About This Project

There is speculation that the bacterium, Mycobacterium avium paratuberculosis (MAP), is a causative agent of Crohn's disease (CD). Current diagnostic techniques for MAP are poor. Therefore, it is crucial that we devise new assays to detect for MAP in CD patients. To gain insight into the relationship between MAP and CD, we must sequence the MAP genome and isolate it from CD patient blood. Genomic isolation techniques include PCR amplification and the novel use of hybrid capture probes.

Ask the Scientists

What is the context of this research?

Crohn's disease (CD) is a form of Inflammatory Bowel Disease (IBD) that impacts approximately 700,000 Americans. While there is no known cause for CD, Mycobacterium avium paratuberculosis (MAP) has been proposed as a causative agent. This bacterium is known to cause a gastrointestinal condition in ruminants, called Johne's disease, which has striking similarities to CD. In previous studies, MAP has been shown to be significantly more prevalent in patients with CD (see https://www.ncbi.nlm.nih.gov/p...). Past research, however, has not been able to pinpoint this higher incidence as being causative or correlative. Gathering sufficient genomic data to demonstrate the influence of MAP in CD would greatly advance efforts to find a cure, which remains elusive.

What is the significance of this project?

MAP is a gram-positive, mycobactin dependent, obligate pathogen. The bacterium is routinely spread throughout dairy and beef herds as it is sub-clinically shed from infected cattle. The pathogen can survive pasteurization and chlorination techniques, showing that MAP may be present in our dairy, water, and beef supplies. Crohn's disease, which is the potential result of a MAP infection, is oftentimes debilitating. Symptoms include gastrointestinal bleeding, weight loss, fatigue, stomach pain, and diarrhea. If complications persist, CD can be fatal. Due to the severe nature of Crohn's disease, it would be beneficial to uncover the relationship MAP plays in the condition. Sequencing of the MAP genome is the first step to understanding this relationship.

What are the goals of the project?

The goals of this project are to sequence the MAP genome and then develop a set of methods for the identification of the bacterium, Mycobacterium avium paratuberculosis (MAP), in blood samples obtained from patients with Crohn’s disease. First, we will obtain samples of MAP that have been successfully cultured from blood samples of CD patients. We will then extract DNA from these samples and sequence the MAP genome. After sequencing, we will design a set of MAP-specific PCR primers and use these to PCR amplify MAP. Additionally, we will PCR amplify MAP directly from CD blood samples, as well as design a set of MAP-specific hybrid capture probes, bypassing the need to grow MAP in culture.