Table 1.
Characteristic | Genetic AMR | Phenotypic AMR |
---|---|---|
Resistance directly attributable to a genetic change (de novo mutation or acquisition of new genes) | Yes | No |
Resistance manifest in progeny of the resistant bacterial cells | Yes | No or limited |
MIC, relative to sensitive strain | Increased | Unchanged |
MBC, relative to sensitive strain | Increased | Increased under some circumstances |
Clinical outcome | Primary treatment failure | Primary treatment failure |
Relapse | ||
Emergence of genetic AMR | ||
Clinical strategy | Switch antibiotics | Combine antibiotics |
Include antibiotics that kill bacteria expressing phenotypic AMR to conventional antibiotics | ||
Increase treatment time |
MIC, minimum inhibitory concentration, the lowest concentration of the antibiotic required to prevent growth of the bacteria over a defined period of time; MBC, minimum bactericidal concentration, the lowest concentration of the antibiotic that kills a given proportion of the population (typically 99%) in a given period of time; AMR, antimicrobial resistance.