Gonococci

Gonorrhea (Greek gonos - seed and rhoe - efflux) is an infectious disease caused by gonococcus and characterized by an inflammatory lesion of predominantly mucous membranes of the urogenital organs.

The causative agent of gonorrhea - Neisseria gonorrhoeae, discovered in 1879 by A. Neisser - a bacterium, is a coccus resembling coffee beans or kidneys, located in pairs, the concave sides of the cells facing each other. Dimensions of 0.7-0.8, sometimes 1.25-1.60 microns. The division of cocci occurs in the same plane. With electron microscopic examination, a mucous capsule-like formation with a thickness of 0.35-0.40 μm is found around the gonococcus, thanks to which the cocci do not touch each other: there is a gap between them. Gonococcus gram-negative, they well perceive the main aniline dyes. To stain preparations from gonorrhea pus, methylene blue is more often used, since the bean-shaped form of the gonococcus is better detected, and in contrast to other similar diplococci, Gram stain is required. Phagocytosis of gonococci is incomplete, complete phagocytosis is observed in monocytes and histiocytes. Gonococci do not have flagella, capsules, spores and pigment do not form. The content in the DNA of G + C is 49.5-49.6 mol%. On meat-peptone agar, they grow poorly, reproduce better on media containing serum, ascites fluid or blood. Hemolysis does not cause. For the growth of gonococci it is necessary to have iron in the medium. The addition of starch, cholesterol, albumin or coal particles to dense nutrient media promotes growth, and the addition of Ca ++ ions increases the viability. The optimum temperature for growth is 35-36 ° C, but the growth occurs in the range of 30-38.5 ° C, the optimal pH is 7.2-7.6 Gonococci are strict aerobes, but in primary crops it is better to grow with a certain increase in the C02 content.

D. Kellog and others have revealed the relationship between the virulence of gonococci and the nature of the colonies formed by them. Virulent gonococci for humans, isolated from patients with acute gonorrhea, have saws and form small, in the form of drops, shiny colonies designated as T1 and T2. Colonies of large size, flat and dull (T3 and T4), form nonvirulent and pylorus-free gonococci. Of carbohydrates, gonococcus ferment only glucose to form an acid without gas. Among gonococci there are different antigenic populations. This is confirmed by the lack of people's immunity to re-infection. In accordance with this, attempts were made to develop a universal serological classification of gonococci. In particular, for albuminous antigens of the outer membrane gonococci are distributed into 16 serotypes. In addition, gonococci differ in their lipopolysaccharide antigens. An antigenic relationship of gonococci with other types of Neisseria has been found, most closely with meningococci. Gonococci synthesize bacteriocins, which can also be used for their typing.

[1], [2], [3], [4], [5], [6], [7],

Factors of pathogenicity of gonococci

Exotoxins in gonococci have not been detected. The main factors of pathogenicity are saws, with which gonococci carry out adhesion and colonization of epithelial cells of the mucous membrane of the urogenital tracts, and endotoxin (lipopolysaccharide) released during the destruction of gonococci.

[8], [9], [10]

Resistance of gonococci

Gonococci have a weak resistance to external influences: they quickly die under the influence of direct sunlight, UV light, drying, high temperature (at 40 "C rapidly lose vitality.) Various chemicals, such as silver salts, mercury, and conventional disinfectants kill for a short time, for example, silver nitrate in a dilution of 1: 5000 kills gonococci within 1 min, and at a dilution of 1:10 000 - in 10 min.

Postinfectious immunity

The transferred gonorrhea does not leave immunity to repeated infection, but this circumstance is probably due to the fact that the immunity has a type-specific character, since antibodies are found in the blood of the recovered patients in sufficiently high titres.

Epidemiology, pathogenesis and symptoms of gonorrhea

For animals, the gonococcus is not pathogenic. The only source of infection is a person infected with gonococci. Infection occurs mainly sexually, sometimes through household items. The main habitat of gonococci is the surface of the mucous membrane of the genitourinary tract, less often - the rectum and pharynx. The entrance gate for men is the mucous membrane of the urethra, in women - most often the mucous membrane of the vestibule, urethra and cervix. In case of penetration through the epithelial barrier, gonococci can spread to the surrounding tissues: the glands of the urethra and the cervix, the prostate, seminal vesicles, uterus and fallopian tubes, enter the blood, penetrate the synovial membranes of the joints, heart and other organs, inflammatory processes, and sometimes septicemia. Under certain conditions, gonococci can penetrate the conjunctiva and cause ophthalmia (inflammation of the eye mucosa - blenorrhea). This is most often observed in children born to infected gonorrhea by mothers. The incubation period of gonorrhea varies from one day to 2-3 weeks. And more, but most often is 3-4 days. Symptoms of gonorrhea allow us to distinguish two basic forms of gonorrhea - acute and chronic. A typical symptom of acute gonorrhea is acute purulent inflammation of the urethra, glands of the lower part of the genital organs and cervix in women, accompanied by painful sensations, as well as abundant purulent discharge from the urethra. For chronic gonorrhea, a typically milder manifestation of clinical symptoms associated with the location of the pathogen.

[11], [12], [13], [14], [15], [16], [17],

Diagnosis of gonorrhea

Bacterioscopic - the material for investigation is purulent discharge of the urethra, vagina, cervix, prostate and other organs affected by gonococcus, as well as urine sediment and strands. As a rule, smears are stained by Gram and methylene blue. Gonococci are detected by three characteristic features: gram-negative coloring, bean-shaped diplococci, intracellular location. To detect gonococci in the smear, the method of direct and indirect immunofluorescence is also used. However, under the influence of chemo-and antibiotic therapy, as well as in chronic gonorrhea, morphology and Gram staining in gonococci can vary, in addition, they can be very few in the smear. Often, chronic gonorrhea in smears shows gonococcus type Asha: the cells of the diplococcus have an unequal magnitude and shape. In such cases, a bacteriological method is used. For this purpose, the test material is sown on special nutrient media. The isolated culture is identified taking into account the characteristics characteristic of gonococcus. It should be borne in mind that if in grafts from a purulent material the gonococci were stained positively, then in smears from the grown culture they have a gram-negative coloring restored. All gonococci in 24-hour culture have almost the same value, the form of diplococci or cocci, but after 72-96 h the culture becomes polymorphic and the cells are stained Gram unevenly. With chronic gonorrhea for diagnosis, RCC or an allergic skin test with a special gonococcal allergen can be used.

[18], [19], [20], [21], [22], [23]

Treatment of gonorrhea

Treatment of gonorrhea is carried out with antibiotics and sulfanilamide preparations. Good results are obtained using various penicillins, tetracycline drugs and other antibiotics. Since gonococci are resistant to them, it is necessary to determine to which antibiotics the gonococci isolated from the patient are sensitive.

Prevention of gonorrhea

Specific prevention of gonorrhea is not developed. General prophylaxis is the same as with other sexually transmitted diseases, since infection occurs mainly through sexual contact. To prevent blenorrhea in newborn children, 1-2 drops of a 2% solution of silver nitrate or (especially in premature infants) 2 drops of a 3% solution of penicillin oil to which the gonococci are very sensitive and die from it quickly (after 15-30 minutes) are injected into the conjunctival sac in the conjunctival sac. Min.).