Walker Lab

The Walker lab is focused on understanding the host-pathogen interactions that dictate the onset, course, and outcome of chronic infections.

Our work uses infections of medical devices as a model for chronic disease. By defining the bacterial and host mechanisms the facilitate these recalcitrant infections, we seek to develop novel antibiotic sparing therapies that can effectively treat common and costly diseases. We use a multidisciplinary approach to blend the use of basic science, model systems, and patient samples to pursue the following questions:

1. How do medical devices become infected?

Millions of medical devices are placed every year and their use is expected to increase due to their efficacy at improving the length and quality of life. However, infections of medical devices are a common, dreaded complication. Despite their prevalence, it is unclear whether device infections occur due to contamination by bacteria from the hospital setting or through the persons’ own microbiome. Additionally, whether certain bacteria or virulence factors are more likely to cause symptomatic vs asymptomatic infection remains unknown. We collaborate closely with physicians and use a combination of model systems, patient samples, and genomics to understand how bacteria initiate device colonization and translate these discoveries into better surveillance, prevention, and treatment strategies.

2. How do medical devices render people susceptible to infection?

It is a well-known phenomenon that medical devices render people susceptible to atypical or “less pathogenic” bacteria, yet the mechanisms responsible remain largely unknown. Our recent studies indicate the device itself induces inflammation, which may prevent the host from mounting an effective response against these “less pathogenic” bacteria, allowing them to cause disease. To define these interactions, we are combining the use of model systems and patient samples to understand the inflammatory response to devices with and without infection. This work involves immunology, microbiology, and biochemistry for the identification of biomarkers that predict infection risk and the development of better device materials that reduce infections.

3. What are the bacterial mechanisms that facilitate medical device infections?

Staphylococci are the primary cause of device infections and form recalcitrant biofilms on the device surface. Our group recently discovered that staphylococci use different adhesins to attach to various host proteins coating device surfaces to initiate biofilm formation. This work uses bacterial genetics and molecular microbiology to understand the host-pathogen-device interactions that facilitate infection to develop novel antibiotic-sparing treatment strategies.