DEVELOPMENT OF LOW-COST, MICRO-VOLUME ANTIMICROBIAL RESISTANCE ASSAYS FOR PATHOGENIC BACTERIA

Abstract

A lack of diagnostics and growing antibiotic resistance worldwide threatens to make once treatable disease deadly again. The discovery of antibiotics drastically reduced the mortality of bacterial infectious diseases; however, persistence is still rampant in low- and middle-income countries. Even when infections are properly diagnosed and treatments are available, resistance genes are spreading and leading to more treatment failures. Paper-based diagnostics require no cold chain or power supply and are magnitudes cheaper than standard nucleic acid amplification techniques. They are also easier to perform and run faster than typical cell culture-based diagnostics. Thus, paper diagnostics provide global solutions to curbing bacterial diseases. In this work, I describe efforts to develop low cost, accessible technologies for identifying the presence and the antimicrobial susceptibility profile of various pathogenic bacteria on the World Health Organizations top threat list. Specifically, I focus on Carbapenem-resistant Enterobacterales (CRE), a group of bacteria commonly responsible for hospital acquired infections, and Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea. First, I describe a paper-based chip made of chromatography paper and wax that supports the growth of CRE in the presence of three different clinically relevant antibiotics at three concentrations each. For the low cost of $0.77, this technology can enable personalized antibiotics prescriptions by giving personalized susceptibility information to prescribing clinicians. Next, I describe the evaluation of various colorimetric dyes capable of indicating viability of N. gonorrhoeae. By focusing on dyes that can be seen with the naked eye, we aim to reduce the need for complex equipment and reduce the level of training required for end users. Thirdly, I developed a lateral flow assay to detect the presence of Neisseria gonorrhoeae quickly and accurately in a sample and concentrate and isolate whole, live bacteria that can be used in downstream susceptibility testing. Finally, I combine these technologies to develop a paper chip for antibiotic susceptibility testing of N. gonorrhoeae.