Selama, a junior studying Biology at Howard University, characterizes an unknown protein in Clostridioides difficile.
In 2019 alone, there were an estimated 5 million global deaths from resistant bacterial infections. However, many low- and middle-income countries (LMICs) cannot diagnose these severe diseases. Therefore, diagnostic assays that are cost-effective and field-deployable are urgently needed to fight bacterial infections in LMICs. SHERLOCK (Specific High Sensitivity Enzymatic Reporter UnLOCKing) is a Cas13-based nucleic acid detection platform that combines isothermal pre-amplification with Cas13 to detect nucleic acid targets. It can be used in either colorimetric lateral flow or fluorescence-based readout systems and detect bacterial species causing infections and antimicrobial resistance (AMR) genes. In this project, we are building a low-cost assay that detects bacterial species and AMR gene content, meeting this global unmet need. At Broad, I got a glimpse of what it is like to be a bridge from the bench to the bedside while working with a physician and physician-scientist. My project intensified my desire to advance infectious disease treatment and research in underserved communities. I thank my PI, mentor, and lab members for welcoming and supporting me. I am also grateful for the opportunity and the BSRP staff for guiding me. The six major genetic drivers of carbapenem resistance and the seven most common causative species of gram-negative bacteremia were selected for inclusion in the assay. Recombinase Polymerase Amplification (RPA) primers were designed to isothermally amplify the topA gene, a highly conserved gene with sequences specific to each bacterial species of interest. RPA and SHERLOCK reagents using a fluorescence readout were combined in a one-pot reaction to streamline the workflow. To date, the assay can detect 4/7 intended species and 4/6 AMR gene targets, and it was validated on a large sample set of 100 strains. This assay has the potential to be implemented almost anywhere in the world to enable effective, rapid diagnosis of bacterial infections.
Project: Development of an Inexpensive Portable Assay to Rapidly Profile Resistant Bacterial Infections
Mentor: David Roach
PI: Bhattacharyya Lab