Resistance to antimicrobials can develop through several genetic mechanisms.
The main mechanisms of resistance are: inactivation of a drug, reduced uptake of a drug, active efflux of a drug and modification of a drug target.
An overview of the antimicrobial resistance mechanisms of bacteria (AIMS Microbiology, 2018)
Antibiotic resistance mechanisms in bacteria: relationships between resistance determinants of antibiotic producers, environmental bacteria, and clinical pathogens (Frontiers in Microbiology, 2018)
Evolutionary pathways and trajectories in antibiotic resistance (Clinical Microbiology Reviews, 2021)