Antibacterial spectrum of antibacterial drugs

Antibacterial spectrum of antibacterial drugs
Antimicrobial spectrum is the range of varieties of bacteria that are sensitive to the drug. Due to the diversity of its physical and chemical properties, the mechanism of its effect on the bacteria is also different. Some are interfering with bacterial cell wall synthesis, some of the damage of bacterial cell membrane, some of which affect the synthesis of bacterial cell proteins or nucleic acids, which lead to drug sensitive bacteria in the range of different drug. So different drugs have different antibacterial spectrum, some drugs are mainly gram positive bacteria (according to Gram stain reaction, can be divided into gram positive bacteria and gram negative bacteria) sensitive, some drugs are sensitive to gram negative bacteria, but also some of the drug gram positive bacteria and gram negative bacteria are sensitive. The two class is called as antibacterial agents, which is referred to as a broad-spectrum antibiotic. The range of different drugs among different drugs is different. The gram negative bacteria were more sensitive to the drug than gram positive bacteria. Fish pathogenic bacteria is gram negative bacteria, so the use of antibiotics in aquaculture is the majority of broad-spectrum antibacterial drugs.
Drug residues and drug withdrawal period
After drugs into the body, to experience from the absorption, distribution, metabolism, and so on a series of processes, and finally discharged from the body. These processes are in need of a certain period of time, and the length of time is mainly related to the physical and chemical properties of drugs and the variety of animals. The drug is completely eliminated from the fish, some only a few days, while others demand for several months. The residual amount is the content of the drug in the body of the fish market. The content may be very low, but when the human body long-term intake of residual drug, the drug is likely to accumulate in the human body, and then the human body to produce toxic and promote the human body to produce drug resistance. To this end, many countries have used the drug for the approval of the withdrawal period. That is to say, if the use of a certain kind of medicine, the need to stop the medicine for a period of time after the sale, so that the fish in the amount of drug residues to reach the maximum allowable concentration of the following. China has this kind of rules (the people’s Republic of China Ministry of agriculture Announcement No. 235), especially the aquatic products export enterprises in this regard problems must be paid attention to, otherwise it will seriously affect the export of aquatic products, the problems in the export of Japanese eel (Anguilla japonica) had precedent. Even more important is the residue of the drug will seriously affect the health of the vast number of consumers in Ankang.

Several important concepts

Several important concepts
1, drug formulation and preparation
Dosage form is a kind of form that can be processed and modulated, easy to use, save and transport. The dosage form can be divided into liquid, gas, solid, semi solid. Preparation is an individual dosage form of a drug.
2 local effect and absorption
The function of the drug is divided into local and absorptive function. The former is the drug to be absorbed into the blood before the play the role of, such as topical disinfectant on the surface of bacteria killing effect and dipterex of Lernaea ‘”absorption refers to the drug is absorbed into the blood after the play the role of, such as chloramphenicol for furuncle hysteria and ulcer disease. The role of the absorption is extensive, which can be involved in all parts of the body. However, due to the different physical and chemical properties, the distribution of them is not the same as in vivo residence time (or in vivo process). For example, after oral absorption, the part of the body is damaged, and the rest are excreted in the urine, and the drug concentration in urine can be used for sensitive storage. Therefore, different drugs have different indications and effects, should be understood in detail.
3 direct and indirect effects
The direct effect is that the function or form of the function of the object is changed. The indirect effect is the secondary function of the body fluid regulation. The bactericidal or antibacterial effect of the antibacterial drugs is the direct action of the drugs in the aquatic drugs play an indirect role in the drug less.
4 synergistic and antagonistic effects
When two or more drugs used in combination, the role can be strengthened due to compensate each other, can be cancelled or reduced, the former synergistic effect, which is called the twist resistance and dispensing can be using the synergistic effects of other drugs, to strengthen the main drug therapy, and should pay attention to avoid the role of anti Chu. But sometimes in order to offset the side by using bamboo Weiyao other drugs Hangzhou antagonistic effect
With the further study of the mechanism of drug action, the antibacterial drugs can be divided into four categories: 1. 2, stationary or slow acting bactericidal agent, streptomycin, card the kanamycin, gentamicin, 3, fast efficient antibacterial agent, chloramphenicol, erythromycin, tetracycline. 4, slow acting agent — sulfa drugs.
This classification has certain directive significance to the application of antibacterial drugs. The combination of the first and the second drugs can produce a synergistic effect, which is due to the destruction of the integrity of the cell wall, and the second type of drug is readily available in the cell. The third drugs can quickly block the synthesis of proteins, so that the bacteria are still in a state of rest, and therefore, when the first type of combination of the latter may lead to the weakening of the latter activity. Third types and second kinds of combination, often can get the cumulative or synergistic effect, generally does not have an antagonistic phenomenon. While the third category of the first class of antibacterial activity without significant influence, and sometimes can produce cumulative effect, similar drugs can also be used in combination.
With the small amount of disinfectant solution containing chlorine or bromine, iodine can greatly enhance the bactericidal ability. There are some substances have synergistic effect on chlorine containing disinfectant.