Onset within 4-7 days.
Chlamydia infection can lead to many diseases. Urinary tract infection is usually called nongonococcal urethritis (NGU). In the detection of non-gonococcal pathogens, the detection rate of Ureaplasma urealyticum accounts for 20%-40%.
pathology
[pathogen]
Mycoplasma is the smallest microorganism that can grow and reproduce in inanimate media.
Mycoplasma has a variety of shapes, basically spherical, rod-shaped or filamentous, and the colony is the size of a needle tip, so it is also called mycoplasma minutum. Mycoplasma is characterized by no cell wall and precursors and few organelles. The G+C content of DNA is low, and there is a very small genome in bacteria, with a molecular weight of about 45× 108, and the cell size of bacteria is about 0.2-0.3μm, rarely exceeding 1.0 μ m ... It is composed of three layers of membrane structure and hair structure composed of protein and lipids. Mycoplasma divides and reproduces in various forms. Mycoplasma staining is generally difficult to dye, but Giemsa staining is very shallow and Gram staining is negative. Mycoplasma can grow in chick chorioallantoic membrane or cell culture. Cultivate with culture medium. Nutritional requirements are higher than bacteria. Because it has no cell wall, it is not sensitive to antibiotics that affect the synthesis of cell wall, such as penicillin. Antibiotics acting on ribosomes, such as erythromycin, tetracycline, kanamycin, streptomycin, chloramphenicol, etc., can inhibit or affect the protein synthesis of mycoplasma and kill mycoplasma. Mycoplasma has poor heat resistance. Usually it can be inactivated at 55℃ for 15 minutes. Carbonic acid is easily killed by Lysol. Urea is put into the culture medium, and manganese sulfate is used as the indicator, which is easy to distinguish from other mycoplasma.
It is widely distributed in nature, with more than 80 species. Mycoplasma related to human beings include Mycoplasma pneumoniae (Mp), Mycoplasma hominis (MH), Ureaplasma urealyticum (UU decomposes Ureaplasma urealyticum) and Mycoplasma genitalium (MG).
Mycoplasma pneumoniae causes pneumonia. At present, seven kinds of mycoplasma have been isolated from human urogenital tract, among which Ureaplasma urealyticum has a high isolation rate, followed by Mycoplasma hominis, which is related to urogenital diseases. Mycoplasma hominis (MH), Ureaplasma urealyticum (UU) and Mycoplasma genitalium (MG) can all cause urogenital tract infections.
Ureaplasma urealyticum is a prokaryotic microorganism, rod-shaped, with a size of 125-250 nm and a molecular weight of 4.5* 108. It is highly polymorphic and has no hard cell wall. It can proliferate in sterile culture and produce urease to decompose urea. Specific antibodies can inhibit its growth, because it lacks hard cell membrane, is resistant to penicillin, has affinity for cell membrane, and needs steroids for growth and reproduction. Tetracycline, erythromycin and spectinomycin are effective. Ureaplasma urealyticum can not be found in the reproductive tract of infants or women who have no sexual contact. The more chaotic the sexual life, the higher the positive rate of this mycoplasma. Mc Donald 1982 reported that among 587 patients with symptoms of acute urethritis, 209 cases (36%) were isolated from middle urine.
Mycoplasma hominis has weak resistance to external environment and can be killed at 45℃ 15min. Sensitive to soap, alcohol, tetracycline and erythromycin.
pathogenesis
Mycoplasma can only attach to the receptors on the surface of epithelial cells of respiratory tract or urogenital tract, and does not enter tissues and blood. The causes of cell damage caused by mycoplasma are as follows: (1) Mycoplasma adhering to the surface of host cells absorbs nutrients from cells and obtains lipids and cholesterol from cell membranes, causing cell damage; Toxic substances produced by mycoplasma metabolism, such as Mycoplasma lysolyticum, can produce neurotoxins and cause cell membrane damage; Ureaplasma contains urease, which can hydrolyze urea to produce a large amount of ammonia, which is toxic to cells. Mycoplasma can not only adhere to the surface of cells and macrophages, but also adhere to the surface of sperm, thus preventing sperm from moving. Neuraminidase-like substances produced by mycoplasma can interfere with the combination of sperm and eggs. This is one of the causes of infertility caused by mycoplasma infection.
In animal experiments, it was found that mouse peritoneal macrophages could kill mycoplasma, but neutrophils had little effect. In vitro, IgG 1 and IgG2 antibodies have a conditioning effect. It can strengthen the killing effect of macrophages on mycoplasma.
Diagnosis and differential diagnosis
laboratory diagnosis
Laboratory diagnosis of mycoplasma infection
(1) Clinical diagnosis
Those who have a history of unclean sexual intercourse, urethral and vaginal secretions and burning urination, but exclude the possibility of other pathogens, take a smear of urethral or cervical secretions, and see polymorphonuclear leukocytes ≥5 under the microscope of 1000 times, which can be used for preliminary diagnosis.
(2) Experimental diagnosis
The laboratory diagnosis of mycoplasma infection is mainly mycoplasma culture and serological identification, and gene diagnosis is mainly used at present.
1. Mycoplasma culture:
A. collect specimens, usually urogenital specimens or brushes, and a few take prostate fluid, semen, joint fluid, or fallopian tube and rectal biopsy. In recent years, centrifugation of initial urine samples has been used to replace urethral swabs. When taking the swab, insert the swab into the male urethra for 2-4cm and rub it hard. This method is easy to cause urethral injury and secondary infection. Be careful when using it. Women need to clean the junction of cervical squamous epithelium and columnar epithelium first, and collect cervical samples with cell brush, which can increase the number of infected cells and is more sensitive than cotton swabs.
B Common culture medium is Niuxin cream or peptone, containing 1% fresh yeast cream, 10-20% animal serum and 0.5% sodium chloride. Glucose and arginine can also be added to promote the growth of MH and MG, urea can be added for UU metabolism, and penicillin can be added to inhibit miscellaneous bacteria.
2. Serological identification method: agar diffusion method is the most commonly used method, that is, mycoplasma is inoculated on agar plate. Then put the filter paper soaked with proper serum on the surface of agar to see which one can inhibit the growth of mycoplasma. The colonies on the agar surface can also be stained with fluorescent antibody and observed by emission fluorescence microscope. The advantage of this method is that colonies that originally grew on the agar surface can be used without transmitting mycoplasma.
Serological diagnosis test: Enzyme-linked immunosorbent assay (ELISA) has high sensitivity; Micro-immunofluorescence assay (MIF) has the characteristics of rapidity.
3. Gene diagnosis: The sensitivity of diagnosing mycoplasma with DNA probe is slightly poor, but the specificity is high, and the sensitivity and specificity of diagnosing mycoplasma with PCR are high. Specific detection aspects are as follows:
(1) specimen processing
1. The cervical canal was taken and the male urethra was taken. Put the sterilized platinum ear into the cervical canal or urethra for about 1cm, rotate it several times, stay for about 30 seconds, and take it out from the buffer after the specimen.
2. Extraction of ureaplasma urealyticum DNA;
The curettage of cervical canal or urethra was placed in TES buffer (50 mol/L Tris-HCl, 50mmol/L NaCl, 100mmol/ L EDTA, pH 8.0) containing 0.5%NP-40, 0.5%Tween20, 1%SDS and 2mg/ml protease K. DNA was extracted with chloroform, precipitated with ethanol, and the precipitate was dissolved in 20μl TE buffer (100mmol/L Tris-HCl, 1mmol/L EDTA, pH 8.0).
(2) Primer design
Primers are derived from Ureaplasma urealyticum, urease gene sequence:
uu 1:cagatacattaacgaagcagg( 16 13- 1635)
UU2:GTGGTGACATACCATTAAC( 1837- 18 19)
(3)PCR amplification
The traditional method is that the reaction volume is 100μl, containing 20μ l of 5x reaction buffer, 2 μ l of FD-dNTP polymerase, 200μmol/L of tetradntp and 25 μm ol/L of primer pair. The above ingredients were prepackaged in a 0.5 ml centrifuge tube at -20℃. Add 2 μ l template DNA, centrifuge briefly, and cover with 100μl mineral oil. Now the reagent has been commercialized, the reaction volume is 25μl, and the single tube has been subpackaged, as long as template DNA is added. Set the DNA amplifier to 40 amplification cycles. Each cycle includes three steps: denaturation at 90℃ for 45s (denaturation for 2min in the first cycle), annealing at 55℃ for 30s, and extension at 72℃ for 40s (extension at 72℃ for 5min in the last cycle). Every amplification should be controlled by yin and yang.
(4) Detection of amplified products
1.5% agarose gel electrophoresis detection: PCR amplification products of10ul were subjected to 1.5% agarose gel electrophoresis and 0.5μg/ml ethidium bromide staining, and the results were observed by ultraviolet transmission instrument with pgem-3zf (+) DNA-hae Ⅲ as the molecular weight standard.
Mycoplasma treatment
Treatment: The treatment method is basically the same as chlamydia treatment. Doxycycline 100mg orally, twice a day for 7- 14 days or azithromycin 1g in a single dose, with a half-life of 60 hours, can maintain the effective concentration for 5 days once; Fluzinic acid 0.2, taken orally twice a day, for 7- 14 days.