall as you walk over river rocks is a biofilm!

Our research has focused on a unique aquatic bacteria called Legionella, which is ubiquitous over the entire world and found in a wide array of water systems. These bacteria are found in association with unicellular protozoan and as members of biofilms. Many species are known to cause illness in humans, while others have only been isolated as environmental samples. The primary species isolated from patient material is Legionella pneumophila. The interaction of the bacteria with the host organism is the focus of numerous research programs and it serves as a model organism for facultative intracellular bacteria.

(Photo: Giemsa stain of Acanthamoeba polyphaga with L. pneumophila (dark rods) replicating within vacuoles)

Our Research Interest:

L. pneumophila can persist in the environment for a long time, often in association with biofilms and protozoa. Moist, man-made environments such as cooling towers, whirlpools and showers provide ideal places for contaminating biofilms of Legionella and other species. Aerosalization of bacteria from these biofilms can result in a pneumonia like infection called Legionnaire's Disease. Removal and prevention of such biofilms is difficult due to resistance to disinfectants and biocides as well as the limited use of such agents as regulated by the EPA and other agencies.

Our lab in collaboration with scientists from the Clemson University Department of Chemical Engineering and the Institute for Environmental Toxicology is investigating and developing applications using nanotechnology to remove and inactivate Legionella biofilms in man-made systems. This research is also providing insight in the role of biofilms as sites of bioaccumulation of environmental contaminants.

We are also collaborating with Dr. Sharon Berk's lab at Tennessee Technological University to investigate the interaction of protozoa with Legionella biofilms. Both protozoa and biofilms appear to be effective in the collection of nanoparticles from the environment and our system presents a unique model to studies how nanomaterial contamination may be affecting microbial communities in aquatic ecosystems.