Drug resistance, also known as drug resistance, refers to the tolerance of microorganisms, parasites and tumor cells to the effects of chemotherapy drugs. Once drug resistance occurs, the chemotherapy effect of drugs will significantly decline.Drug resistance can be divided into acquired drug resistance and natural drug resistance according to its causes.Pathogens in nature, such as a certain strain of bacteria, can also have natural resistance.When antibiotics are used for a long time, the majority of sensitive strains are constantly killed, and the drug-resistant strains multiply in large numbers to replace the sensitive strains, which makes the resistance rate of bacteria to the drug continuously increase.At present, it is believed that the latter is the main reason for producing drug-resistant bacteria.In order to maintain the effectiveness of antibiotics, we should pay attention to their rational use.
There are two kinds of inactivating enzymes, one ishydrolase, such as β - lactamase can hydrolyzepenicillinOr cephalosporins.The enzyme may be composed of chromosomes orplasmidMediated, the production of some enzymes is constitutional (histone enzyme);Some can be induced（Inducible enzyme）。SecondInactivating enzymeSynthase, also known as synthetase, can catalyze the binding of certain groups to the OH or NH2 group of antibiotics to inactivate antibiotics.Most of them are resistant to aminoglycoside antibioticsGramNegative bacilli can produce plasmid mediated inactivating enzymes, such as acetylTransferasesActing on NH2 base,PhosphotransferaseAnd nucleoside transferase act on OH group.The above enzymes are located inCytoplasmic membraneOuter space, aminoglycosides areEnzyme inactivationIt is not easy to interact withRibosomeBinding, which leads to drug resistance.
Change the permeability of bacterial plasma membrane
Bacteria can prevent antibiotics from entering bacteria through various ways, such asGramCells of negative bacilliadventitiayespenicillinG has natural barrier function;Pseudomonas aeruginosaAnd other gram-negative bacillicell wallWaterhole, or changes in the function of non-specific channels in the outer membrane, causing bacteria resistance to some broad-spectrum penicillin, cephalosporins, including some third-generation cephalosporins;The resistance of bacteria to tetracycline is mainly due to the resistanceplasmidIt can induce the production of three new proteins, blocking the water holes in the cell wall, making it impossible for drugs to enter;Gram negative bacilli resistant to aminoglycosidesInactivating enzymeIn addition, due to the change of the water hole in the cell wall, the drug is not easy to penetrate into the bacteria.
Changes of target structure in bacteria
Streptomycin resistanceStrainsBacteria ofRibosome30sSubunitThe P10 protein of streptomycin target changed;LincomycinanderythromycinThe drug resistance of bacteria is caused by the change of the target protein on the 23s subunit of the bacterial ribosome, so that the drug cannot bind to bacteria.someGonococcusyespenicillinG resistance and methicillin resistance of Staphylococcus aureus are due to the change of penicillin binding protein caused by mutation, which makes it difficult for drugs to combine with it.This resistant strain is often resistant to other penicillins and cephalosporins.
other
The resistance of bacteria to sulfonamides can be caused by the increase in the production of PABA, which is antagonistic to drugs, or by changing the resistance of bacteria to sulfonamidesmetaboliteAnd so on.
Difference from drug resistance
Announce
edit
Drug resistance
It refers to the ability of an organism to generate immunity to certain substances in the body so that it cannot harm itself.Drug resistance is the adaptive change of pathogens after long-term exposure to low-dose drugs. Pathogens produce enzymes that inactivate drugs, change membrane permeability to block drug entry, change target structure or change the original metabolic process are all mechanisms of drug resistance.
Drug resistance
Generally, it means that the sensitivity of the pathogen to drugs decreases or even disappears after repeated contact with drugs, resulting in the reduction or invalidity of the efficacy of drugs against the pathogen.Microorganisms, parasites and cancer cells can all produce drug resistance.Drug resistance is the adaptive change of pathogens after long-term exposure to low-dose drugs. Pathogens produce enzymes that inactivate drugs, change membrane permeability to block drug entry, change target structure or change the original metabolic process are all mechanisms of drug resistance.
The difference between the two lies in whether they can harm themselves. The emergence that cannot harm themselves is drug resistance, and the gradual reduction of immunity is drug resistance.
What are the symptoms of drug resistance of hepatitis B
Announce
edit
At present, the commonly used antiviral drugs areNucleoside (acid) analogue, such drugs are generally resistant, and the course of treatment is long, and drug withdrawal is easy to rebound, therefore,Hepatitis B virus resistanceIt is bound to appear in antiviral treatment.Hepatitis B virus resistance includes gene resistance, virological resistance and biochemical resistance.
There is no clinical manifestation of gene resistance,HBV DNAIt is still undetectable, but the mutation of drug resistance gene is found by directly checking the virus gene, such as lamivudine. When we find that MDD immune strain appears, it is considered that drug resistance has occurred;As more and more drug-resistant strains become dominant, there will be hepatitis B virus, and the virus will be positive, which is virological resistance;With the emergence of virological resistance, some transaminases may rebound, which is called biochemical resistance.
Regardless of the drug resistance, the general symptoms are somewhat similar to the symptoms of hepatitis B at ordinary times, such as nausea, vomiting, pain in the liver area, low fever, hair loss, hepatomegaly, and ascites. Because these symptoms are similar to the symptoms of patients at ordinary times, it is difficult to find them.
Nowadays, drug resistance has become a major problem that puzzles the medical community. The production of drug-resistant bacteria is far faster than the development of new drugs, so it is imperative to develop new antibacterial drugs.
