How to choose the right analysis for gonorrhea. Laboratory diagnosis of gonorrhea in women and men Will PCR show chronic gonorrhea

ELISA is one of the most widely used diagnostic methods for various STDs. At the same time, it often happens that suspecting a venereal disease in a patient, the doctor may prescribe several tests at once, such as: seeding tank, PCR and ELISA for gonorrhea. Considering that these laboratory methods of research seem to be absolutely the same to the patient, patients are perplexed about this. But this is not so, the research materials taken in a similar way are analyzed by different methods.

So, ELISA does not detect gonorrhea, this analysis looks for certain markers, which in turn are the waste products of pathogens of various infections. Based on the foregoing, it should be understood that enzyme immunoassay shows a trace of the infection. That is, it is indicative if the gonorrhea pathogen was present in the patient's body and caused an immune response, as a result of which the production of IgG antibodies began. It is the determination of these antibodies that occurs in the process of ELISA analysis.

It happens that enzyme immunoassay indicates the presence of gonorrhea, and PCR and other analyzes of the pathogen are not detected. There may be three reasons for this:

• violation of the research technique;
• the disease was successfully treated, but the trace of the markers in the patient's body was preserved;
• the disease became chronic and other tests did not reveal a small amount of the pathogen.

The second option from the third is easy to recognize by collecting an anamnesis from the patient. After all, gonorrhea does not disappear on its own. There can be no question of any self-healing. This means that if the patient has not undergone drug therapy against gonococci, then he is still sick, just gonorrhea has passed into a chronic latent form.

But it also happens the other way around: PCR can show a positive result for gonococci, and ELISA does not detect the causative agent of gonorrhea. This situation is typical in the case of a protracted course of the disease, when the immune system, weakened by years of fighting gonorrhea, can no longer resist and ceases to produce antibodies.

Among the many infectious diseases known today, those that are sexually transmitted are of great importance. This group includes syphilis, chlamydia, trichomoniasis, gonorrhea. The latter is of great importance. Analysis for gonorrhea is the main method for diagnosing this disease. Gonorrhea is not difficult to cure, but it is dangerous for its complications. These include damage to the skin by the type of eczema, inflammation of the bladder, damage to the musculoskeletal system. In some cases, gonorrhea causes infertility.

This disease is of great social importance. This is due to the fact that the pathogen is easily transmitted sexually from a sick person to a healthy one. In this case, people of any gender and age can get sick. Often, gonorrhea is diagnosed in young people. Every year, tens and hundreds of thousands of people suffer from this disease all over the world. Let us consider in more detail what is the technique for conducting a study on gonorrhea, whether a blood test is useful.

Gonorrhea is an infectious pathology that affects the genitourinary organs, the causative agent of which is gonococcus. Gonococcus is a Gram-negative coccus. In the common people, another name is used - gonorrhea. Gonococci can cause various diseases. These include:

• urethritis;
• inflammation of the rectum;
• throat inflammation;
• salpingitis;
• arthritis;
• conjunctivitis.

Gonorrhea is classified as a sexually transmitted disease. The pathogen can be transmitted not only through sexual contact, but also personal items of a sick person. The incubation period from the moment of infection is from 3 to 7 days. Gonorrhea can occur in acute and chronic form. In the first case, patients complain of a burning sensation in the urethra, pain during urination, frequent urination. With gonorrhea, there is a discharge of a mucopurulent nature.

Often there is a burning sensation in the urethra. An interesting fact is that many patients have no specific symptoms of the disease, and it goes unnoticed. This is especially true for women. In severe pathology, the temperature may rise, nausea or vomiting is observed. In women, the uterus or its appendages may be affected, which contributes to the disruption of the menstrual cycle. As for men, in a complicated course, the testes may be involved in the process, and orchitis or epididymitis occurs.

Diagnosis of gonorrhea

In the presence of gonorrhea in men or women, a specific diagnosis is required. A blood test does not provide accurate information about the pathogen. The doctor cannot make a diagnosis based only on the history of the disease and the patient's complaints. The main purpose of laboratory research is to identify the pathogen. For this purpose, various methods are used: the study of smears, the inoculation of biological material on a nutrient medium, ELISA and polymerase chain reaction (PCR). A blood test is also carried out. The most common and effective way to diagnose is to take a smear for follow-up examination.

In men, a smear is taken from the urethra, and in women - from the vestibule or walls of the vagina, the cervical canal. It must be remembered that a smear for gonorrhea can be taken from the rectum, and if gonorrhea is suspected in children, the material is taken from the separated eyes. In women, a special tool is used to take the material. The optimal time for sampling is at the beginning of the menstrual cycle (on the second or third day). A gynecologist or venereologist uses a mirror when taking material from women.

As for men, the procedure is more painful. In this case, a loop or swab is used for sampling, which is inserted a few centimeters into the urethra. The doctor immediately before taking the material should inform the patient about how to prepare for the analysis. First, before taking a smear, you do not need to urinate for at least 2 hours. Secondly, in order for the analysis for gonorrhea to be reliable, it is not recommended to take antibacterial drugs before it. Thirdly, it is necessary to refrain from sexual intercourse. In addition, it is forbidden to wash before the procedure.

Bacterioscopic examination

Gonorrhea can be detected by microscopy of a native smear. The discharge of the genitourinary organs is applied to a glass slide, while the smear should be very thin. After that, it is stained. The causative agents of gonorrhea perceive aniline dyes well. For staining in laboratory practice, a solution of eosin, methylene blue is used. First, the smear must be fixed and dried, after which a solution of eosin, water, and then methylene blue is applied to it. The final stage is washing off the dyes with water, after which they proceed to microscopy.

Gonorrhea can be diagnosed with a Gram smear. In this situation, gonococci tend to discolor with alcohol. During the study, brighter gonococci will be visible against a pink background under a microscope. Bacterioscopy does not always give an accurate result, especially if the material was taken from the cervix of a woman. There are more reliable and modern diagnostic methods, for example, bacteriological examination.

Sowing on nutrient media

Gonorrhea can be detected by sowing the material and isolating a pure culture of the pathogen. Bacteriological analysis is carried out in the following situations: with negative results of microscopy, when determining the effectiveness of therapy and suspicion of the presence of gonococci in the biological material. For the growth of microorganisms, meat-peptone agar and some other media are used. The disadvantage of bacteriological analysis is that it takes a long time. It takes several days for colonies to grow. The advantage is that this method is the most reliable.

On the first day, the biological material is sown with a loop on a nutrient medium. This is done with strokes. Then the Petri dish is sent to the thermostat. The thermostat sets the optimum temperature (37 degrees) and humidity. On the second day, suspicious colonies are selected. It has been established that colonies of gonococci have their own characteristics. They include colorless or light yellow colonies, small size, shiny and smooth surface, slight bulge. On the third day, pure culture is isolated.

In order to accurately determine gonorrhea, it is possible to evaluate the enzymatic properties of the isolated microorganism. Gonococci can only ferment glucose. With the help of sowing biological material, it is possible not only to make a correct diagnosis, but also to determine the resistance of microorganisms to various antibiotics. This is very important for subsequent treatment.

Other methods of laboratory diagnostics

Very often in laboratory practice, serological methods of research are used. At the same time, in order to establish gonorrhea, RSK is carried out. In the event that there is a mixed infection, then gonococci can be identified by an immunofluorescence reaction. If a blood test is of greatest importance in other infections of the body, then in this situation it is an auxiliary method.

A blood test for gonorrhea reveals signs of inflammation. A blood test is not able to detect gonococci. Enzyme immunoassay is very popular. It will require smears and urine samples. The most reliable and fastest method for detecting gonococci is PCR (polymerase chain reaction) or LCR (ligase chain reaction). PCR is the most specific and sensitive test. Thus, a blood test for suspected gonorrhea is of little value. In most cases, microscopy, inoculation of material on nutrient media and PCR are used.

Neisseria gonorrhoeae is the causative agent of gonorrhea, a specific urethritis that occurs in acute or chronic form. Gonococcus also causes blennorrhea - purulent inflammation of the conjunctiva of the eyes. In laboratory diagnostics, bacterioscopic and bacteriological research methods are mainly used (Scheme 8).

bacterioscopic examination. The material for research should be delivered to the laboratory as quickly as possible in order to avoid autolysis of gonococci, which are very sensitive to temperature changes and cooling. Smears are prepared from the material, stained according to Gram, as well as methylene blue. With a positive result, gonococci are found in smears - gram-negative bean-shaped diplococci located inside leukocytes. A positive bacterioscopic diagnosis is made mainly in the acute form of gonorrhea before the use of antibiotics. In chronic gonorrhea, bacterioscopic examination often gives a negative result, since in these cases gonococci may have an atypical shape in the form of balls or, conversely, very small formations.

In addition, a variety of microflora, leukocytes, epithelial and other cellular elements are found in the preparation.

bacteriological research. The material is inoculated on a Petri dish with special nutrient media - KDS, serum agar, etc. The KDS medium contains nutrient agar with the addition of a certain concentration of casein, yeast extract and blood serum. Crops are incubated at 37 0 for 24-72 hours. Gonococci form clear, dew-drop-like colonies, in contrast to the cloudier streptococci or pigmented staphylococci that can also grow on these sections. Suspicious colonies are subcultured into test tubes on appropriate media to obtain pure cultures, which are identified by saccharolytic properties on media of the “variegated” series (semi-liquid agar with serum and carbohydrates).

Gonococcus ferments only glucose with the formation of acid.

Serodiagnostics. In some cases, they put RSK Borde - Zhangu. A suspension of killed gonococci is used as an antigen. The Borde-Jangu reaction is of auxiliary importance in the diagnosis of gonorrhea. It is positive in chronic and complicated gonorrhea.

Scheme No. 8. Microbiological examination for gonorrhea and blenorrhea

Bacterioscopy - Bacteriological Serodiagnostics

research studies

Stage 1 Smear, staining according to Serum CSC culture

Gram and meth-accurate nutrient-

flax blue agar and KDS

in Petri dishes

stage 2 character of the colonies, reseeding on

Smear, serum stain

Gram nutritious

agar (pure culture)

Stage 3 seeding for determination

"variegated series" of sensitivity

to antibiotics

Independent work

Continue bacteriological examination of pus. To identify a pure culture. Prepare a smear from a beveled MPA, stain according to Gram, microscopically.

Determine the presence of lecithinase. When sowing the culture on JSA in a day, determine the presence of a cloudy zone around the colonies with an iridescent halo.

To study the plasma-coagulase activity of the isolated culture. Inoculate the culture in a test tube with citrate plasma.

To assess the anaerobic fermentation of mannitol, inoculate the isolated culture in a column with mannitol.

Determine sensitivity to antibiotics using the paper disk method.

To study the scheme of microbiological diagnostics of meningococcal infection.

To study the scheme of microbiological diagnostics of gonorrhea.

Microscopically prepared swabs from the urethra of patients with gonorrhea. Sketch. Give a conclusion.

Gonorrhea is an infectious disease caused by gonococcus, sexually transmitted and affecting the mucous membranes of the genitourinary organs.

Symptoms of gonorrhea

The incubation period of the disease, on average, is 1-15 days, most often the first symptoms appear after 3-5. Migration of gonococci from the site of primary contact occurs by lymphogenous and hematogenous routes.

The first symptoms of infection with gonorrhea in men include: the appearance of copious discharge from the urethra (external opening of the urethra) of a mucopurulent nature, with pain, itching and cramps accompanying urination. Allocations occur with pressure on the head of the penis, and can also be spontaneous. In addition, there may be hyperemia and adhesion of the urethra. During sleep, men with gonorrhea may experience painful erections. Sometimes they have a slight increase in temperature to subfebrile indicators.

In most women (about 70%), the symptoms of the disease are not pronounced, in the remaining 30%, mucopurulent or purulent discharge from the vagina, pain during urination and frequent urges may appear. Very rarely, in women suffering from gonorrhea, an inflammatory process of the external genital organs appears, which is accompanied by soreness and swelling of the large and small labia.

Diagnosis of gonorrhea

Diagnosis of gonorrhea is based on questioning and examining the patient, taking an anamnesis, which is necessary to establish the dynamics of the development of the disease, determine the symptoms of the manifestation of manifest forms, detect gonococcus in the urethral discharge, in the rectal contents, in the region of the tonsils and the posterior pharyngeal wall, in the vagina and cervical canal ( in women), in the secretion of the prostate gland (in men).

Diagnosis of the disease in asymptomatic, asymptomatic and chronic forms of gonorrhea will have significant differences. Such a diagnosis is carried out after a preliminary provocation, which can be biological (in this case, gonovaccine is introduced), chemical (Lugol's solution or silver nitrate is introduced), mechanical (metal bougie is introduced), alimentary (salty and spicy provocation, food, alcohol). A variant of the natural provocation of gonorrhea is menstruation.

Varieties of diagnosis of gonorrhea

There are such types of diagnosis of gonorrhea:

1. Bacterioscopic.
   This diagnostic method is carried out in patients (women and men) who have severe symptoms of subacute or acute forms of gonorrhea. Before the analysis, to increase the degree of its reliability, it is necessary that the patient does not self-medicate with antibiotics and does not have a local effect on the vagina and urethra with disinfectant solutions.
2. Bacteriological.
   This diagnostic method is used in patients with severe symptoms in combination with suspected gonococcus on bacterioscopy. A bacteriological analysis for gonorrhea can be used as a diagnostic criterion for the cure of the disease, it can be carried out one week after the end of the course of antibiotic therapy and local treatment (disinfectant solutions). The bacteriological method involves sowing genital secretions on a nutrient medium in order to identify their microflora, while using specially prepared nutrient media. Laboratory material can be: discharge from the cervix, urethra, vagina, as well as the rectum and pharynx.
   An accurate diagnosis of gonorrhea is possible with a minimum amount of discharge available. The accuracy of the method reaches 95 - 100% (a fairly high level of accuracy of the method), however, it has a drawback - the research process is lengthy and takes about a week.
3. Serological diagnostic method.
   This analysis is called the Borde-Gangu reaction, it is carried out in the case of chronic gonorrhea, when the bacteriological analysis is negative. The serological method for detecting gonorrhea is auxiliary.
4. Immunofluorescence analysis (PIF).
   Using this diagnostic method, it is possible to detect gonococcus in the early stages of the disease, this is important in cases where there is a combination of gonococcus and other microorganisms, such as pale treponema (gonorrhea is combined with syphilis).
5. Linked immunosorbent assay.
   Allows you to determine the presence in the secretions of resistant L-forms of gonococcus, or vice versa, non-viable strains.
6. Polymerase chain reaction (PCR).
   PCR is a DNA test for gonorrhea - a method of genetic identification of gonococcus. This method has the highest sensitivity and specificity, the diagnosis of gonorrhea by this method reaches 98% in men and 89% in women. The results of diagnostics using PCR are ready in 1-2 days. However, this method is quite expensive and not all patients can afford it.

gonorrhea treatment

Gonorrhea is treated in a hospital after preliminary diagnosis and laboratory detection of gonococcus. You cannot self-medicate. Acute and subacute forms of gonorrhea are treated with antibacterial drugs that have bacteriostatic and bactericidal action. Asymptomatic, asymptomatic, chronic and complicated forms of gonorrhea are treated in a complex manner.

Today, gonococcal infection is treated with cephalosporins (cefotaxime, ceftriaxone) and fluoroquinolones (ofloxacin, ciprofloxacin), spectinomycin. The modern use of fluoroquinolones for the treatment of gonorrhea is due to the increased resistance of the pathogen. Synthomycin, streptomycin, biomycin, chloramphenicol are also effective (at the discretion of the doctor). Sometimes sulfanilamide preparations (sulfadimezin, norsulfazol, sulfazin) are prescribed. Preparations for treatment are chosen by the doctor, taking into account the history (presence of allergies) and the sensitivity of the gonococcus to antibacterial drugs. In addition, patients are shown immunotherapy (drugs that increase resistance to infection), physiotherapy (ionization, diathermy, paraffin, ozocerite).

In the case of past gonorrhea, immunity to re-infection is not formed, while each subsequent infection proceeds in a more severe form and has a large number of complications. If acute gonorrhea is not treated, or treated incorrectly, the disease gradually becomes chronic, which complicates and lengthens the treatment process. In the treatment of all forms of gonorrhea, patients are strictly forbidden to drink alcohol, salty and spicy foods. Active sports are also not recommended: skiing, cycling, skating, patients should not lift heavy objects, in addition, sexual intercourse is prohibited during the course of treatment. At the end of treatment, patients are observed for 2-3 months in the dermatological dispensary. After the end of the control observation, the patient is removed from the register.

Prevention of gonorrhea is based on timely diagnosis and treatment. Regular preventive medical examinations of employees of various professions increases the detection of the disease. Examination for gonorrhea is also subject to women who applied for termination of pregnancy, pregnant women and women with trichomoniasis. Compliance with the rules of personal hygiene and the exclusion of sexual intercourse without the use of a condom reduces the risk of the disease. A patient is considered cured of gonorrhea if, on the second and fourteenth days after the end of treatment, microscopic examination of scrapings from the urethra or vagina does not contain gonococci.

Gonorrhea is an insidious disease. If we are talking about the female part of the population, then they may not manifest it at all, proceeding chronically and almost asymptomatically. At the same time, the risk of infecting a partner is extremely high, because such a situation is very common when a woman herself does not even suspect that she has gonorrhea. That is why it is so important to identify this disease in time and correctly. There are several ways to diagnose gonorrhea, each of which we will consider in detail. However, we will not dwell on clinical methods, because. The article is devoted specifically to the laboratory diagnosis of gonococcal infection.

microscopic examination

The very first thing that needs to be prepared in order for this diagnostic method to succeed is the material in which the presence of the pathogen must be determined. With severe symptoms and a large amount of discharge in men, a smear is taken for gonorrhea from the mucous membrane of the urethra and rectum. In women, the material is taken with the help of an imprint from the outlet of the urethra, rectum - it is enough just to lean a glass slide against them so that the secretions from these organs fall on it - of course, if we are talking about clinically pronounced gonorrhea.

However, in order to more accurately identify gonorrhea, standardized sampling methods are used. As for men, the discharge from the urethra is taken from them using a special swab moistened with physiological saline. If there is little discharge, the urethra is massaged from top to bottom.

In women, a swab for gonorrhea - discharge from the urethra - is taken using a special tool - Volkmann's spoon - or a small swab. Material from the cervical canal can be taken with vaginal forceps and a special loop.

After taking the material for analysis for gonorrhea, the process of its preparation, processing and coloring begins. With the help of a special dye - methylene blue (or even ordinary brilliant green), the material fixed to the glass is stained blue or green - bacterial cells absorb the dye and become visible under a microscope. Another method of staining is also used - according to Gram. Diplococci - the causative agents of gonorrhea - turn pink, while the rest of the cocci turn blue. Gram stain is perhaps one of the most reliable ways to diagnose gonorrhea.

Bacteriological (cultural) research

Bacteriological analysis for gonorrhea is carried out less often - only in cases where microscopy fails to accurately identify the pathogen, as well as in other controversial situations. The secretions obtained from the patient are then sown on a medium with nutrients (this is usually ascites agar - a medium consisting of natural ascitic fluid taken from patients with liver diseases, and agar - a natural polysaccharide). After five to seven days at a constant temperature, check whether there is growth of colonies, and if so, the colonies are identified macroscopically, indicative testing is carried out, and finally, the obtained pure culture is microscopically obtained.

Serological methods for diagnosing gonorrhea

Serological methods for diagnosing gonorrhea involve the direct detection of antigens in the patient's blood (the antigens of the pathogen are proteins of its shell and polysaccharide molecules - particles of flagella, pili, as well as enzymes and waste products). For the diagnosis of gonorrhea, RSK is widely used - the complement fixation reaction, which in this case has its own "personal" name - the Bordet-Jargoux reaction.

Diagnosis of gonorrhea is carried out using this method as follows: the patient's blood serum is heated for half an hour at 56 degrees - due to this, complement proteins in it are destroyed. Then, pre-prepared gonococcal antigens (the smallest particles of microbes grown in the laboratory) are added to the serum. If there are antibodies to gonococci in the patient's serum, they are adsorbed on the surface of the antigen. Smaller antibodies, as it were, stick around large pieces of bacterial proteins.

The next stage of the reaction is the addition of artificial complement (blood serum obtained from laboratory animals) to the mixture. We take into account that the complement is activated only if the solution contains both antibodies and antigens, and the more of them, the more fully it reacts. At the last stage, a suspension of sheep erythrocytes is added to the analyzer, which were in direct contact with hemolytic serum for half an hour. The more unused complement will be in the mixture, the more intense hemolysis is, and vice versa, the more complete the complement is used up, the slower the rate of hemolysis.

Immunofluorescence

The essence of this method is not too complicated - first, a preparation is made from the material taken from the patient for examination under a microscope - in other words, the secretions are applied to a glass slide and heated over the flame of an alcohol lamp. The second stage of processing preparations is their coloring with methylene blue and, importantly, with a special composition that has the property of fluorescing (emitting light). Then the glass slide is placed on the microscope stage and examined by directing light on it - the microorganisms are clearly visible in the form of luminous spherical formations.

Linked immunosorbent assay

The essence of ELISA for gonorrhea (and not only) is as follows. The patient's material is taken (most often blood) and placed in special containers, where it settles for some time and reacts with antibodies deposited on the walls of the containers. Then the material is poured out, the containers are thoroughly rinsed - in this way all “extra” antigens that have not contacted with antibodies on the walls are removed. And, finally, the most important stage of the study is the addition of an enzymatic preparation that has the ability to change its color depending on the amount of unbound antibodies. Everything, by the method of solution colorimetry, it is possible to calculate the concentration of antibodies and the corresponding concentration of antigens.

To detect gonorrhea, standardized kits are used, for example, Gonozyme. The sensitivity of the ELISA method for gonorrhea is high - about 95%, which makes it easy to gonorrhea in both men and women, and you can examine both blood and urine and discharge from the genitals.

polymerase chain reaction

For research by PCR (polymerase chain reaction - ultrasensitive analysis for gonorrhea), material from the urethra and cervical canal is used. The sensitivity of the method in detecting gonococci in men is about 98%, in women - 89%.