Resistance to antibiotics occurs when bacteria evolve the ability to survive and grow despite exposure to an antibiotic that previously inhibited or killed them. This is often the result of genetic mutations or acquisition of resistance genes.
Explanation
Antibiotic resistance develops when microorganisms are exposed to antimicrobial agents and adapt in ways that neutralize those agents. Antibiotics normally kill bacteria or stop their growth by disrupting key cellular processes, such as cell wall synthesis, protein synthesis or DNA replication. Misuse and overuse of these drugs create selective pressure that favours bacteria with resistance determinants. These determinants can arise from random mutations or through horizontal gene transfer via plasmids and transposons. Resistant organisms may produce enzymes that degrade the drug, modify the antibiotic’s target, or actively efflux the agent from the cell. Inappropriate use – such as taking antibiotics for viral infections, failing to complete prescribed courses or using broad‑spectrum agents unnecessarily – accelerates the evolution and spread of resistance. The rise of resistant pathogens poses a serious public health threat because infections become harder to treat, leading to prolonged illness, higher mortality, and greater healthcare costs.
Real‑world examples and impacts
Clinical examples of antibiotic resistance include methicillin‑resistant Staphylococcus aureus (MRSA), vancomycin‑resistant enterococci (VRE), extended‑spectrum β‑lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae, and multidrug‑resistant Mycobacterium tuberculosis. These organisms have altered or inactivated the targets of β‑lactams, glycopeptides and other agents, or have acquired enzymes that destroy the drugs. Resistance is not limited to hospitals; resistant strains circulate in the community and agricultural settings due to antibiotic use in livestock. The global burden of resistance is significant, contributing to tens of thousands of deaths annually and jeopardising advances in medicine. Stewardship programmes that promote appropriate prescribing, combined with infection control and surveillance, are critical to slow the spread.
Antibiotic resistance underscores the need for continued research into novel antimicrobial agents and vaccines, as well as education on prudent antibiotic use. Without effective measures, common infections could once again become life‑threatening.
Related Terms: Antimicrobial resistance, Beta‑lactamase, Horizontal gene transfer, Multidrug‑resistant organism, Selective pressure