Analysis of microflora from the vagina

General clinical study of the material from the vagina

Examination of the vaginal discharge is performed to assess the nature of the microflora and to identify the inflammatory process, as well as to identify atypical cells and evaluate the production of sex hormones (the "hormonal mirror"). The material for cytological diagnosis is obtained in various ways: by aspirating and scraping the contents of the posterior vaginal fornix, the cervical canal or obtaining smears of prints.

The microflora of the vagina

In the diagnosis of inflammatory processes of the genital tract, the most important role is played by the study of the microflora of the separated. From modern positions, the normal microflora of the genital tract is considered as a set of microbiocenoses occupying numerous ecological niches on the skin and mucous membranes. Microorganisms that make up the normal microflora of the vagina, are among themselves in a variety of relationships (neutralism, competition, commensalism, synergism, parasitism, etc.). The change in the number of certain microorganisms in the corresponding biotope or the appearance of bacteria that are not characteristic of this habitat serves as a signal for reversible or irreversible changes in the corresponding link of the microecological system. A feature of the normal microflora of the genital tract in women is its diversity.

Facultative lactobacilli predominate in the vaginal content of women with a regular menstrual cycle and pregnant women, but are virtually absent in girls in the prepubertal period and in postmenopausal women. The number of lactobacilli in the vagina of healthy women is 10 ⁵ -10 ⁷ cfu / ml. The production of estrogens in women of reproductive age increases the glycogen content in the vaginal epithelium. Glycogen is metabolized to glucose and subsequently lactobacilli to lactic acid. It provides a low level of pH (less than 4.5), promotes the growth of acidophilic microorganisms, in particular lactobacilli. In addition to lactobacilli, the vaginal biocoenosis contains more than 40 species of other bacteria, but their share does not exceed 5% of the total number of microorganisms. In healthy non-pregnant women, the rank sequence of bacterial species is as follows: lactobacilli, bifidobacteria, peptococci, bacteroides, epidermal staphylococci, corynebacteria, gardnerella, mobilungus, mycoplasma. The ratio of anaerobic flora to aerobic is 10: 1.

Species composition of the normal microflora of the vagina

Microorganisms	Content, detection frequency
Total number of microorganisms	10 5 -10 7 / ml
Facultative lactobacilli	More than 90%
Other microorganisms:	10%
Staphylococcus epidermidis	36.6%
Bifidobacteria	50%
Candida albicans	25% (in pregnant women up to 40%)
Gardnerella vaginalis	40-50%
Ureaplasma hominis	70%
E. Coli	In a small amount
Staphylococci and streptococci	In a small amount
Anaerobic microflora (bacteroides, peptostreptococci, clostridia)	In a small amount

The normal bacterial flora performs an antagonistic role, preventing the invasion of pathogenic microorganisms, and any invasion of the healthy epithelium is almost always accompanied by changes in the microflora of the vagina.

To assess the state of the microflora of the vagina, a bacteriological classification of 4 degrees of purity was used for a long time in clinical practice, taking into account the number of lactobacilli, the presence of pathogenic bacteria, leukocytes, epithelial cells.

• I degree. In smears, epithelial cells and a pure culture of facultative lactobacilli. The reaction of the vaginal contents is acidic (pH 4-4.5).
• II degree. A small number of leukocytes, optional lactobacillus rods are smaller, there are other saprophytes, mainly gram-positive diplococci, the content reaction remains acidic (pH 5-5.5).
• III degree. A large number of epithelial cells, leukocytes. Optional lactobacilli in a small amount, a diverse coccal flora; the reaction is weakly acidic or basic (pH 6-7.2).
• IV degree. Epithelial cells, many leukocytes, a diverse pyogenic flora in the complete absence of the vaginal coli, the reaction is basic (pH above 7.2).

At the present time, the conventionality of this classification and its insufficient informativeness are obvious. It does not take into account the variety of normal microflora species, their mutual relations, as well as the possible presence of pathogenic pathogens such as gonococci, trichomonads, fungi, chlamydia, etc.

Infringement of a parity of the maintenance of various kinds of microorganisms or a specific structure of their associations leads to occurrence of inflammatory processes of a vagina. The mechanisms that change the normal vaginal ecosystem include: hormonal factors that determine the glycogen content in epithelial cells; microbial antagonism; a violation of the immune system; sexual behavior.

For the correct interpretation of pathological changes in inflammatory processes in the genital tract of women, it is important to know the cytomorphological features of the normal mucous membrane of the vagina.

The epithelium of the vagina (multilayered flat) during the menstrual cycle is subject to cyclic changes under the influence of sex hormones. In the multilayered flat epithelium of the vagina, the following layers can be distinguished: superficial, intermediate, external basal and internal basal. In the first days after menstruation, approximately a third of the vaginal epithelium remains, and then again during the menstrual cycle.

In smears from the vagina, four types of epithelial cells are distinguished.

• Cells of the surface layer are large (35-30 μm) polygonal, the nucleus is small (6 μm), pycnotic. Cells are more often located separately. These cells are present in large numbers from the 9th to the 14th day of the menstrual cycle.
• The cells of the intermediate layer are smaller in size (25-30 microns), the shape is irregular, the core is larger, round or oval. The cells are often arranged in layers. Present in all phases of the menstrual cycle.
• Parabasal layer cells are small in size, round in shape, with a large round central nucleus. Present in small amounts only during menstruation and appear in smears during menopause or amenorrhea.
• Cell basal (or atrophic) less parabasal, rounded, with a large nucleus, the ratio of the nucleus and cytoplasm is 1: 3. Appear in the menopause and postnatal amenorrhea.

In vaginal smears, in addition to the epithelial cells, red blood cells can be present (they occur with minor tissue damage), leukocytes in the amount of 6-8, and after ovulation up to 15 in the field of vision, they enter the discharge or by migration through the vaginal wall, or as an integral part inflammatory exudate.

The mucous membrane of the cervical canal is covered with a high prismatic epithelium with a basal arrangement of nuclei, the cytoplasm of cells contains mucus. Often, reserve (combined) cellular elements are often found under the prismatic epithelium. Two types of epithelium - multi-layered flat and prismatic - contact in the area of the external uterine throat. In smears, prismatic epithelial cells are usually found, single metaplastic cells, mucus (in the mucous tube of leukocytes can be very much - up to 60-70 in the field of vision).

[1], [2], [3], [4], [5], [6], [7], [8], [9]