Examination of phage resistance and susceptibility in M tuberculosis

Much is unknown of mechanisms of bacteriophage resistance and susceptibility in Mycobacterium tuberculosis (Mtb) and are still unsolved. Studies have provided useful classification schemes, such as whole genome sequencing and spoligo typing using DNA sequences. Unfortunately, DNA sequencing has not provided a clear understanding or basis for explaining the biology of phage typing or phage/host interactions in Mycobacterium tuberculosis at a time when phage therapy may provide a possible solution to treatment in the face of the ongoing problem of the worldwide drug resistant epidemic in tuberculosis. Bacteriophages have the potential to provide a new molecular approach for treating drug-resistant tuberculosis. However, in order to develop these effective phage therapies, we need to better understand the biology of phage-host interactions in Mtb. In this study, we propose to examine phage-host interactions using an established stock of phages from decades-old archived collection of Mtb phages. This will be accomplished through three specific aims: 1) Determine the similarities and differences that determine phage host range. We will characterize the distinctive properties of these phages by their host range limitations, morphological and DNA sequencing differences and similarities, and phage attachment properties. 2) Identify CRISPR sites within the host genome that confer immunity. We will concentrate on host properties by searching for novel restriction enzymes, receptors and CRISPR sites that maybe associated with phage resistance. 3) Evaluate how host lineages impact susceptibility/resistance to phage. We will compare the phages to Mtb host genome sequences among and within well-established lineages to look for patterns of phage interaction. Our findings have the potential to establish a new understanding of phage-host interactions in Mtb. This knowledge will be used to ultimately develop new directions for phage-based therapies to treat drug-resistant tuberculosis.