A color-developing particle indicating microbial growth and its preparation method

Abstract

The invention relates to a color developing particle indicating the growth of microorganisms and a preparation method. The indicator particles of the invention have good stability, high sensitivity and low toxicity to microorganisms.

Description

technical field [0001] The invention belongs to the field of microorganism detection; more specifically, the invention relates to a color-developing particle indicating the growth of microorganisms and a preparation method thereof. Background technique [0002] Clinically, the substrate for pathogenic bacteria to obtain energy is mainly sugar, which releases energy through sugar oxidation or fermentation, and stores energy in the form of high-energy phosphate bonds (ADP, ATP). The types of bacterial biooxidation are divided into respiration and fermentation. During the biochemical process, the hydrogen removed from the nutrients of bacteria (such as sugar) by dehydrogenase needs to be transported by a series of intermediate hydrogen transfer bodies (such as coenzyme I, coenzyme II, flavoprotein, etc.). Finally, the hydrogen is given to the hydrogen acceptor. The biological oxidation process with inorganic substances as hydrogen acceptors is called respiration, in which mol...

AI Technical Summary

Problems solved by technology

[0011] 1. Tetrazolium salt is unstable, sensitive to temperature, humidity and light, and easy to degrade, especially in aqueous solution, it is easy to generate colored products, and its storage solution should not exceed one month even if it is stored in a low temperature (-20°C) environment

The degradation or discoloration of tetrazolium salt greatly reduces the sensitivity of detection. Therefore, it is generally recommended that the tetrazolium salt solution be freshly prepared and used up as soon as possible, which severely limits the use of tetrazolium salt, especially when a certain shelf life is required. Applications in culture, identification, drug sensitivity reagents or products

[0012] 2. In fact, tetrazolium substances are toxic to the growth of bacteria, large or small. Studies have shown that when the TTC content of tetrazolium salt is 0.005%, the red indicator effect of Gram-negative bacteria is the best, and it has the best effect on bacteria. It is also small, but it has a strong inhibitory effect on most Gram-positive bacteria (such as mycobacteria, etc.). If the concentration is lowered, it will not be effective in indicating positive bacteria.

For example, if TTC is used as an indicator for food microbial colony counting determination, unqualified food with excessive microorganisms may be misjudged as qualified food

[0013] 3. It cannot be added to the medium of some slow-growing bacteria (such as mycobacteria, fungi, etc.) in advance to indicate their growth, especially Mycobacterium tuberculosis

[0014] It should be said that tetrazoles have been widely used in cell culture and the cultivation, identification and drug sensitivity of fast-growing bacteria, but they are limited in the use of mycobacteria, especially Mycobacterium tuberculosis. The reasons are: (1) tuberculosis classification The nutritional conditions required for the growth of mycobacteria are very harsh, and they are more sensitive to tetrazole substances. If the added amount is large, it will inhibit its growth, and if it is small, it will not see the change of color; (2) Mycobacterium tuberculosis grows extremely slowly (breeding one generation The cycle takes 18-20 hours), on the one hand, the energy metabolism is very low, and when there is only a small amount of bacteria in the initial growth period, the indicator cannot be restored to color at all.

On the other hand, the tetrazolium salt in the culture medium is easily degraded when cultured at 37°C for several days, more than ten days or even twenty days, which reduces the indicator ability of the tetrazolium salt.

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