Tests for chlamydia: types, preparation, decoding
The content of the article:
- Indications for analysis for chlamydia
-
Types of tests for chlamydia
- Culture analysis
- Cytological examination of a smear
- Immunofluorescence reaction (RIF)
- Immunoassay (ELISA)
- Polymerase chain reaction (PCR)
- Express diagnostics
- Preparation for analysis for chlamydia
- Chlamydia and chlamydia
Analysis for chlamydia as part of a preventive examination plays an important role. This is due to the fact that chlamydia is often asymptomatic. Tissue samples, blood, urine and other biological fluids can serve as research material.
Chlamydial infections are a group of infectious diseases caused by chlamydia. Bacteria of this kind affect the organs of the genitourinary, respiratory, cardiovascular, visual, musculoskeletal systems.
Indications for analysis for chlamydia
Examination for chlamydia is indicated in the following cases:
- preventive examination;
- signs of a genital infection;
- planning pregnancy;
- a history of complicated pregnancy;
- obstetric registration;
- inflammatory diseases of the genitourinary organs;
- absence of pregnancy for 2-3 years of regular sex life;
- monitoring the effectiveness of therapy for chlamydia;
- persons whose sexual partners have chlamydia.
One of the analyzes for chlamydia is inoculation of material on nutrient media
Types of tests for chlamydia
Chlamydia diagnosis is carried out in several directions.
Culture analysis
Study of the biomaterial by inoculation, isolation of the culture of the pathogen and determination of its sensitivity to antibiotics. During the analysis, the chlamydial isolate is used to infect sensitive cells. Then a growth medium is added to them, which contains an antibiotic. Infected cell cultures were incubated at +36 on C for five days. Antibiotic sensitivity is determined depending on the suppression of infection. Sowing on chlamydia is used to assess the effectiveness of antibacterial treatment; the disadvantages of the method include the laboriousness of the process and the duration of preparation.
Cytological examination of a smear
The method is informative only in acute forms of the disease. Epithelial scrapings serve as clinical material for research. In the course of the study, the biomaterial is exposed to fixing agents and staining. Under the influence of reagents, drugs are detected under a light microscope.
Immunofluorescence reaction (RIF)
Identification of chlamydial antigens using a fluorescent microscope. The method is based on the property of antibodies to differ from each other by the brightness of the luminescence, while the inclusions of chlamydia stand out against the background of the cytoplasm of the cells. This method is not sensitive enough in the asymptomatic course of the disease.
Immunoassay (ELISA)
A method based on the detection of specific antibodies to chlamydia in the test samples. Allows you to determine the phase of the disease, to evaluate the effectiveness of antibacterial treatment. Thus, the production of IgM antibodies to Chlamydia trachomatis is a marker of the acute stage of the process. With the progression of the disease and its transition to a chronic form, IgA antibodies appear, then IgG.
The interpretation of the enzyme immunoassay is presented in the table.
| Disease stages | IgM | IgA | IgG |
| Sharp | 50-3200 | 50-1600 | 100-6400 |
| Chronic | Up to 200 | Less than 50 | 100-1600 |
| Aggravation | Less than 50 | 50-400 | 100-51200 |
| Recovery | Less than 50 | Less than 50 | 100-400 |
Polymerase chain reaction (PCR)
A method for identifying DNA fragments of the pathogen, which allows you to confirm the presence of a foreign microorganism in the body with an accuracy of 90-95% and determine what kind of microorganism it is. Samples of tissue, blood, urine and other biological fluids can be taken for analysis. In women, epithelial scrapings are taken from the vagina, urethra, cervix. In men, a smear from the urethra, prostate secretions, ejaculate are used. If the eyes are affected, scraping from the conjunctiva is examined. To exclude rheumatic lesions of the osteoarticular system, the articular fluid is examined.
Special devices are used - amplifiers for DNA multiplication. When the amount of DNA is sufficient, it is determined whether the sample contains DNA fragments characteristic of the infectious agent. Evaluation is carried out by electrophoresis or using labeled DNA fragments. Normally, the genetic material of chlamydia is not found.
The PCR result can be positive or negative. A quantitative assessment in dynamics allows you to determine the activity of the pathogen and the effectiveness of the therapy.
Express diagnostics
For express diagnostics, immunochromatographic tests are used, the action of which is based on the use of fluorescent markers, while the presence of chlamydia DNA in the sample is determined already in the reaction tube.
To identify chlamydia allows an integrated approach. It is important to consider how much analysis is done. As a rule, after receiving the results of PCR (usually ready 4 days after delivery), additional studies are prescribed - culture culture and enzyme immunoassay. The results of the study are individual for different types of infection; only a doctor should deal with their interpretation and determination of the nature of treatment.
Preparation for analysis for chlamydia
How is the material taken for research and how to pass it correctly?
A blood test for chlamydia is performed using venous blood, which is taken in the morning on an empty stomach.
Preparation for the study includes abstaining from alcohol, fatty and salty foods, smoking for a day. It is recommended not to urinate for several hours before taking a biological sample from the urethra.
Before culture examination, it is necessary to stop taking antibiotics and uroseptic drugs for 30 days. In immunocytological studies, antibacterial drugs are canceled in 14 days.
On the eve of PCR, women are advised to abandon douching, hygiene procedures with antibacterial soap, and the use of vaginal suppositories. Before collecting material, men need to stop using medicines to increase potency.
Chlamydia and chlamydia
Three types of chlamydia infect humans - C. trachomatis, C. Psittaci and C. pneumoniae. The localization of the pathological process depends on the type of bacteria. Chlamydia trachomatis causes the urogenital form of chlamydia.
Chlamydiae are intermediate between bacteria and viruses
Chlamydiae are intermediate between viruses and bacteria. Like viruses, they multiply on tissue cultures and are capable of long-term intracellular parasitism without pronounced clinical manifestations and conflicts with the host's immune system. Under the influence of unfavorable factors for them, chlamydiae are transformed into an inactive L-form, and during the period of immunosuppression they awaken and begin to actively multiply (the so-called reversion of L-forms to their original forms). At the same time, like bacteria, chlamydiae contain DNA and RNA molecules, have ribosomes and a cell membrane, and multiply by binary fission.
According to the characteristics of the genetic material, there is a similarity with mycoplasma, ureaplasma and haemophilus influenzae.
Infection routes:
- sexual - with unprotected sexual intercourse;
- vertical (from mother to newborn baby) - infection of the fetus through the placenta during pregnancy or during childbirth;
- contact and household - through common household items, kisses.
The significant prevalence of chlamydial infection is due to the asymptomatic nature of the course of the disease. The appearance of the first clinical signs and the development of symptoms (vitreous discharge from the urethra, itching, pain and stinging during urination, temperature drops, signs of intoxication) depends on the state of immunity. After a while, the symptoms of chlamydia usually disappear, the disease goes into a chronic stage with periods of exacerbation. This form of infection is called persistent.
Chlamydia in the body causes many complications, including urethritis, prostatitis, endometritis, salpingo-oophoritis, pneumonia, conjunctivitis, joint diseases, damage to the cardiovascular system. Chlamydia trachomatis can cause infertility in men and women, miscarriage, and the development of chlamydia in children.
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
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