Mycobacterium tuberculosis in medicine is also known as a stick of Koch. These are pathogenic microorganisms. The bacterium is large in size and has an elongated shape, it has a dense outer shell. In translation from Greek, "myco" means "mushroom", which indicates the similarity of Koch's rod to the mycelium. These microorganisms are very tenacious.
Types of Mycobacterium tuberculosis
All microorganisms of this group can be differentiated into dangerous for humans and conditionally pathogenic. In addition, the bacterium, which is the causative agent of tuberculosis, can be classified according to other criteria. Differentiation is carried out according to the following features:
- growth rate;
- optimal temperature of development;
- the ability of the bacillus to pigment.
All mycobacteria tuberculosis are united in one large group, called M. tuberculosis. Its representatives are:
- M. africanum;
- M. microti;
- M. canettii;
- M. bovis BCG;
- M. sargaye;
- M. pinnipedii and so on.
The remaining bacteria are considered to be a non-tuberculous group. This includes such microorganisms:
- M. intracellulare;
- M. terrae;
- M. scrofulaceum;
- M. chelonae;
- M. fortuitum;
- M. leprae and so on.
Mycobacteria provoke the development of tuberculosis. Is it dangerous. The following groups of mycobacteria of tuberculosis stand out:
- Photochromogenic - representatives of this species in the dark are colorless, but when they get to light they get a bright orange color. Favorable temperature of bacillus development is 32 ° С.
- Skotochromogenic - these microorganisms are formed in the dark, because their very name scotos from the Greek language translates to "darkness". The growth rate varies from 30 to 60 days. When such a bacillus enters a child's or exhausted adult organism, the lymphatic system is affected.
- Neofrochromogenic - representatives of this group are almost colorless, but when they get to light they acquire a pale yellow color. The duration of development is 2-4 weeks.
- Fast - growing - representatives of this group can be colorless and pigmented. Their development is going on at a rapid pace. From the moment of formation to the phase of the finally formed microorganism passes from 7 to 10 days.
Analysis for Mycobacterium tuberculosis
Various diagnostic methods can be used to detect this ailment. Appointed hardware procedures and apply laboratory tests. The first include such methods of diagnosis:
- Fluorography - allows you to get results in minutes;
- X-rays - pictures are performed in a straight and a side projection;
- Computed tomography is the most objective way (it gives the most accurate result).
Laboratory diagnostic methods include:
- sputum analysis on mycobacterium tuberculosis;
- chain polymerase reaction method;
- general analysis of blood and urine;
- smear microscopy;
- an enzyme-linked immunosorbent assay that allows detection of antibodies to mycobacteria of tuberculosis;
- tissue biopsy.
Blood test for mycobacterium tuberculosis
This test involves the identification of immune and enzymatic reactions. During the first, antigens are involved - molecules that carry information about a particular cell. If the immune system does not recognize the secret "code", it signals an "alarm". The antibody binds to the "foreign" antigen and destroys its connection with the cell. Enzymatic reaction occurs when one substance is transformed into another.
Thanks to such complex biochemical processes that take place in the cells of the body, antibodies to mycobacteria of tuberculosis are determined. This analysis is performed on an empty stomach. In addition, a few days before its implementation, the patient should abandon fried foods and fatty foods. The biological fluid is collected by a vacuum system.
In a healthy person, antibodies that belong to groups G and M will not be present in the blood. The detection of these substances indicates the presence of infection in the lungs. However, single detection of these antibodies does not provide an opportunity to deliver an unmistakable diagnosis. To confirm the patient, smear microscopy and fluorography or X-rays can be prescribed.
Sputum examination for mycobacterium tuberculosis
To perform this analysis, a sterile container is used. Immediately before sputum collection is performed on the mycobacterium tuberculosis, the patient should brush his teeth. If this is not done, the results will be distorted by the harmful microorganisms in the oral cavity. Sputum on mycobacterium tuberculosis is better in the morning - after a night's sleep. She spits into a sterile container, which should immediately be closed.
Keep the secret in a dark and cool place. The optimal time from the time of sputum collection to the study is 2 hours. It is carried out by the following methods:
- bacterioscopic;
- bacteriological.
The first method involves the use of a microscope. In the second method, the study is performed as follows:
- Sputum is diluted with a special "reagent".
- The tube is sent to the unit, which creates special conditions for the growth of bacteria.
- The newly formed carbon dioxide is combined with the dye.
- The level of fluorescence is judged on the type of microorganisms in the test sample.
Properties of Mycobacterium tuberculosis
The characteristics of these harmful microorganisms are determined by their chemical composition. Koch's stick is 80% water and 3% ash. The dry residue contains up to 40% of proteins and the same amount of polysaccharides. Atypical mycobacterium tuberculosis (as well as other microorganisms of this group) are highly toxic. It is inherent in both the living and the killed stick of Koch.
Mycobacterium tuberculosis - stability in the external environment
The shelf of Koch is distinguished by its "survivability" from other bacilli. Mycobacterium tuberculosis is resistant to the following environment:
- acid;
- alcoholic;
- alkaline.
In the water, Koch's stick retains its harmful effects for up to 150 days. In dairy products, these bacilli live up to 10 months. Knowing at what temperature the mycobacterium of tuberculosis dies, you can prevent its reproduction. Direct sunlight neutralizes Koch's wand in 4-5 hours. In addition, microorganisms perish for half an hour at a temperature of 85 ° C or more.
Drug resistance of mycobacterium tuberculosis
To identify drugs that are contraindicated in the treatment, an antibiogram is used. There are such reasons for the resistance of Koch's rod to drugs:
- Biological - insufficient dosage of the drug.
- Through the patient's fault - the medication is taken irregularly, the dosage is changed on its own, and so on.
- Consequences of the disease - the tuberculosis causing agent of the disease changes the pH. This interferes with the action of the drug.
Modern disinfectants, acting on the mycobacterium tuberculosis
When choosing the means for sanitary prevention, it is necessary to take into account the high stability of the Koch sticks. The causative agent of tuberculosis dies under the influence of such disinfectants:
- 5% chloramine;
- 0.5% bleach;
- soda ash.
Ways of infection with mycobacteria tuberculosis
Danger to others are patients who suffer from an open form of ailment . The most frequent route of infection with mycobacterium tuberculosis is as follows:
- contact;
- air-drip;
- intrauterine;
- alimentary.