The causative agent of syphilis. Taxonomy
No. 23 The causative agent of syphilis. Taxonomy. Characteristic. Microbiological diagnostics. Treatment.
Treponema palladium; T. entericum
Morphology: typical treponemas with 8-12 whorls, locomotor system - 3 periplasmic flagella at each pole of the cell. Gram stain is not perceived, according to Romanovsky-Giemsa - slightly pink, detected by impregnation with silver.
cultural properties: virulent strain on pet. media does not grow, the accumulation of culture occurs by infecting the rabbit in the testicle. Virulent strains are cultivated on media with brain and kidney tissue.
Biochemical properties: microaerophile
Antigenic structure: complex, has specific protein and lipoid antigens, the latter is identical in composition to cardiolipin extracted from bovine heart (diphosphadylglycerol)
Pathogenicity factors: adhesins are involved in the attachment process, lipoproteins are involved in the development of immunopathological processes.
Resistance: sensitive to drying, sunlight, remains on objects until dry. Under unfavorable conditions, it passes into L-forms and forms cysts.
Pathogenesis: Cause syphilis. From the site of the entrance gate, treponemas enter the regional lymph nodes, where they multiply. Further, T. penetrates into the bloodstream, where it attaches to endotheliocytes, causing endarteritis, leading to vasculitis and tissue necrosis. With the blood, T. spreads throughout the body, seeding organs: the liver, kidneys, bone, cardiovascular, and nervous systems.
Immunity: No protective immunity is developed. In response to pathogen antigens, HRT and autoimmune processes develop. Humoral immunity is produced against the lipoid antigen of T. and is a titer of IgA and IgM.
microscopic examination.
It is carried out with primary syphilis during the appearance of a hard chancre. Material for research: chancre discharge, contents of regional lymph nodes, from which a "crushed" drop preparation is prepared and examined in a dark field. With a positive result, thin twisted threads 6-14 microns long are visible, having 10-12 uniform small curls of the correct shape. Pale treponema is characterized by pendulum-like and forward-flexing movements. With the development of lesions on the oral mucosa with secondary syphilis, as well as with the localization of a hard chancre in the oral cavity, it is necessary to differentiate pale treponema from saprophytic treponemas, which are representatives of the normal microflora. In this case, the detection of typical treponemas in the punctate of regional lymph nodes is of decisive diagnostic importance.
Serodiagnostics. The Wasserman reaction is set simultaneously with 2 antigens: 1) specific, containing the pathogen antigen - treponema destroyed by ultrasound; 2) non-specific - cardiolipin. The investigated serum is diluted in a ratio of 1:5 and RSK is placed according to the generally accepted method. With a positive reaction, a delay in hemolysis is observed, with a negative reaction, hemolysis of erythrocytes occurs; the intensity of the reaction is estimated accordingly from (+ + + +) to (-). The first period of syphilis is seronegative and is characterized by a negative Wasserman reaction. In 50% of patients, the reaction becomes positive no earlier than 2-3 weeks after the appearance of a hard chancre. In the second and third periods of syphilis, the frequency of positive reactions reaches 75-90%. After the course of treatment, the Wasserman reaction becomes negative. Parallel to the Wasserman reaction, a microprecipitation reaction is performed with a nonspecific cardiolipin antigen and the studied inactivated blood serum or plasma. 3 drops of serum are applied to the well on a plexiglass plate (or on ordinary glass) and 1 drop of cardiolipin antigen is added. The mixture is thoroughly mixed and the results are taken into account. A positive reaction with the blood serum of a patient with syphilis is characterized by the formation and loss of flakes of various sizes; with a negative result, uniform light opalescence is observed.
RIF - indirect immunofluorescence reaction - is specific in the diagnosis of syphilis. A suspension of tissue treponemas is used as an antigen. The reaction RIF_200 is used. The patient's serum is inactivated in the same way as for the Wassermann reaction, and diluted in a ratio of 1:200. Drops of antigen are applied to glass slides, dried and fixed for 5 minutes in acetone. Then the patient's serum is applied to the drug, after 30 minutes it is washed and dried. The next step is the treatment of the preparation with fluorescent serum against human globulins. Examine the preparation using a fluorescent microscope, noting the degree of treponema luminescence.
The RIT reaction of treponema immobilization is also specific. A live culture of treponema is obtained by cultivation in a rabbit testicle. The testicle is crushed in a special medium in which treponemas remain mobile. The reaction is set up as follows: a suspension of tissue (mobile) treponemas is combined in a test tube with the test serum and fresh complement is added. Serum of a healthy person is added to one control tube instead of the test serum, and inactivated - inactive complement is added to the other instead of fresh complement. After keeping at 35 °C under anaerobic conditions (anaerostat), a “crushed” drop preparation is prepared from all test tubes and the number of mobile and immobile treponemas is determined in a dark field.
Treatment: Penicillins, tetracyclines, bismuth-containing drugs.
Syphilis is a cyclically occurring sexually transmitted disease in humans caused by spirochete pallidum; Stage I is manifested by hard chancre (fr. chancre- ulcer), II stage - damage to the walls of blood vessels and various rashes, III - gummas in various organs with damage to the nervous system. Gumma (lat. . gummi- gum) - a chronic infiltrate in the form of a node, prone to decay and ulceration. Syphilitic gumma ( syn.: syphilitic granuloma, gummous syphilis, tertiary syphiloma) is a painless hemispherical gum that is a manifestation of tertiary active syphilis. Pathogen - Treponema pallidum- was discovered in 1905 by F. Shaudin and E. Hoffmann.
T. pallidum- a microorganism of a spiral shape, with dimensions of 0.09 - 0.18 x 6 - 20 microns. The number of curls of the spiral is from 8 to 12, the curls are uniform, located at the same distance from each other about 1 μm, the height decreases towards the ends. In an electron microscope, it looks like a snake or an earthworm. At both ends of the treponema there are blepharoplasts with flagella attached to them, the number of which varies from two to several, they form an axial thread twisted around the protoplasmic cylinder of the spirochete. Under unfavorable conditions, it can form cysts. In animals, a capsule-like sheath of mucopolysaccharide nature can occur.
Treponema stains poorly with aniline dyes, which is why the causative agent of syphilis is called pale spirochete. Reduces silver nitrate to metallic silver, which is deposited on the surface of the microbe and makes it visible in the tissues: when stained according to Morozov, treponemas look brown or almost black. When stained according to Romanovsky - Giemsa, they acquire a pale pink color.
Treponemas usually multiply by transverse division, while the divided cells can adjoin each other for some time. The division time is about 30 hours.
Live treponemas are very mobile, they make movements around their own longitudinal axis, as well as flexion, wave-like and translational movements.
To date, there is no such method that would be able to consistently obtain treponema cultures. Treponema pallidum, pathogenic for humans, has never been cultivated on artificial nutrient media, in chicken embryos or in cell cultures. Those varieties of their strains that grow under anaerobic conditions are probably saprophytic spirochetes, close to the causative agent of syphilis. Their physiology remains little studied. Treponemas are chemoorganotrophs, do not have catalase and oxidase, and can ferment carbohydrates. They grow on very rich media containing up to 11 amino acids, vitamins, salts, and serum albumin. The best way to grow pathogenic spirochetes is to infect a rabbit in the testicle (experimental orchitis). It has been suggested that there is T. pallidum life cycle, including, in addition to the spiral shape, the granular stage and the stage of cyst-like spherical bodies. It is the granular forms of these microorganisms that are able to pass through bacterial filters.
Treponema antigens are poorly understood. It has been established that treponema contains protein, polysaccharide and lipid complexes. The antigenic composition of cultural and tissue treponemas is so close that antigens prepared from cultural treponemas can be used for CSC in the diagnosis of syphilis. In the human body, treponemas stimulate the production of antibodies that cause immobilization and death of live mobile treponemas, bind complement in the presence of a suspension T. pallidum or related spirochetes, and are also detected in the indirect RIF.
The causative agent of syphilis does not form exotoxins. Pale treponemas are relatively unstable to external influences. They die quickly when dried and at elevated temperatures (at 55 °C for 15 minutes). In a 0.3 - 0.5% HCl solution, they instantly lose their mobility; they also quickly lose it and die in the presence of arsenic, bismuth, and mercury preparations. In whole blood or in serum at 4 °C, they remain viable for 24 hours, which should be taken into account when transfusing blood.
Epidemiology. Syphilis is a typical sexually transmitted disease. The source of infection is a sick person, usually contagious for 3 to 5 years; patients with late forms of syphilis are not contagious. Infection in the vast majority of cases occurs through various types of sexual and domestic contacts, rarely transplacental from a sick mother to a child (congenital syphilis) or as an occupational infection by contact with medical personnel. Under natural conditions, only a person suffers from syphilis, in the experiment it is possible to infect monkeys, hamsters and rabbits. In monkeys, a hard chancre develops at the injection site of treponems; in rabbits and hamsters, the infection is asymptomatic.
Pathogenesis and clinic. The incubation period for acquired syphilis varies from 2 to 10 weeks, usually 20 to 28 days. The entrance gates of infection are most often the mucous membranes of the genital organs, less often - the oral cavity, as well as damaged skin. At the site of introduction, the pathogen multiplies, a primary syphiloma (hard chancre) is formed - erosion or an ulcer with a compacted base. Further, the pathogen enters the lymphatic system, lymphangitis and regional lymphadenitis develop. This is a typical clinic of primary syphilis, which lasts 1.5 - 2 months. Then these signs disappear. The secondary period of syphilis is associated with a generalization of the process, when many lymph nodes increase, and rashes appear on the skin and mucous membranes; damage to internal organs and the nervous system can be observed. There are secondary fresh and secondary recurrent syphilis. With each subsequent relapse, the intensity of the rash becomes less pronounced, and the periods between relapses increase. The elements of the rash contain a large number of live treponema, during this period the patient is most contagious. The duration of secondary syphilis is up to 4 years or more. Further, the disease enters a long asymptomatic period, after which, after a few years, tertiary syphilis develops. At the same time, gross organic lesions of internal organs, the cardiovascular system, the central nervous system, bones are observed, gummas are formed, accompanied by tissue breakdown and degenerative changes. A characteristic clinical feature of syphilis is the absence of any subjective complaints from the patient (pain, itching, burning, etc.).
Immunity. Against syphilis, neither natural nor artificial immunity arises; there is only infectious immunity, and while it exists, a person is practically not susceptible to a new infection. Infectious immunity develops 10–11 days after the appearance of a hard chancre (chanker immunity), during this period, re-infection is either not observed, or a new chancre that has formed proceeds abortively (superinfection). In the future, with superinfection, the nature of the resulting lesions corresponds to the stage of the disease at the time of re-infection. Superinfection is explained by a temporary weakening or “breakdown” of infectious immunity. From superinfection, it is necessary to distinguish reinfection, i.e., a new, re-infection of a person who previously had syphilis (cured) and, therefore, lost infectious immunity. Cases of even three times the disease with syphilis are described. The incubation period in such patients is shorter, multiple ulcerative chancres with lymphadenitis develop more often, serological reactions become positive earlier. In the secondary period, papules on the skin are often eroded. This is explained by the fact that with syphilis a delayed-type hypersensitivity reaction develops, after treatment, sensitized lymphocytes remain in the body for a long time. Infectious immunity is non-sterile in nature and is due to humoral factors: immunoglobulins of classes G, A and M are found in the patient's serum.
Laboratory diagnostics. For the diagnosis of syphilis, an integrated approach is optimal, involving the simultaneous use of several methods. They are traditionally divided into direct ones, which make it possible to prove the presence of a pathogen in the test material (infection of animals, various types of microscopy and molecular genetic methods for DNA detection). T. pallidum- PCR and DNA probing), and indirect - serological tests to detect antibodies. In turn, serological tests are represented by non-treponemal and treponemal.
The test material for the detection of treponema in direct methods is the discharge of a hard chancre or its punctate, punctate of the lymph node, roseola scraping, cerebrospinal fluid. The pathogen is best detected in native material by dark-field (see Fig. 111.4) or phase-contrast microscopy, which makes it possible to observe different types of movement of a living pathogen. If antibiotic treatment has already been started, the pathogen cannot be detected in the pathological material. If necessary, direct (or indirect) RIF is carried out or the preparation is stained according to Romanovsky-Giemsa. These methods are used only for the early diagnosis of syphilis.
Serological tests can be used at various stages of the disease, except for seronegative primary syphilis. A complex of serological reactions is usually used. TO non-treponemal tests with a visual determination of the results include: the complement fixation reaction (Wassermann reaction \u003d RSKk \u003d RW) with the cardiolipin antigen of the heart muscle of the bull (cross-reacting antigen), microprecipitation reaction (MR, or RMP) - microreaction with plasma and inactivated serum; RPR - rapid plasma reagin test, and other reactions. Experts believe that it is best to use two tests for mass screening: RPR and RPHA or ELISA, since RPR is more sensitive in primary syphilis, RPHA at later stages of the disease, and ELISA at all stages. Microscopically readable non-treponemal tests include the VDRL test and the USR test. Non-treponemal tests are used as screening tests, as they can give false positive results. IN treponemal tests use antigens of treponemal origin. They are used to confirm the results of non-treponemal tests (false positive?) with clinical, epidemiological and anamnestic suspicion of syphilis, for the diagnosis of latent and late forms, for a retrospective diagnosis. Treponemal tests include: RSKt (RSK with treponemal antigen), RIBT (or RIT) - the reaction of pale treponema immobilization, RIF (one of the best reactions), RPHA, ELISA, immunoblotting.
Microbiological diagnosis of syphilis
Practical work
Medicine and Veterinary
The name "pale" treponema received because of the low ability to color. There are other pathogenic treponemas: T. pertenue - the causative agent of yaws, T. carateum - the causative agent of the pint, T. bejel - the causative agent of chronic generalized spirochetosis (bejel). Specified causative agents and called ...
Methodological instructions for students for practical lesson No. 36.
Lesson topic:
Target: Study of methods of microbiological diagnostics, therapy and prevention of syphilis.
Module 2 . Special, clinical and ecological microbiology.
Topic 36: Microbiological diagnosis of syphilis.
Relevance of the topic:
The causative agent of syphilis
Syphilis is an infectious sexually transmitted disease caused by Treponema pallidum, characterized by damage to the skin, internal organs, bones, and nervous system. There are acquired and congenital syphilis.
Taxonomy. The causative agent of syphilis - pale treponema (Treponema pallidum) - was discovered in 1905 by F. Shaudin and E. Hoffman; belongs to the Spirochaetaceae family, Gracilicutes division.
Morphology and tinctorial properties.The name "pale" treponema received because of the low ability to color. There are other pathogenic treponemas: T. pertenue - the causative agent of yaws, T. carateum - the causative agent of the pint, T. bejel - the causative agent of chronic generalized spirochetosis (bejel). These pathogens and the diseases they cause are more common in regions with a hot and humid climate. Pale treponema - a thin spiral-shaped bacterium, 4 to 14 microns long, with uniform small curls (8-14 curls); along with spiral can have other forms - in the form of cysts, granules, L-forms; stained according to Romanovsky-Giemsa in a characteristic faint pink color. Movements from helical to flexion.
Cultivation.Pale treponema is an obligate anaerobe, extremely fastidious to nutrient media. Treponema cultured on nutrient media - cultural spirochete - differs from pathogenic lower virulence, but their antigens are similar, which is used in the serodiagnosis of syphilis.
Antigenic structure.Pale treponema is characterized by antigenic associations with other treponemas, as well as lipoids of animal and human tissues. Several antigens have been identified in the pathogen, one of which, the lipoid antigen, is identical to the lipoid extract of the bovine heart.
resistance. In the environment, pale treponema is weakly resistant; at 55 0 C dies within 15 minutes, sensitive to drying, light, mercury salts, bismuth, arsenic, penicillin. On household items, it remains infectious until it dries; well preserved in cadaver tissue.
animal susceptibility.Experimentally, a pathological process can be induced in the testis and on the skin of rabbits, and in the skin of great apes.
Epidemiology. The source of infection is a sick person. Infection occurs mainly through sexual contact, rarely through household items (glasses, toothbrushes, cigarettes, etc.) contaminated with discharge from the patient; infection through kisses, milk of a nursing mother (household syphilis) is possible, cases of infection during blood transfusion from donors with syphilis are not excluded.
Pathogenesis and clinical picture.The causative agent of syphilis enters the body through the skin or mucous membrane, spreads through organs and tissues, causing their damage. The incubation period lasts an average of 3-4 weeks. After the incubation period, syphilis proceeds cyclically in the form of primary, secondary and tertiary periods. At the site of the introduction of the pathogen (on the genitals, in the oral cavity, etc.), a primary lesion appears - a hard chancre - a sharply demarcated seal with an ulcer on the surface. The secondary period of syphilis lasts 3-4 years, is characterized by a rash, a violation of the general condition of the body. The tertiary period is characterized by damage to the skin, mucous membranes, internal organs, bones, nervous system: formations appear that are prone to decay, ulceration.
Immunity. There is no innate immunity to syphilis. With syphilis, non-sterile immunity develops; After treatment, immunity is not preserved, so repeated diseases are possible.
Dark field microscopy is used to detect pale treponema in the discharge of a hard chancre. By the end of the primary and in the secondary period, Wassermann's sergological reactions, sedimentary reactions of Kahn, cytocholic and other tests that detect antibodies to pale treponema become positive. In mass examinations, a selection reaction, or microreaction on glass, with a drop of blood or serum and a special antigen is used. Research laboratories also use the treponema immobilization reaction and other modern methods.
Scheme of microbiological research in syphilis
Microscopic examination Serodiagnostics
(complex of serological reactions):
Wasserman reaction
Treponema immobilization reaction
Microscopy of the native preparation RIF
In the dark field
ANSWER ANSWER
Treatment. The most effective antimicrobial agents are antibiotics of the penicillin series. Preparations of bismuth, iodine, etc. are also used.
Prevention. There is no specific prophylaxis. Non-specific prevention consists in observing the rules of hygiene, as well as in carrying out a complex of sanitary and hygienic measures of a public nature: accounting for patients with syphilis, hospitalization of all patients with infectious forms, involving all family members of the sick person in the examination, systematic examination of risk groups, education of the population, etc.
Specific goals:
Familiarize yourself with the morphology of the causative agent of syphilis.
Determine the features of the clinical course of syphilis.
Define the concepts of "tissue" and "cultural" treponema.
Interpret the results of microscopic examination.
To study the methods of serological diagnosis of syphilis.
Familiarize yourself with the methods of prevention and specific therapy.
Be able to:
- Collect material for research from patients
- Interpret the results of microscopic examination
- Know how to carry out the Wasserman reaction
Theoretical questions:
1. Pathogen.
- Properties. resistance.
- Pathogenicity for humans and animals. Pathogenic factors, toxins.
- Pathogenesis of the disease in humans, immunity.
- Microbiological diagnostics.
- Specific prevention and treatment
2. Goals of setting the Wasserman reaction.
3. Diagnostic value of the Wassermann reaction and sedimentary reactions.
4. Mechanism of the Wasserman reaction.
5. Features of immunity in syphilis.
Practical tasks that are performed in the classroom:
- Microscopy of demonstration preparations.
- Sketching of demonstration micropreparations in the protocol.
- Analysis of the scheme of laboratory diagnostics.
- Formulation of the protocol.
Literature:
1. Korotyaev A.I., Babichev S.A., Medical microbiology, immunology and virology / Textbook for medical universities, St. Petersburg: “Special literature”, 1998.- 592p.
2. Timakov V.D., Levashev V.S., Borisov L.B. Microbiology / Textbook.-2nd ed., Revised. and additional - M.: Medicine, 1983, - 512s.
3. Pyatkin K.D. Krivoshein Yu.S. Microbiology with virology and immunology. - Kyiv: Vishcha school, 1992. - 431s.
4. Medical microbiology /Edited by V.I. Pokrovsky.- M.: GEOTAR-MED, 2001.- 768s.
5. Guide to practical exercises in microbiology, immunology and virology. / Ed. M.P. Zykova.- M. "Medicine". 1977. 288s.
6. Cherkes F.K., Bogoyavlenskaya L.B., Belskan N.A. Microbiology. / Ed. F.K. Cherkes. M.: Medicine, 1986. 512s.
7. Lecture notes.
Additional literature:
1. Makiyarov K.A. Microbiology, virology and immunology. - Alma-Ata.: "Kazakhstan", 1974. 372p.
2. Titov M.V. Infectious diseases. - K., 1995. 321s.
3. Shuvalova E.P. Infectious diseases.- M.: Medicine, 1990.- 559s.
4. BME, Vol. 1, 2, 7.
5. Pavlovich S.A. Medical microbiology in graphs: Proc. allowance for medical in-tov. Mn.: Vysh. school, 1986. 255p.
Brief guidelines for work in a practical lesson.
At the beginning of the lesson, the level of preparation of students for the lesson is checked.
- Independent work.
- formulation of the Wasserman reaction.
- Accounting for the Wasserman reaction and recording in the protocol.
- Analysis and recording of laboratory diagnostic schemes in the protocol.
The composition of independent work also includes microscopy of demonstration preparations and their sketching in the protocol of the lesson.
At the end of the lesson, a test control and analysis of the final results of each student's independent work is carried out.
Technological map of the practical lesson
|
No. p \ p |
Stages |
Time in min. |
Ways of learning |
Equipment |
Location |
|
Checking and correcting the output level of preparation for the lesson |
20 |
Output Level Test Items |
Tables. Subject tests. |
study room |
|
|
Independent work |
35 |
Graph logical structure |
Collection of demonstration preparations, biological preparations. |
||
|
Self-control and correction of learned material |
15 |
Targeted training programs |
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|
Test control |
15 |
Tests |
|||
|
Analysis of the results of work |
Algorithm of laboratory work:
The study of the scheme of laboratory diagnosis of syphilis.
Microscopy of prepared smears from cultural and tissue treponemas.
Familiarization with the rules for taking material from patients for microscopy of the test material.
Microscopy and analysis of demonstration preparations.
Drawing preparations in the protocol.
Recording schemes of laboratory diagnostics in the protocol.
Formulation of the protocol.
Test control and analysis of the results of independent work of each student.
Targeted learning tasks:
1. A patient with a diagnosis of "primary syphilis" was admitted to the ATC. Which of the following diagnostic methods is used at this stage of the disease?
A . dark field microscopy;
C. RP in gel
D. RA
E . indirect immunofluorescence
2. In a patient of the department of maxillofacial surgery, when staging the Wasserman reaction, it turned out to be negative. Which of the following results determine the phenomenon of negative RSK?
A . by agglutination of erythrocytes;
B . by the presence of erythrocyte sediment;
C . by changing the color of the liquid;
D . by film formation
E . by the presence of hemolysis in test tubes.
3. Examination of a patient with CVA revealed papular-roseolous rashes on the trunk and extremities and enlarged lymph nodes. Preliminary diagnosis of syphilis. What method of laboratory diagnostics can confirm this diagnosis?
A. allergic;
b. biological;
C . bacteriological;
D . bacterioscopic;
E. ELISA
4. During the reception, the dentist found a hard chancre in the patient's oral cavity. Which of the following methods of laboratory diagnostics can be used to make a diagnosis?
A . treponema immobilization reaction
B . Wassermann reaction
C. Kahn reaction
D. RA
E . bacterioscopic
5. A woman came to the antenatal clinic at the 8th week of pregnancy. During the examination, blood was taken from her to check for the presence of specific antibodies to treponema. Which of the following serological tests can be used to detect antibodies to treponema?
A. Wright's reaction
B . Wassermann reaction
C. Vidal reaction
D . Bordet-Gangu reaction
E. RTGA.
6. To confirm the diagnosis of syphilis, the laboratory assistant performed a serological test, in which he used the patient's blood serum, cardiolipid antigen, complement and indicator system. What is the name of the given reaction?
A . treponema immobilization reaction;
B . Wasserman reaction;
C. Kahn reaction
D. RP
E . immunofluorescence reaction.
7. When conducting a serological test for the detection of antibodies to the causative agent of syphilis in the patient's blood serum, treponemas were incubated with the patient's serum under anaerobic conditions, after which the bacteria lost their mobility. What was the reaction and what does it mean?
A . Wasserman reaction, the patient has syphilis;
B .Wasserman's reaction, the patient has an incubation period;
C . treponema immobilization reaction, the patient has syphilis;
D . indirect immunofluorescence reaction, the patient has syphilis;
E . treponema immobilization reaction, the patient once had syphilis.
8. For the serological diagnosis of syphilis using the Wasserman reaction, the laboratory assistant prepared the following reagents: cardiolipid antigen, isotonic sodium chloride solution, hemolytic system. What other component is needed to stage this reaction?
A . live treponemas;
B . sheep erythrocytes;
C. complement;
D . antiglobulin serum;
E . diagnostic precipitating serum.
9. In a micropreparation prepared from a punctate of the patient's lymph nodes, stained according to Romanovsky-Giemsa, the doctor revealed thin microorganisms with 12-14 uniform curls of pale pink color. About the causative agent of what infectious disease can we talk about in this case?
A . relapsing fever;
b. leptospirosis;
C. leishmaniasis
D. syphilis
E. trypanosomiasis.
10. A scraping from the oral mucosa was taken from a patient with suspected primary syphilis. Microscopy of a smear stained according to the Romanovsky-Giemsa method revealed convoluted purple bacteria. Which of the following conclusions is correct?
A . the patient has been diagnosed T. pallidum;
B . The patient has an atypical form T. pallidum;
C . the patient has non-pathogenic treponemas;
D . the wrong staining method was chosen;
E. -
11. The clinician suspected primary syphilis in a patient. What research material should be taken to confirm the diagnosis?
A . tissue fluid from hard chancre and punctate of lymph nodes;
B . scraping from skin rashes;
C. liquor;
D. mucus from the nose
E. saliva.
12. Blood was taken from a patient with suspected secondary syphilis. What diagnostic method should be used to confirm the diagnosis?
A . Vidal reaction;
B . allergic test;
D . Bordet-Gangu reaction
E . bacteriological method
C . indirect immunofluorescence reaction.
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T. pallidum subspecies pallidum - a spiral bacterium 6-14x0.2-0.3 microns in size; in cultures can be large. The curls of the spiral are the same but in height, there can be up to 14 of them. They are able to form an L-form.
Basic how syphilis spreads- transverse division. The causative agent of syphilis it is not stable in the external environment and dies when it dries out, but it persists in the cold for up to 50 days. Heating at a temperature of 40 ° C for an hour leads to the loss of pathogenic properties; at 48 °C bacteria die within 10 min.
The causative agent of syphilis poorly stained with aniline dyes (hence the name "pale spirochete"). syphilis bacteria reduce silver nitrate to metallic silver, which gives the fabrics a black or dark brown color.
In domestic practice, the method of silvering according to Morozov is widespread. According to Romanovsky-Giemsa, it turns pink, and non-pathogenic treponema- in purple or blue. Burri negative staining is also used.
Cultural properties of syphilis. Culture of the causative agent of syphilis
Pale spirochete demanding on cultivation conditions, grows poorly on artificial media; methods for stable production of cultures are not yet available.
In our country, the largest number strains of syphilis identified Kazan microbiologists V.M. Aristovsky and P.P. Geltzer.
These "Kazan" strains of syphilis along with the Reiter strain, they are used for the manufacture of Ag for serodiagnosis. With long-term cultivation syphilis bacteria adapt to simpler environments (for example, Kitta-Tarozzi) and lose their pathogenic properties.
Syphilis colonies small, appear on the 3-5th day of cultivation.
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