Microbial Mutations - Accumulation in Microfluidics and Collateral Sensitivity

Mutations are a primary source of genetic variation and a major driving force in evolution by influencing survivability (fitness), genetic disease, and the development of complex traits such as antibiotic resistance. However, studying the mutation process is extremely challenging and time consuming, as most mutation rates lie between 1×10-11 to 1×10-9 mutations per site per generation. In my work, we have developed two major improvements in how we study the mutation process. First, we have developed a closed-system microfluidic platform that can be used to efficiently and rapidly measure mutation rates. This liquid-based platform overcomes many limitations of traditional growth methods, and can allow for the study of extremophiles or pathogens that cannot be grown on solid media. Second, we are studying mutations that drive collateral sensitivity (resistance from one antibiotic giving rise to sensitivity from another antibiotic) within Burkholderia multivorans patient isolates. Across 8 lineages involving 6 antibiotics, we identify mutations in Chemoreceptor CheD, DNA ligase D, and BON domain-containing proteins that are associated with antibiotic sensitivity. These proteins are known to repair double-stranded DNA breaks and control efflux pump function, providing a mechanistic approach for combatting antibiotic resistant strains using gene therapy.