Mechanisms of resistance refer to the various ways that organisms, particularly bacteria, develop the ability to withstand the effects of harmful agents, such as antibiotics. These mechanisms can include genetic mutations, which alter the target sites of drugs, or the acquisition of resistance genes from other bacteria through processes like horizontal gene transfer. Additionally, some bacteria can produce enzymes that inactivate antibiotics, while others may develop efflux pumps that expel the drugs before they can take effect. Understanding these mechanisms is crucial for developing new treatments and combating the growing issue of antibiotic resistance.