Direct from sample phenotypic antibiotic susceptibility testing

Abstract

To transition from broad-spectrum antibiotic therapy to a more effective "targeted" therapy, i.e. in order to determine whether the infecting strain is resistant or susceptible to individual candidate antibiotics, clinicians and clinical microbiologists need to determine both the pathogen identity (ID) and the Minimum Inhibitory Concentration (MIC) of the candidate antibiotic(s). It is important to note that the pathogen ID or MIC alone is insufficient to yield clinically significant report for patient treatment. Traditionally, tests to determine both the ID and MIC required use of pure bacterial colonies (obtained by plating the patient samples on agar plates) for testing. However, with recent scientific advancement, there are a number of products developed to determine pathogen ID directly from positive patient samples therefore bypassing the need for colony isolation, and delivering results in approximately 6-8 hours after sample collection. However, doing so for the AST remains a challenge, and so improvements in patient outcome have been limited.