resistance

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resistance

medicine

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July 13, 2026

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Drug resistance is when a disease-causing organism can withstand drug therapy. In any population of infectious agents, some may have a mutation that allows them to resist a drug. When the drug kills off the nonresistant microbes, the resistant ones multiply. This is more likely if drugs are not taken correctly, such as not completing a course of antibiotics, or if they are prescribed improperly. Overprescription and the use of antibiotics in animal feed have accelerated the evolution of resistant strains, making infections harder to treat.1

Bacteria can develop resistance through genetic mechanisms like mutation or by acquiring new genetic material. These mechanisms alter bacterial cell properties, making them less susceptible to drugs. Resistance can also occur in cancer cells, preventing them from responding to chemotherapy.23

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plant disease
Host resistance and selection
Disease-resistant varieties of plants offer an effective, safe, and relatively inexpensive method of control for many crop diseases. Most available commercial varieties of crop plants bear resistance to at least one, and often several, pathogens. Resistant or immune varieties are critically important…
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Disease-resistant varieties of plants offer an effective, safe, and relatively inexpensive method of control for many crop diseases. Most available commercial varieties of crop plants bear resistance to at least one, and often several, pathogens. Resistant or immune varieties are critically important…
Read More

community ecology
Gene-for-gene coevolution
…a mutated gene, dubbed the resistance gene in this scenario, that allows them to detect a substance the parasite emits, encoded by a so-called avirulence gene. After being alerted to the threat of the parasite, the host responds to prevent the parasite from invading. The resistance gene will confer an…
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…a mutated gene, dubbed the resistance gene in this scenario, that allows them to detect a substance the parasite emits, encoded by a so-called avirulence gene. After being alerted to the threat of the parasite, the host responds to prevent the parasite from invading. The resistance gene will confer an…
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disease
Host resistance
The specificity of pathogenic microorganisms with regard to their hosts is an expression not only of differences in microbial character but also of differing host resistance. The ability of a microorganism to produce disease can be evaluated only in terms of the host reaction,…
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The specificity of pathogenic microorganisms with regard to their hosts is an expression not only of differences in microbial character but also of differing host resistance. The ability of a microorganism to produce disease can be evaluated only in terms of the host reaction,…
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tetracycline
…of the intestine can become resistant to tetracyclines, resulting in overgrowth (suprainfection) of resistant organisms. The widespread use of tetracyclines is thought to have contributed to an increase in the number of tetracycline-resistant organisms, in turn rendering certain infections more resilient to treatment. The use of tetracyclines in livestock feed…
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…of the intestine can become resistant to tetracyclines, resulting in overgrowth (suprainfection) of resistant organisms. The widespread use of tetracyclines is thought to have contributed to an increase in the number of tetracycline-resistant organisms, in turn rendering certain infections more resilient to treatment. The use of tetracyclines in livestock feed…
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