The causative agent of syphilis. Taxonomy
No. 23 The causative agent of syphilis. Taxonomy. Characteristic. Microbiological diagnostics. Treatment.
Treponema palladium; T. entericum
Morphology: typical treponemes with 8-12 whorls, motor apparatus - 3 periplasmic flagella at each cell pole. The Gram stain is not perceived; the Romanovsky-Giemsa stain is faintly pink, revealed by silver impregnation.
Cultural properties: virulent strain on pit. does not grow in environments, the accumulation of the culture occurs through infection of the rabbit in the testicle. Virulent strains are cultured on media containing 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 transforms into L-forms and forms cysts.
Pathogenesis: Causes syphilis. From the entrance gate, treponema enters the regional lymph nodes, where they multiply. Next, T. penetrates the bloodstream, where it attaches to endothelial cells, causing endarteritis, leading to vasculitis and tissue necrosis. With the blood, T. spreads throughout the body, seeding the organs: liver, kidneys, bone, cardiovascular, and nervous systems.
Immunity: protective immunity is not developed. In response to pathogen antigens, HRT and autoimmune processes develop. Humoral immunity is developed in response to T. lipoid antigen and is a titer of IgA and IgM.
Microscopic examination.
Carry out for primary syphilis during the appearance of chancre. Material for research: chancre discharge, the contents of regional lymph nodes, from which a “crushed” drop is prepared and examined in a dark field. If the result is positive, thin crimped threads 6-14 microns long are visible, having 10-12 uniform small curls of regular shape. Treponema pallidum is characterized by pendulum-like and translational-flexion movements. With the development of lesions on the oral mucosa during secondary syphilis, as well as with the localization of chancroid in the oral cavity, it is necessary to differentiate Treponema pallidum from saprophytic Treponema, which are representatives of normal microflora. In this case, the detection of typical treponemas in the punctate of regional lymph nodes is of decisive diagnostic importance.
Serodiagnosis. The Wasserman reaction is performed simultaneously with 2 antigens: 1) specific, containing the antigen of the pathogen - treponemes destroyed by ultrasound; 2) nonspecific - cardiolipin. The test serum is diluted in a ratio of 1:5 and RSC is placed according to the generally accepted method. With a positive reaction, a delay in hemolysis is observed, with a negative reaction, hemolysis of red blood cells occurs; the intensity of the reaction is assessed 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 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. In parallel with the Wasserman reaction, a microprecipitation reaction is performed with a nonspecific cardiolipin antigen and the test inactivated blood serum or plasma. 3 drops of serum are applied to a well on a plexiglass plate (or regular 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 different sizes; with a negative result, uniform light opalescence is observed.
RIF - indirect immunofluorescence reaction - is specific for the diagnosis of syphilis. A suspension of tissue treponemes 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 in acetone for 5 minutes. Then the patient’s serum is applied to the preparation, after 30 minutes it is washed and dried. The next step is to treat the drug with fluorescent serum against human globulins. The preparation is studied using a fluorescent microscope, noting the degree of luminescence of the treponemes.
The RIT reaction of immobilization of treponemes is also specific. A live culture of Treponema is obtained by cultivating it in a rabbit testicle. The testicle is crushed in a special medium in which the treponemes remain motile. The reaction is set up as follows: a suspension of tissue (motile) treponemes is combined in a test tube with the test serum and fresh complement is added. In one control tube, instead of the test serum, the serum of a healthy person is added, in the other, instead of fresh complement, inactivated - inactive - is added. After keeping at 35 °C under anaerobic conditions (anaerostat), a “crushed” drop is prepared from all test tubes and the number of mobile and immobile treponemes is determined in a dark field.
Treatment: Penicillins, tetracyclines, bismuth-containing drugs.
Syphilis is a cyclical human venereal disease caused by a pallidum spirochete; 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. Schaudin and E. Hoffmann.
T. pallidum– a spiral-shaped microorganism, dimensions 0.09 – 0.18 x 6 – 20 microns. The number of spiral turns is from 8 to 12, the turns are uniform, located at the same distance from each other, about 1 micron, the height decreases towards the ends. In an electron microscope it looks like a snake or 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 the body of animals, a capsule-like case of a mucopolysaccharide nature may appear.
Treponema does not stain well with aniline dyes, which is why the causative agent of syphilis is called the pale spirochete. Reduces silver nitrate into metallic silver, which is deposited on the surface of the microbe and makes it visible in the tissues: when stained according to Morozov, treponemas appear brown or almost black. When stained according to Romanovsky-Giemsa, they acquire a pale pink color.
Treponemas usually reproduce by transverse division, and the divided cells may adhere to each other for some time. Division time is about 30 hours.
Living treponemes are very mobile, making movements around their own longitudinal axis, as well as flexion, wave-like and translational movements.
To date, there is no method by which it would be possible to stably obtain treponeme cultures. Treponema pallidum, pathogenic to humans, has never been cultivated in artificial nutrient media, in chicken embryos or 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 studied. It has been established that treponemes contain protein, polysaccharide and lipid complexes. The antigenic composition of cultural and tissue treponemes is so close that antigens prepared from cultural treponemes can be used for RSC in the diagnosis of syphilis. In the human body, treponemes stimulate the production of antibodies, which cause immobilization and death of living motile treponemes, fix complement in the presence of a suspension T. pallidum or related spirochetes, and are also detected in indirect RIF.
The causative agent of syphilis does not produce exotoxins. Treponema pallidum is relatively unresistant 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. In whole blood or serum at 4 °C they remain viable for 24 hours, which should be taken into account when blood transfusions.
Epidemiology. Syphilis is a typical venereal 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 household contacts, rarely through the transplacental route from a sick mother to a child (congenital syphilis) or as an occupational infection through contact among medical personnel. Under natural conditions, only humans suffer from syphilis; in experiments, monkeys, hamsters and rabbits can be infected. In monkeys, chancre develops at the site of treponema injection; 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 – 28 days. The entry points for 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 penetration, the pathogen multiplies, and primary syphiloma (hard chancre) is formed - erosion or ulcer with a compacted base. Next, the pathogen enters the lymphatic system, and lymphangitis and regional lymphadenitis develop. This is a typical clinical picture of primary syphilis, which lasts 1.5 - 2 months. Then these signs disappear. The secondary period of syphilis is associated with the generalization of the process, when many lymph nodes enlarge, and rashes appear on the skin and mucous membranes; Damage to internal organs and the nervous system may occur. 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 living treponemas; during this period the patient is most contagious. The duration of secondary syphilis is up to 4 years or more. The disease then enters a long asymptomatic period, after which, after a few years, tertiary syphilis develops. In this case, gross organic damage to the internal organs, cardiovascular system, central nervous system, bones is observed, gummas are formed, accompanied by tissue decay and degenerative changes. A characteristic clinical feature of syphilis is the absence of any subjective complaints from the patient (pain, itching, burning, etc.).
Immunity. There is no natural or artificial immunity against syphilis; There is only infectious immunity, and as long as 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 (chancroid immunity); during this period, re-infection is either not observed, or the newly formed chancre is abortive (superinfection). Subsequently, during 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. It is necessary to distinguish reinfection from superinfection, i.e. a new, repeated infection of a person who previously had syphilis (cured) and, therefore, has lost infectious immunity. Cases of even three cases of syphilis have been described. The incubation period in such patients is shorter, multiple ulcerative chancre with lymphadenitis develops more often, and serological reactions become positive earlier. In the secondary period, papules on the skin often erode. 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 caused by humoral factors: immunoglobulins of classes G, A and M are found in the patient’s serum.
Laboratory diagnostics. To diagnose 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 material under study (infection of animals, various types of microscopy and molecular genetic methods of 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 tests.
The material to be tested for the detection of treponemas in direct methods is chancre discharge or its punctate, lymph node punctate, roseola scraping, and cerebrospinal fluid. The pathogen is best detected in native material by dark-field (see Fig. 111.4) or phase-contrast microscopy, which allows one to observe different types of movement of the living pathogen. If treatment with antibiotics has already begun, the pathogen cannot be detected in the pathological material. If necessary, direct (or indirect) RIF is performed 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. Usually a complex of serological reactions is used. TO non-treponemal tests with visual determination of results include: complement fixation reaction (Wassermann reaction = RSKk = RW) with cardiolipin antigen of bovine heart muscle (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 for mass examination it is best to use two tests: RPR and RPGA or ELISA, since RPR is more sensitive in primary syphilis, RPGA - at later stages of the disease, and ELISA - at all stages. Non-treponemal tests with microscopic reading of the results 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?) for 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) - immobilization reaction of Treponema pallidum, RIF (one of the best reactions), RPHA, ELISA, immunoblotting.
Microbiological diagnosis of syphilis
Practical work
Medicine and veterinary medicine
The name “pale” treponema was given due to its low coloring ability. There are other pathogenic treponemes: T. pertenue - the causative agent of yaws, T. carateum - the causative agent of pint, T. bejel - the causative agent of chronic generalized spirochetosis (bejel). The specified pathogens and those caused...
Guidelines for students for practical lesson No. 36.
Lesson topic:
Target: Study of methods of microbiological diagnosis, therapy and prevention of syphilis.
Module 2 . Special, clinical and environmental microbiology.
Topic 36: Microbiological diagnosis of syphilis.
Relevance of the topic:
The causative agent of syphilis
Syphilis is an infectious venereal 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 - treponema pallidum (Treponema pallidum) - was discovered in 1905 by F. Schaudinn and E. Hoffman; belongs to the family Spirochaetaceae, division Gracilicutes.
Morphology and tinctorial properties.The name “pale” treponema was given due to its low coloring ability. There are other pathogenic treponemes: T. pertenue - the causative agent of yaws, T. carateum - the causative agent of pint, T. bejel - the causative agent of chronic generalized spirochetosis (bejel). These pathogens and the diseases they cause are more common in regions with hot and humid climates. Treponema pallidum is a thin spiral-shaped bacterium, 4 to 14 microns long, with uniform small curls (8-14 curls); along with the spiral shape it can have other forms - in the form of cysts, granules, L-forms; stained according to Romanovsky-Giemsa in a characteristic faint pink color. Movements range from helical to flexion.
Cultivation.Treponema pallidum is an obligate anaerobe, extremely demanding of nutrient media. Treponema cultivated on nutrient media - a cultural spirochete - differs from the pathogenic one in being less virulent, but their antigens are similar, which is used in the serodiagnosis of syphilis.
Antigenic structure.Treponema pallidum is characterized by antigenic connections 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 bovine heart.
Resistance. Treponema pallidum is weakly resistant in the environment; at 55 0 C dies within 15 minutes, is sensitive to drying, light, mercury salts, bismuth, arsenic, penicillin. On household items it remains infectious until it dries; well preserved in cadaveric tissue.
Animal susceptibility.Experimentally, the pathological process can be induced in the testicle and 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 from a nursing mother (domestic syphilis) is possible; cases of infection through blood transfusions from donors with syphilis cannot be ruled out.
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 on average 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 for syphilis
Microscopic examination Serodiagnosis
(set of serological reactions):
Wasserman reaction
Treponema immobilization reaction
Microscopy of the native preparation RIF
In a dark field
REPLY REPLY
Treatment. The most effective antimicrobial agents are penicillin antibiotics. Preparations of bismuth, iodine, etc. are also used.
Prevention. There is no specific prevention. Nonspecific prevention consists in observing the rules of hygiene, as well as in carrying out a set of sanitary and hygienic measures of a public nature: registration of patients with syphilis, hospitalization of all patients with infectious forms, involvement in the examination of all family members of the sick person, systematic examination of risk groups, education of the population, etc.
Specific goals:
Get acquainted 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” treponemes.
Interpret the results of microscopic examination.
Study methods of serological diagnosis of syphilis.
Familiarize yourself with methods of prevention and specific therapy.
Be able to:
- Collect material for research from patients
- Interpret the results of microscopic examination
- Be able to carry out the Wasserman reaction
Theoretical questions:
1. Pathogen.
- Properties. Resistance.
- Pathogenicity for humans and animals. Pathogenicity factors, toxins.
- Pathogenesis of the disease in humans, immunity.
- Microbiological diagnostics.
- Specific prevention and treatment
2. The goals of staging the Wasserman reaction.
3. Diagnostic value of the Wasserman reaction and sedimentary reactions.
4. The mechanism of the Wasserman reaction.
5. Features of immunity in syphilis.
Practical tasks performed in class:
- Microscopy of demonstration preparations.
- Sketching demonstration microslides into the protocol.
- Analysis of the laboratory diagnostic scheme.
- Drawing up 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, - 512 p.
3. Pyatkin K.D. Krivoshein Yu.S. Microbiology with virology and immunology. - Kyiv: Vishcha School, 1992. - 431 p.
4. Medical microbiology /Edited by V.I. Pokrovsky.- M.: GEOTAR-MED, 2001.- 768 p.
5. Guide to practical classes in microbiology, immunology and virology. /Ed. M.P. Zykova.- M. “Medicine”. 1977. 288 p.
6. Cherkes F.K., Bogoyavlenskaya L.B., Belskan N.A. Microbiology. /Ed. F.K. Circassian. M.: Medicine, 1986. 512 p.
7. Lecture notes.
Additional literature:
1. Makiyarov K.A. Microbiology, virology and immunology. - Alma-Ata.: “Kazakhstan”, 1974. 372 p.
2. Titov M.V. Infectious illnesses. - K., 1995. 321 p.
3. Shuvalova E.P. Infectious diseases. - M.: Medicine, 1990. - 559 p.
4. BME, T. 1, 2, 7.
5. Pavlovich S.A. Medical microbiology in graphs: Textbook. allowance for medical in-tov. Mn.: Higher. school, 1986. 255 p.
Brief guidelines for working in a practical lesson.
At the beginning of the lesson, the students' level of preparation for the lesson is checked.
- Independent work.
- staging of the Wasserman reaction.
- Accounting for Wasserman's 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 for conducting a practical lesson
|
No. |
Stages |
Time in min. |
Ways of learning |
Equipment |
Location |
|
Checking and correcting the output level of preparation for a lesson |
20 |
Output Level Tests |
Tables. Tests on the topic. |
Study room |
|
|
Independent work |
35 |
Graph logical structure |
Collection of demonstration drugs, biological products. |
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Self-monitoring and correction of learned material |
15 |
Targeted training programs |
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|
Test control |
15 |
Tests |
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|
Analysis of work results |
Laboratory work algorithm:
Study of the laboratory diagnostic scheme for syphilis.
Microscopy of prepared smears from cultured and tissue treponemes.
Familiarization with the rules for taking material from patients for microscopy of the test material.
Microscopy and analysis of demonstration preparations.
Sketching drugs into the protocol.
Recording laboratory diagnostic schemes in the protocol.
Drawing up the protocol.
Test control and analysis of the results of each student’s independent work.
Target training tasks:
1. A patient was admitted to the hospital with a diagnosis of primary syphilis. 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 from the department of maxillofacial surgery, when the Wasserman reaction was performed, it turned out to be negative. Which of the following results is used to determine the phenomenon of negative RSC?
A . by erythrocyte agglutination;
B . by the presence of red blood cell sediment;
C . by changing the color of the liquid;
D . by film formation
E . by the presence of hemolysis in test tubes.
3. When examining a patient with KVD, papular-roseolous rashes on the torso and limbs and enlarged lymph nodes were revealed. Preliminary diagnosis of syphilis. What laboratory diagnostic method can confirm this diagnosis?
A. allergic;
B. biological;
C . bacteriological;
D . bacterioscopic;
E. ELISA
4. During the appointment, the dentist discovered a hard chancre in the patient’s mouth. Which of the following laboratory diagnostic methods can be used to make a diagnosis?
A . Treponema immobilization reaction
B . Wasserman reaction
C. Kahn reaction
D. RA
E . bacterioscopic
5. A woman came to the antenatal clinic at 8 weeks of pregnancy. During the examination, her blood was taken to check for the presence of specific antibodies to treponemes. Which of the following serological tests can be used to detect antibodies to treponema?
A. Wright's reaction
B . Wasserman reaction
C. Vidal reaction
D . Bordet-Gengou reaction
E. RTGA.
6. To confirm the diagnosis of syphilis, the laboratory technician carried out a serological reaction, in which he used the patient’s blood serum, cardiolipid antigen, complement and an 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 reaction to detect antibodies to the causative agent of syphilis in the patient’s blood serum, treponemes were incubated with the patient’s serum under anaerobic conditions, after which the bacteria lost their mobility. What reaction was given and what does it mean?
A . Wasserman reaction, the patient has syphilis;
B .Wassermann reaction, the patient is in 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 suffered from syphilis.
8. For the serological diagnosis of syphilis using the Wasserman reaction, the laboratory doctor prepared the following reagents: cardiolipid antigen, isotonic sodium chloride solution, hemolytic system. What other component is needed to stage this reaction?
A . live treponema;
B . sheep red blood cells;
C. complement;
D . antiglobulin serum;
E . diagnostic precipitating serum.
9. In a microslide prepared from a punctate of the patient’s lymph nodes, stained according to Romanovsky-Giemsa, the doctor identified thin microorganisms with 12-14 uniform curls of pale pink color. What infectious disease causative agent 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 using the Romanovsky-Giemsa method revealed convoluted purple bacteria. Which of the following conclusions is correct?
A . the patient was diagnosed T. pallidum;
B . The patient was found to have atypical forms T. pallidum;
C . The patient was diagnosed with non-pathogenic treponemes;
D . the wrong painting method was chosen;
E. -
11. A clinician suspected primary syphilis in a patient. What research material is appropriate to collect to confirm the diagnosis?
A . tissue fluid from chancre and punctate lymph nodes;
B . scraping from skin rashes;
C. cerebrospinal fluid;
D. mucus from nose
E. saliva.
12. Blood was taken from a patient with suspected secondary syphilis for testing. What diagnostic method is appropriate to use to confirm the diagnosis?
A . Vidal reaction;
B . allergy test;
D . Bordet-Gengou reaction
E . bacteriological method
C . indirect immunofluorescence reaction.
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T. pallidum subspecies pallidum is a spiral-shaped bacterium measuring 6-14x0.2-0.3 µm; in crops they can be large. The spiral curls are the same in height, there can be up to 14 of them. Capable of forming L-shapes.
Basic method of reproduction of syphilis- transverse division. The causative agent of syphilis It is not very stable in the external environment and dies when it dries out, but in the cold it persists for up to 50 days. Warming up at a temperature of 40 °C for an hour leads to the loss of pathogenic properties; at 48 °C bacteria die within 10 minutes.
The causative agent of syphilis does not stain well with aniline dyes (hence the name “pale spirochete”). Syphilis bacteria reduce silver nitrate into metallic silver, which gives fabrics a black or dark brown color.
In domestic practice, the Morozov method of silvering is widespread. According to Romanovsky-Giemsa, it is colored pink, and non-pathogenic Treponema- in purple or blue. Burri negative contrast is also used.
Cultural properties of syphilis. Culture of the causative agent of syphilis
Pallid spirochete demanding on cultivation conditions, grows poorly on artificial media; Methods for stable production of cultures are still lacking.
In our country the largest number syphilis strains identified by Kazan microbiologists V.M. Aristovsky and P.P. Geltser.
These "Kazan" syphilis strains along with the Reiter strain, it is used for the production of Ag for serodiagnosis. With long-term cultivation syphilis bacteria adapt to simpler environments (for example, Kitta-Tarozzi) and lose pathogenic properties.
Colonies of syphilis small, appear on the 3-5th day of cultivation.
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