drug resistance

(redirected from Drug resistant)
Also found in: Encyclopedia, Wikipedia.

resistance

 [re-zis´tans]
1. opposition, or counteracting force, as opposition of a conductor to passage of electricity or other energy or substance.
2. the natural ability of a normal organism to remain unaffected by noxious agents in its environment; see also immunity.
3. in psychology or psychiatry, conscious or unconscious defenses against change, preventing repressed material from coming into awareness; they can take such forms as forgetfulness, evasions, embarrassment, mental blocks, denial, anger, superficial talk, intellectualization, or intensification of symptoms. It occurs because the blocked association or understanding would be too threatening to face at this point in the therapy; identification of what point the resistance comes at can be an important indicator of the patient's unconscious patterns.
airway resistance the opposition of the tissues of the air passages to air flow: the mouth-to-alveoli pressure difference divided by the rate of air flow. Symbol RA or RAW.
androgen resistance resistance of target organs to the action of androgens, resulting in any of a spectrum of defects from a normal male phenotype in which men have normal genitalia but infertility to complete androgen resistance in which the individual has a female phenotype. Complete androgen resistance is an extreme form of male pseudohermaphroditism in which the individual is phenotypically female but is of XY chromosomal sex; there may be rudimentary uterus and tubes, but the gonads are typically testes, which may be abdominal or inguinal in position. Called also testicular feminization and testicular feminization syndrome. Incomplete androgen resistance is any of various forms less than the complete type, manifested by a male phenotype with various degrees of ambiguous genitalia such as hypospadias and a small vaginal pouch, a hooded phallus, or a bifid scrotum that may or may not contain gonads.
drug resistance the ability of a microorganism to withstand the effects of a drug that are lethal to most members of its species.
insulin resistance see insulin resistance.
multidrug resistance (multiple drug resistance) a phenomenon seen in some malignant cell lines: cells that have developed natural resistance to a single cytotoxic compound are also resistant to structurally unrelated chemotherapy agents. Called also cross-resistance.
peripheral resistance resistance to the passage of blood through the small blood vessels, especially the arterioles.
pulmonary vascular resistance the vascular resistance of the pulmonary circulation; the difference between the mean pulmonary arterial pressure and the left atrial filling pressure divided by the cardiac output. Called also total pulmonary vascular resistance.
total peripheral resistance the vascular resistance of the systemic circulation: the difference between the mean arterial pressure and central venous pressure divided by the cardiac output.
total pulmonary resistance (total pulmonary vascular resistance) pulmonary vascular resistance.
vascular resistance the opposition to blood flow in a vascular bed; the pressure drop across the bed divided by the blood flow, conventionally expressed in peripheral resistance units. Symbol R or R.

drug re·sis·tance

the capacity of disease-causing microorganisms to withstand exposure to drugs previously toxic to them; acquired either through spontaneous mutation or by gradual selection of relatively resistant strains after drug exposure. Pathogenic microorganisms resist antibiotics by various mechanisms, including the production of enzymes (for example, β-lactamases) that chemically inactivate antibiotic molecules. In mixed infections of the respiratory tract, a β-lactamase (penicillinase) produced by one organism (for example, Haemophilus influenzae) can inactivate penicillin and so block its effectiveness against other organisms in the mixture that possess no resistance of their own (for example, group A β-hemolytic streptococci). Usually an organism that has acquired resistance to a given antibiotic is resistant to others in the same chemical class. Some bacteria transmit antibiotic resistance to their offspring not chromosomally but via plasmids, which lie outside the bacterial nucleus but perform certain genetic functions. Bacteria of one species can develop resistance to certain antibiotics by acquiring plasmids from bacteria of another species.

Drug resistance is a growing problem worldwide. Many strains of bacteria, fungi, and parasites have developed resistance, including pneumococci, gonococci, salmonellae, Mycobacterium tuberculosis, Tinea tonsurans, and Plasmodium falciparum. In some parts of the U.S., 40% of pneumococcal isolates and 90% of staphylococci are resistant to penicillin. The prevalence of both vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus has increased 20-fold during the past decade. Resistance of gram-positive pathogens, including Streptococcus pneumoniae and group A β-hemolytic streptococci, to macrolide antibiotics has also increased rapidly. Widespread use of fluoroquinolones for respiratory and urinary tract infections has led to a steady decline in the susceptibility of aerobic gram-negative bacilli, particularly Pseudomonas aeruginosa, to these agents. Factors favoring development of drug resistance include inappropriate prescribing of antibiotics (for example, for viral infections); indiscriminate use of newly developed, extended-spectrum agents; irrational use of broad-spectrum antibiotics to treat β-hemolytic streptococcal infections; empiric prescribing of broad-spectrum agents for infections in certain populations (for example, children, the elderly, and residents of long-term care facilities); prescribing of sublethal and thus ineffective dosages; and failure of patients to complete courses of antibiotic treatment. Antimicrobial treatment that is begun empirically before results of cultures and sensitivity tests are available and does not include agents that are effective against resistant strains of organisms, increases morbidity and mortality. Infectious disease experts and public health authorities have called for restraint by primary care physicians in prescribing antibiotics, particularly in children and for uncomplicated upper respiratory infections, acute bronchitis (nearly always viral), and acute sinusitis and otitis media (in neither of which have reliable diagnostic criteria for bacterial infection been established). They have also stressed the importance of public education, because inappropriate expectations of patients or their parents have been a driving factor in antibiotic overuse by physicians. Administration of antibiotics to livestock animals, chiefly for disease prophylaxis and growth promotion, has also contributed to the emergence of resistant strains of bacteria.

drug resistance

the ability of disease organisms to resist effects of drugs that previously were toxic to them. Bacterial resistance to an antibiotic can result from mutation of a strain that has been exposed to an antibiotic or similar agent. Such acquired resistance may result from a chromosomal disruption or acquisition of a stray bit of deoxyribonucleic acid (DNA) on a resistant plasmid. It can also be caused by extrachromosomal pieces of DNA that carry codes for antibiotic-resistant genes from a transposon, a DNA segment capable of insertion into a bacterial chromosome-resistant plasmid, or both. Decreased permeability to an antimicrobial is a common form of intrinsic resistance. Alteration or inactivation of the antibiotic is perhaps the most common mechanism of drug resistance. Acquired resistance to beta-lactam antibiotics is determined by the production of enzymes that inactivate the antibiotic. Drug resistance may also result from a change in the target site on which it acts.

drug resistance

The ability of bacteria and other microorganisms to withstand a drug to which they were once sensitive

drug re·sis·tance

(drŭg rĕ-zis'tăns)
The capacity of disease-causing pathogens to withstand drugs previously toxic to them; achieved by spontaneous mutation or through selective pressure after exposure to the drug in question.

drug re·sis·tance

(drŭg rĕ-zis'tăns)
Capacity of disease-causing microorganisms to withstand exposure to drugs previously toxic to them.

drug

1. any medicinal substance.
2. a narcotic.
3. to administer a drug.

drug administration
includes aerosol, oral, transtracheal infusion, subcutaneous, intramuscular, intravenous, intrauterine, intraperitoneal, intra-articular, intramammary, intrathecal, subconjunctival, percutaneous, percutaneous intraruminal, gas inhalation. Mass medication is per feed or drinking water or, in the case of captive fish, in the tank water. For feral animals individual dosing by projectile dart is usual, for group therapy administration by bait is possible.
drug allergy
immune-mediated hypersensitivity to a drug molecule. Includes anaphylaxis, cutaneous reaction.
animal drug
a drug specifically tested for, and recommended for use in, animals. A legal point of importance if an animal dies as a result of an unusual or allergic reaction to medication with a drug not licensed for use in animals.
drug augmented swine dysentery
pigs receiving prophylactic medication are more severely affected than untreated pigs.
bactericidal/bacteriostatic drug
drug binding
binding of a drug to a large molecule in the tissues or fluids, e.g. binding to protein in the blood, may affect the metabolism of the drug, especially its rate of excretion.
chemotherapeutic drug
drug combinations
a pharmaceutical strategy of combining several drugs into one formulation to provide for a specific requirement, e.g. an antibiotic combined with an anti-inflammatory agent in a mastitis ointment. Has the disadvantage that the dose of one drug is determined by the dose of the other.
controlled drug
availability and use of the drug is controlled by law. The control is at various levels of severity depending on the degree of danger associated with the uncontrolled use of each drug.
drug delayed swine dysentery
swine dysentery appears several days after treatment is discontinued.
drug delayed-augmented swine dysentery
after successful treatment during an attack of swine dysentery a more severe form of the disease occurs after treatment ceases.
drug diminished swine dysentery
the disease is reduced in severity as a result of treatment but is not eliminated.
drug eruption
an eruption or solitary skin lesion caused by a drug. See also dermatitis medicamentosa.
drug hypersensitivity
see drug allergy (above).
mutagenic d's
those that affect the DNA of the target organism have the hazard of creating new races of microorganisms with increased pathogenicity.
drug residue
the amount of the drug that can be detected in tissues at specified times after administration of the drug ceases. See also drug tolerance (below).
drug resistance
said mainly of antibacterial drugs and of microorganisms that are unaffected by the drug whilst most organisms of its species are susceptible. The resistance may be inherent or secondary to frequent exposure at sublethal levels. Resistance of an animal to a specific drug, e.g. to insulin, can also occur in this way.
drug resistant swine dysentery
medication of the feed is not an effective procedure and diarrhea and deaths occur.
drug safety margin
the magnitude of the difference between the dose required to produce a maximum therapeutic effect and that which produces a toxic effect. Registering authorities require this information.
drug selectivity
capacity to produce a single effect.
teratogenic drug
produces a toxic effect on the fetus at a particular phase of development producing a malformation.

resistance

1. opposition, or counteracting force, as opposition of a conductor to passage of electricity or other energy or substance.
2. the natural ability of a normal organism to remain unaffected by noxious agents in its environment. See also immunity.
3. acquired ability of a bacterium or helminth or arthropod parasite to survive in the presence of concentrations of a chemical which are normally lethal to the organisms of that species. Occurs usually as a result of prolonged growth of the organism in sublethal concentrations of the agent and the survival of the organisms which have the least innate susceptibility to the agent. Has serious implications for animals which may find themselves without a suitable remedy for a disease, and for humans who may experience transfer of a resistant organism from the food supply.
4. in studies of respiration, an expression of the opposition to flow of air produced by the tissues of the air passages, in terms of pressure per amount of air per unit of time.

drug resistance
the ability of a microorganism to withstand doses of a drug that are lethal to most members of its species.
peripheral resistance
resistance to the passage of blood through the small blood vessels, especially the arterioles.
transferable resistance
antimicrobial resistance genes carried by bacteria on plasmids or transposons can often be readily acquired by other strains of the same species, by different species, and sometimes by organisms in different genera. Of considerable import in consideration of the implications of antimicrobial therapy in animal populations and in public health. The full significance is difficult to ascertain.
References in periodicals archive ?
When those suffering from multi- drug resistant TB are not treated properly, they develop the extensively resistant form of TB.
There is also concern about extensively drug resistant tuberculosis, which is resistant to the back-up drugs as well.
Dr Paul Cosford, executive director of health protection services at the HPA, said: "Although drug resistant and multi-drug resistant cases of infection represent only a small proportion of TB cases overall, each resistant case requires careful and often prolonged treatment and care.
And Dr Mario Raviglione, of the World Health Organisation, found that the multi-drug resistant TB can lead to a more severe strain called extensive drug resistant TB, seen in HIV patients in South Africa.
Illegal aliens have been found to be the confirmed source of outbreaks of drug resistant strains of TB, malaria (once effectively wiped out in the U.
We are identifying agents that appear to work effectively to kill drug resistant breast tumour cells," Parissenti says.
The experiments were the first to find the virus hidden in the immune system in patients with undetectable levels of HIV in their blood, and the first to show that the virus did not become drug resistant in people who were responding well to combination therapy.
In a poster presentation at the meeting, entitled, "Second Generation of Covalent Irreversible Inhibitors Have Superior Potency Across Genotypes and Drug Resistant Mutants," data were presented from preclinical studies that evaluated the efficacy of AVL-192 in biochemical and cell culture studies.
Drug resistant TB (DR-TB) infections are also on the rise in India.
THE treatment of drug resistant tuberculosis ( TB) may become easier as a new drug regimen promises to cure infection in nine months -- a drastic reduction from the current two years.
P2 is designed to examine whether new drug resistant strains of HTV - 1 can be sexually transmitted between partners who are already both HIV-positive (superinfection).
Efflux-pump inhibitors might also make some microbes that are intrinsically drug resistant vulnerable to antibiotics, he says.