Antibiotic resistance (ABR) is the ability of bacteria and other microorganisms to survive and grow in the presence of an antibiotic that would normally kill them or stop their growth.
Explanation
ABR arises when genetic changes enable microbes to withstand the effects of antimicrobial drugs. These changes may result from spontaneous mutations or from acquiring resistance genes via plasmids, transposons or other mobile genetic elements. Resistance mechanisms include producing enzymes that deactivate the drug, altering the drug’s target site, reducing drug uptake and actively pumping the drug out of the cell. Misuse of antibiotics in medicine and agriculture, such as prescribing them for viral infections or using them as growth promoters, increases selection pressure and accelerates the spread of resistant strains. Resistant infections are harder to treat, often requiring alternative drugs that may be less effective, more toxic or more expensive. Examples of antibiotic‑resistant bacteria include methicillin‑resistant Staphylococcus aureus (MRSA), multidrug‑resistant Mycobacterium tuberculosis, and extended‑spectrum β‑lactamase (ESBL)–producing Escherichia coli and Klebsiella pneumoniae. To combat ABR, strategies such as prudent prescribing, infection prevention, surveillance and development of new antibiotics are essential.
Examples and Issues
Hospital‑associated infections caused by MRSA and vancomycin‑resistant enterococci illustrate how resistant strains can spread in healthcare settings. Drug‑resistant tuberculosis requires lengthy treatment with second‑line drugs. Bacteria in food animals exposed to antibiotics may carry resistance genes that transfer to human pathogens. Laboratories use susceptibility testing to identify resistant isolates and guide therapy. ABR threatens the effectiveness of current treatments and demands coordinated efforts to preserve antibiotic efficacy.