Biofilm Interactions

Legionella! Legionella! Legionella! What is it? Why do the Centers for Disease Control and Prevention care about it? And why has the McNealy Lab decided to investigate it? Legionella is a bacterium that causes a type of pneumonia and can be found almost anywhere there is fresh water. It is the number one cause of waterborne disease outbreaks in the U.S. and is estimated to hospitalize 8,000 – 18,000 people a year here in the U.S. One reason that Legionella causes so many outbreaks is by its ability to persist in a biofilm. A biofilm is a group of bacteria and other organisms that live together to better protect themselves from the environment. Although some research has been done, little is known about Legionella biofilms.

The Creative Inquiry, Biofilm Interactions, studies such biofilms in hopes of achieving a better understanding of how biofilms interact with the environment, ultimately to help prevent future outbreaks of Legionella. Dr. Tamara McNealy, associate professor of Microbiology, leads this Creative Inquiry team in building and designing personal and group projects to help better understand biofilms.

One of the ongoing projects in the lab is to understand the life cycle of the biofilm and to determine how biofilms respond to the various environmental stressors to which they are normally exposed. The group also investigates how genes are expressed. Much of the investigation uses confocal microscopy, which generates multi-color, 3D images of the biofilms. This technique was a relatively new way of looking at gene expression in biofilms. The lab worked closely with the Clemson Light Imaging Facility (CLIF) to perfect the protocols. Once trained, undergraduate students work independently in the facility to acquire and analyze their images.

This Creative Inquiry also explores the composition of a Legionella biofilm. Bacteria in a biofilm secrete products, primarily proteins, polysaccharides and extracellular DNA, to build a matrix that supports and protects the organisms within. Each matrix is specific to the bacteria in the biofilm. Components of the matrix are targets for biofilm disinfection and eradication strategies. Understanding the components of a biofilm matrix could help predict how biofilms will respond to the environment and help develop novel eradication techniques such as the use of nanoparticles.

Nanoparticles are particles ranging from 1 to 100 nanometers and can be composed of many different materials. In addition to the possible use in biofilm eradication efforts in man-made environments, nanoparticles are also found in many products we use, such as cosmetics or sunscreen. As a result, nanoparticles are released into our environment, and can eventually settle onto microbial biofilms. The long-term impact of nanoparticles on native biofilm composition and function is unknown. With the growing use of nanoparticles and the limited understanding of their ecological impact, the work that this Creative Inquiry is doing provides an excellent opportunity to generate data that can affect environmental health and safety concerns and policy.

McNealy stated, “The work conducted by the undergraduates on the team has provided essential data from which the project continues to grow. Experiments that give you interesting data that enable you to then ask more questions is how science progresses. This happens in this group.” The McNealy Lab is a dynamic place with three graduate students and up to ten undergraduates participating in any given semester. Each undergraduate receives mentoring from Dr. McNealy and the graduate students. There is always someone to talk to and ask questions. Bethan Fanning, a senior Microbiology major, shared, “In this lab, we are each given our own unique projects, allowing us to learn how to plan an experiment, think critically through any problems we encounter, and interpret data. Through my experience, I have gained a greater understanding of scientific research and microbiology, far beyond what I could have learned in classes alone.”

Students also engage other scientists, peers and the public through presentation of their research at professional conferences. Recent presentations were made at conferences in Charleston, Boston, and Australia, including meetings of the national and regional American Society of Microbiology. The lab also presents at events sponsored by Clemson, including the Focus on Creative Inquiry Forum (FoCI) and the Clemson Biological Sciences Annual Student Symposium (CBASS).

The research activities of the Biofilm Interactions Creative Inquiry provide invaluable experiences for the students and advance the study of microbiology and biofilms.