Abstract

Rapid Sample to Answer Antibiotic Susceptibility Testing for Bacteremia

Alexis Sauer-Budge, Senior Research Scientist And Adjunct Research Assistant Professor, Fraunhofer CMI @ Boston University

Disease causing microbes that have become resistant to drug therapy are an increasing public health problem. Factors contributing to the rise in antibiotic resistance include widespread and inappropriate prescription of broad-spectrum antibiotics and patient non-compliance to antibiotic regimens.  Bloodstream infections, which can lead to sepsis are of particular concern as they represent a serious and growing health burden (9% of all deaths in the US). Despite exhaustive research and development into rapid diagnostics, the leading technologies still require significant time from blood draw to susceptibility results.  The major challenge of diagnosing blood-borne pathogens and prescribing the appropriate antibiotic is that the microbes are present in low concentrations in blood (often 10 CFU/mL).  Hence, amplification and isolation of the pathogens prior to drug susceptibility testing is required.  This talk will describe a novel and rapid sample preparation methodology that efficiently isolates microorganisms directly from whole blood and entirely circumvents the need for traditional blood culture.  The process takes about 30 min and maintains the viability of the pathogens for downstream live processing while reducing the 10 mL blood sample into a less than 30 µL volume.  Additionally, we have developed a microfluidic platform with which we have shown that shear stress can cause irreparable damage to susceptible but not resistant strains.  Thus, we are able to accurately assign antibiotic susceptibility profiles without waiting for bacterial growth (entire assay 1-2.5 h depending on the antibiotic tested).