Over the past two decades, the international community has successfully developed a technology that can detect multiple reactions or dozens of reactions in a single test, so that microorganisms can be quickly and easily identified, which is known as multiple trace simple identification technology, or simple diagnostic technology, or digital classification and identification method. Multiple trace simple identification technology has been widely used in animal and plant quarantine, food hygiene, environmental protection, drug testing, fermentation control, ecological research, etc., especially in clinical testing is very popular and rapid development. Internationally, there are many kinds of products, or systems, of this technology, domestically, there are Enterobacteriaceae bacterial identification card E-15 of Henan Kaifeng Institute of Medical Biology; Shanghai Municipal Sanitary and Epidemiological Station's fermentation Gram-negative bacilli identification system SWF-A; China's entry into the People's Liberation Army, the 181 Hospital's anaerobic rapid biochemical identification of the series of ARB-ID; Enterobacteriaceae bacterial identification card ENT of Shenzhen Huashida Bio-technology Co. Ltd. of Enterobacteriaceae, ENT biochemical identification card, etc. The foreign products have been standardized and systematized. Foreign products have been standardized, systematized and commercialized, mainly including API/ATB of France Bio-Mérieux Group, Micro-ID, Entemtube, Minitelk of Switzerland Roche, fully automatic and manual bacterial identification system of Biolog of the United States, and rapid identification plate of E. coli in water of Japan, etc., among which API/ATB includes many identification systems, with a total of 750 reactions. The API/ATB includes many identification systems, a total of 750 kinds of reaction, can identify almost all the bacteria + a number of micro-simple identification technology has outstanding advantages, not only can fast, sensitive, accurate, repeatable identification of microorganisms, and simple, save into the force, material resources, time and space, the disadvantage is that the system varies greatly, some expensive, some individual reaction is not allowed, difficult to determine, but there is no doubt that it is microbiology technology to rapid, simple and automated development of important methods. However, there is no doubt that it is one of the important directions for the development of microbiological technical methods towards rapidity, simplicity and automation. Source: Experiments in Microbiology (Third Edition)
Operation method
basic program
Principle
The API 20E system is the earliest and most important product of the API/ATB and the most used system internationally, and it is used in this experiment to test bacteria. The identification card of this system is a piece of plastic strip with 20 compartments, the compartments are composed of connected tubes and rings, each tube contains different dehydrated media, reagents, or substrates, etc. Each compartment can carry out one biochemical reaction, and individual compartments can carry out two reactions, which is mainly used for the identification of Enterobacteriaceae as shown in Fig. 1. Figure 1 API 20E identification card
Materials and Instruments
Purified strains of Enterobacteriaceae to be tested Move 1. Prepare the single or multiple colonies to be tested to 150 million or greater in sterile water and mix well. 2. Remove the sealing film from the API 20E identification card and label the card with the number of organisms to be tested, the date, and the person who performed the test. 3. Use a sterile capillary tube to aspirate the prepared bacterial solution and slowly add it to the tubes at a slight incline along the inner wall of the tubes in the separation chamber to fill the tubes, as well as the cups with a boxed line for the test name on the identification card, and the cups with a horizontal line under the test name, to fill with liquid paraffin. Avoid the formation of air bubbles when adding liquid, if air bubbles are formed, shake gently to remove them, and do not remove air bubbles with a capillary tube that sucks up bacterial liquid. 4. Place the inoculated identification cards into a plastic box or shallow ceramic plate with a small amount of water (to prevent evaporation of the reaction solution), and incubate at 37 ℃. 5. 5. Incubate for 18 to 24 h, and then add the specified reagents to the small cups where the reagents are to be added, such as adding IND reagent for IND reaction and V.P. reagent for V.P. reaction. Observe the color change of each reaction on the identification card and determine whether the reaction is positive or negative according to the reaction determination table (Table 1). 6. 6. According to the order of the reaction items on the identification card, every three reaction items are organized into one group, and there are seven groups in total. Each reaction item in each group is designated as a numerical value, in order of 1, 2 and 4, and those with positive reactions in each group are marked as "+", and their designated values are written down, while those with negative reactions are marked as "-", and their values are written down as 0. The numerical values of each group are added up and are the coded number of the group, and a 7-digit coding is thus formed. This results in a 7-digit code, which is illustrated in Table 2. 7. 7. The 7-digit code can be searched on a search form or entered into a computer. The 7-digit code can be used to look up a search form or entered into a computer to identify the strain of bacteria being tested. For more product details, please visit Aladdin Scientific website.
Sterile water
API 20E system Liquid paraffin Sterilized capillary burette