Susceptibility testing - Phenotypic and genotypic tests for bacteria and mycobacteria

Detection of antimicrobial resistance is important to allow clinicians to select appropriate antimicrobial therapy when treating infections. This article reviews the role of the clinical microbiology laboratory in providing antimicrobial susceptibility testing and the principles of conventional (phenotypic) and newer molecular (genotypic) antimicrobial susceptibility testing for bacteria and mycobacteria. As genetic mechanisms of antimicrobial resistance become defined further, clinicians need to understand the potential applications and limitations of molecular methods for the detection of antimicrobial resistance.