Treponema pallidum: what is it? Course and complications of syphilis
There are so many different microorganisms that for centuries scientists have not been able to fully study them. For example, there is no consensus among researchers about the occurrence or origin of syphilis. It is believed that this is one of the most ancient diseases, which appeared with the appearance of man.
However, officially the causative agent of syphilis was discovered in 1905 by German microbiologists E. Hoffmann and F. Schaudin. It was they who first discovered a number of biochemical, morphological and cultural properties of pale treponema and its features.
In this article we will try to understand in detail what it is - treponema pallidum. What is its structure, structure, physiological properties, as well as the infectious agent that causes syphilis.
But first, let's define what it means - treponema pallidum. It is the causative agent of syphilis - pale treponema, and it refers to the order of Spirochaetales.
Syphilis is a venereal chronic disease that is sexually transmitted.The incubation period of the body is about three weeks. After that, in the place where the pathogen was introduced, the primary affect appears in the form of a chancre or a painless ulcer. If untreated, secondary and tertiary syphilis develops.
Antibodies to treponema pallidum - what is it?
In response to the development of infection, the human immune system produces antisyphilitic antibodies, therefore, serological methods are most often used to diagnose the disease. First, the immune system produces antibodies of the lgM class, then, as the disease progresses, the synthesis of IgG antibodies predominates. Treponema pallidum at the stage of the appearance of these antibodies is characterized by an acute form. They can persist in a patient for life. It turns out that antibodies to treponema pallidum are also diagnostic tools.
Treponema consists of cells with a length of 6-15 microns and a width of 0.1-02 microns. It is a cytoplasm surrounded by a cytoplasmic membrane. In appearance, the cell of this organism resembles a thin curled thread.
Usually the number of curls varies from 8 to 14. Moreover, these curls remain even when moving between other cells.
The photo below shows what kind of microorganism this species has.
Between the cytoplasm and the membrane are fibrils. One part of the fibrils is always free, although the other is fixed and fixed. It is the fibrils that represent the locomotor apparatus of treponema, which allows it to move in a liquid medium. Due to this, the microorganism can move, bend and rotate around its axis.
Treponema pallidum is a gram-negative microorganism, but it is not stained due to the presence of a hydrophobic particle in the composition that is immune to aniline dyes.
According to Romanovsky-Giemsa, the treponema acquires a faint pink color, and this feature to some extent played a role for the name of the pathogen. By itself, the microorganism is quite demanding on the environment. Its comfortable habitat is 30-37 degrees, and it is rather quickly inactivated by mild cold, warmth, and disinfectants.
It is impossible to fully understand what it is - treponema pallidum, without determining its biochemical and cultural properties. In essence, treponema is considered an obligate parasite, therefore it will not survive in artificial nutrient media. Over the past 75 years, it has not been possible to cultivate it in vitro (in vitro).During cultivation, this microorganism loses pathogenicity, however, some antigenic properties are retained. However, treponema is cultivated in the testicles of rabbits, where it multiplies and causes orchitis.
Reproduction of treponema occurs in transverse binary division, the comfortable temperature for this is 37 degrees. Note that in the external environment, the resistance of the organism is very weak:
- Treponema lives outside the human body for a couple of minutes, after which it dries out completely. At a temperature of about 40 degrees, it dies within two hours, and at a temperature of 50 degrees, the treponemes last only 15 minutes.
- Under unfavorable conditions for the body, cysts and L-forms are formed, which later may also acquire a spiral shape.
Note that treponema is a chemoorganic heterotrophic type of metabolism. This means that for life it needs organic substances that serve as sources of energy. It is because of the inability of existence outside the human environment that its biochemical properties are studied very poorly.
The antigenic structure of this organism is poorly understood.It is represented by a thermolabile protein antigen, as well as a polysaccharide antigen. In simple terms, the antigens of treponema pallidum are normal proteins and polysaccharides of the outer membrane of the cell.
The toxic and antigenic function is performed by cell wall lopopolysaccharide. For treponema pallidum, it is an endotoxin.
Pathogenicity factors are also poorly understood. After treponema pallidum enters the macroorganism, it releases lipoproteins and specific proteins - lipopolysaccharides. They exhibit toxic properties after death. Lipoproteins are involved in the activation of the immune system, and proteins are quite similar in some properties to bacterial hemolysins.
The ability of this microorganism to release lipid antigens and endotoxins refers to pathogenicity factors. These elements possess the properties of autoantigens.
Now we are more or less clear what it is - Treponema Pallidum. In the laboratory, syphilis can be diagnosed in two ways:
- Identification of the causative agent of the disease with the help of biological preparations.
- Serological reactions.
The latter method of diagnosis can be used for diagnosis and to assess the effectiveness of treatment. The peculiarity of serology is that positive results in the early stages of the disease may be completely absent, although the patient will have symptoms. This is easily explained: the incubation period for syphilis is 3-5 weeks. However, for people who abuse alcohol, have tuberculosis or HIV infection, the incubation period can last for about two weeks.
When taking antibacterial drugs, the incubation period may increase to 6 months. During this time, the concentration of antibodies is sufficiently small and does not reach the diagnostic titer. But a person can still experience the clinical symptoms of syphilis. This disease is called seronegative syphilis.
Seropositive syphilis is characterized by pronounced symptoms and clinical presentation. Antibodies of treponema pallidum are immediately detected in the blood. A positive result involves the immediate treatment of the disease. Otherwise, seropositive syphilis flows into the secondary, and it can last for years.
The first clinical signs of the disease (except for the appearance of solid chancre) are total treponema pallidum antibodies, that is, IgM and IgG. In addition, an anti-cardiolipin test is performed - RPR. These tests are complementary and, when used together, will help to accurately diagnose or eliminate syphilis disease.
Treatment of the disease
As already mentioned, if the test for antibodies is positive, then resort to the treatment of the disease. It should be aimed at the destruction of the pathogen. Moreover, even preventive treatment is shown for people who do not have a clinical picture, but who have had sexual contact with a person suffering from an early form of syphilis.
Pregnant women with positive and serological tests also receive prophylactic treatment. In the Russian Federation there are treatment regimens for this disease that are systematically updated. Last time they were revised in 1999.
Primary syphilis is treated by prescribing "Benzatin benzylpenicillin" in the amount of 2.4 million IU intramuscularly (2 injections once a week). It is also possible to assign bitsillina-5 to 1.5 million units intramuscularly (2 times a week, 5 injections).
Ampicillin, Ceftriaxone, Doxycycline and other drugs are prescribed as an alternative treatment. In any case, the doctor prescribes the treatment based on the results of the tests.
After a full cycle of treatment, patients should also undergo serological tests for the next two years. If the AT titers (non-treponemal tests) are reduced by a factor of 4 during the year after treatment, then this is considered a good result, allowing one to conclude that the treatment was effective.
Also, all sexual partners of the patient should be treated, regardless of the results of the serological test. As already described above, the serological test can be negative during the incubation period, even despite the presence of treponema pallidum in the human body. What it is, you already know.
Prevention and prognosis
The best prevention of the disease is to avoid casual sex and the use of protective equipment (condoms or chemicals) during sexual intercourse. It is also appropriate to contact round-the-clock STI prevention centers.
When syphilis is detected at the primary or secondary stage, the prognosis is favorable.However, the late stages of the disease will lead to serious consequences: diseases of the cardiovascular system, blindness, mental disorder and disease of the nervous system. Deaths were also recorded.
Now you know what it is - treponema pallidum, and how dangerous syphilis is.
Despite the possible sad consequences, it is almost impossible not to notice the appearance of a pathogen in the body. Any sensible person will turn to a doctor at an early stage of the disease, so you should not worry about the serious consequences. They can occur only at a late stage, if a person does not pay attention to the development of the disease at all.