Drug resistance is the reduction in effectiveness of a drug such as an antimicrobial or an antineoplastic in curing a disease or condition. When the drug is not intended to kill or inhibit a pathogen, then the term is equivalent to dosage failure or drug tolerance. More commonly, the term is used in the context of resistance that pathogens have "acquired", that is, resistance has evolved. When an organism is resistant to more than one drug, it is said to be multidrug-resistant. In a broad sense the immune system of an organism is such a drug delivery system, albeit autonomous, and faces the same arms race problems as external drug delivery.
The development of antibiotic resistance in particular stems from the drugs targeting only specific bacterial proteins. Because the drug is so specific, any mutation in these proteins will interfere with or negate its destructive effect, resulting in antibiotic resistance.
Bacteria are capable of not only altering the enzyme targeted by antibiotics, but also by the use of enzymes to modify the antibiotic itself and thus neutralise it. Examples of target-altering pathogens are Staphylococcus aureus, vancomycin-resistant enterococci and macrolide-resistant Streptococcus, while examples of antibiotic-modifying microbes are Pseudomonas aeruginosa and aminoglycoside-resistant Acinetobacter baumannii.
Resistance to chemicals is only one aspect of the problem, another being resistance to physical factors such as temperature, pressure, sound, radiation and magnetism, and not discussed in this article, but found at Physical factors affecting microbial life.
Read more about Drug Resistance: Introduction, Mechanisms, Metabolic Price, Treatment
Famous quotes containing the words drug and/or resistance:
“Behind the steering wheel
The boy took out his own forehead.
His girlfriend’s head was a green bag
Of narcissus stems. “OK you win
But meet me anyway at Cohen’s Drug Store
In 22 minutes.””
—John Ashbery (b. 1927)
“How is freedom measured, in individuals as in nations? By the resistance which has to be overcome, by the effort it costs to stay aloft. One would have to seek the highest type of free man where the greatest resistance is constantly being overcome: five steps from tyranny, near the threshold of the danger of servitude.”
—Friedrich Nietzsche (1844–1900)