What is bacteriological research? According to what scheme is it carried out? What is meant by safety in this case? What are the goals and stages of bacteriological research?
General information
Bacteriological examination is a scientific process in which bacteria are identified and their properties are studied in order to make a microbiological diagnosis. Of great importance here is the determination of the type or species of the resulting microorganism (pure culture is implied). This is accompanied by the study of the biochemical and physiological properties of organisms, as well as the tendency to toxin formation. For these purposes, precipitation and agglutination reactions are used. It is also practiced to infect laboratory animals with subsequent detection of pathological changes.
Working with test material
The bacteriological study algorithm provides for strict adherence to special instructions. Thus, the test material must be collected in sterile dishes under aseptic conditions. It is also necessary to take care ofto ensure delivery to the laboratory as soon as possible. Cold storage of samples is desirable. The technique of bacteriological research provides for many possible situations. Thus, the type of object, the properties of the microorganism and the nature of the disease often make it necessary to develop individual instructions for work. A large number of different methods are used in the work. One of the most common is bacterioscopy. But if the bacteria are not fixed, then a crushed or hanging drop is used. It should be noted that the last two options are characterized by an increased level of contagiousness.
Bacterioscopy
In this case, strokes are used. To create them, you need to distribute a drop of the liquid that is being studied over the surface of a glass slide. Zates should dry it. This is often done by moving the drug through a flame obtained from a gas burner. Although fixing compounds can be used as an alternative. To indicate that preparatory actions have been carried out with this preparation, it is stained. The purpose of such a manipulation is accuracy, which is very important when microscopic and bacteriological examination is carried out. After all, if you reuse the drug for another purpose, you get porridge, which will be very difficult to work with effectively.
Why bacterioscopy is so popular
Not least due to the availability of this method. If a bacteriological study of a fresh preparation is carried out, then to determine the pathogenmicrochemical reactions or selective staining of various structural parts of the microorganism can be used. Which one is better? A more accurate result can be obtained when working with a colored preparation. In this case, the test material is applied to a pre-prepared glass slide. And be sure to thin (and if possible even) layer. After that, you must wait until the drug dries in the air. The microorganisms are then fixed using one of the conventional methods. After that, the cooled preparation is subjected to staining with a differential or simple paint. For this, dry and native preparations can be used. After that, it remains to direct ultraviolet or short blue rays to the place of accumulation of organisms, which causes the entire microbe or certain parts of its body to glow.
Practical application of bacterioscopy
It is used to diagnose a number of infectious diseases. The most famous of these are tuberculosis, gonorrhea and relapsing fever. In addition, they resort to research in order to study the entire complex of microflora of an organ or product. But critics often point to the relative unreliability and inaccuracy of this method.
Crops and subcultures of bacterial cultures
Carry them out using a Pasteur pipette. Carrying out bacteriological and cytological examination is often difficult to carry out without inoculation and subculture during the workflow. When working with a Pasteur pipette, its tipbreak off with tweezers. The tool itself is then carried through the flame of the burner and then allowed to cool. By the way, both liquid and solid nutrient media can be used for sowing. The choice is influenced by what goals of bacteriological research are pursued. At the same time, it is necessary to adhere to the algorithm of work and safety precautions. So, when working with a liquid nutrient medium, it is necessary to ensure that it does not spill out and does not wet the edges of the cork and test tubes. When the study is carried out with solid material, a special needle is often used to enter the culture. When sowing and reseeding are carried out, they should be carried out near the flame of a gas burner. For the purity of the experiment, the test tube should not remain open for a long time. As for the tool with culture: you should make sure that it does not touch anything. Also, the technique of bacteriological research provides for burning the edges of the test tube before closing it. A finished product should be signed immediately after production to avoid future confusion.
Sowing efficiency
It is believed that this method allows obtaining more accurate and reliable data during bacteriological diagnosis than the previously considered bacterioscopy. In this case, the algorithm of actions is as follows:
- Initially, a pure culture is smeared over the surface of the nutrient medium, which is poured into a Petri dish.
- Initial sowing should be done in conditions that are favorable for the speciesmicroorganisms.
- After a day or two, in the presence of an optimal environment, all suitable colonies move to where they can develop to the maximum. This frees them, thus, from extraneous microflora.
The end result is a culture of homogeneous bacteria that can be identified.
Pure cultures
But how are they made? For this, biological and mechanical methods are used. In the first case, a large role is played by nutrient media, where there are necessary conditions favorable for the development of a particular culture. An approach can also be used when laboratory animals susceptible to a particular type of bacteria become infected. Mechanical methods are based on the use of a sterile instrument, with which the culture is placed in a nutrient medium located in the first, second and third Petri dishes. Then it is necessary to wait until individual colonies grow, and a pure culture will already stand out from them. Bacteria can also be grown in special thermostats, where the temperature is maintained at a certain level (usually about 37 degrees). In this case, the process continues for about a day. But, depending on the type of microorganisms, other terms may be established. Also important is the presence of the required concentration of oxygen. To do this, use various methods of aeration. So far, we have been talking about the situation as a whole and in general, but now let's focus our attention on what the scheme of bacteriological research is.
Practice
A set of methods is often used to detect pathogenic microorganisms in the body of a patient or potential carrier. The materials and methods used depend on the goals of the analysis, as well as on the conditions of the environment in which the work is carried out. In practice, most often bacteria are detected through blood cultures taken from a person or animal. If local lesions are well defined, pathogens can be searched for in problem areas. This is typical for such ailments as dysentery, gonorrhea, diphtheria, and a number of the like. In especially severe cases, this process is divided into separate stages of bacteriological examination (which is typical for typhoid fever). Each of them uses its own methods, which are aimed at finding the cause of infection. Let's take a closer look at the situation with typhoid fever. In the first week of the disease, the most reliable way to diagnose the disease is blood cultures. On the second, a serological study is considered to be such. In the third week, stools are examined. The last method is considered to be checking convalescents.
Microorganism identification
It starts with the process of dyeing it. Then they look at how the bacterium can break down carbohydrates, amino acids, and so on. Additionally, this process can be supplemented by the study of other properties that each individual genus or species of microorganisms possesses. As an example, the possibilities of dissolving erythrocytes of various animals, the effect on blood plasma coagulation and clot dissolution should be given.fibrin and so on. All this is the differential features of individual representatives of the microworld. Also, serological identification can be used for final recognition (but this usually concerns pathogenic bacteria that belong to the intestinal family).
Conclusion
It should be noted that a number of microorganisms cannot be identified by the methods described in the article. In this case, the practice of infecting laboratory animals is widely used. The calculation is made on the fact that characteristic toxigenicity or pathogenicity will appear, which is not observed under artificial conditions. Infection can also be used as a method for the accumulation of pathogenic microbes. And already when the characteristics of the studied culture, found in the process of studying biological, morphological, serological and biochemical properties, are compared, we can say that it is known what kind of microbes we are dealing with. Identification means an indication of the genus, species and type of bacterium. If the microorganism under study deviates in certain properties from its typical characteristic, then this must be indicated. A number of experts believe that in such cases it will be useful to re-identify with duplication of all methods and techniques used. Sometimes research can be taken to the next level, which requires a more serious (and more costly) approach. If negative results were obtained, then this indicates that the preparationmicroorganisms were absent or they were not viable. But for the accuracy of research, if a number of bacillus carriers are suspected (dysentery, diphtheria, typhoid fever), repeated checks are shown in such cases. This is necessary so that specialists have an accurate idea of \u200b\u200bwhat they have to deal with.
