What is the transmission path?

Bacterial vaginosis is not a transmissible infection in the true sense. Unlike HIV or syphilis, for example, it is not transmitted directly through sexual intercourse. Various factors, including frequent sexual intercourse or frequently changing sexual partners, lead to an imbalance in the vaginal flora.

Above all, bacteria such as Gardnerella vaginalis, which are found in the natural vaginal flora anyway, are the cause of bacterial vaginosis. These pathogens are not transmitted to the woman from outside. Therefore, in the case of bacterial vaginosis, in contrast to a chlamydia infection, for example, there is no need to treat the partner as well.

Bacterial vaginosis occupies a special position among gynaecological infectious diseases. Unlike infection with Chlamydia or HP viruses and trichomonads, bacterial vaginosis is not directly contagious. It is true that often the woman’s sexual partner also carries the causative germ, namely Gardnerella vaginalis.

However, this germ is usually without any disease value. It is also called an optional pathogen. This means that the pathogen can cause a disease, but does not have to. A bacterial vaginosis is therefore basically not contagious. Nevertheless, protected sexual intercourse should be practised as part of the treatment and also with a view to the prophylaxis of other diseases, especially with changing sexual partners.

Diagnosis

For the diagnosis of a bacterial vaginosis the so-called blackbird criteria exist. At least three of the four blackbird criteria must be fulfilled in order to be allowed to make the diagnosis “bacterial vaginosis”. The blackbird criteria are determined by means of various examinations.

One criterion is the presence of increased low-viscosity or foamy, grey-white to pale fluorine. The gynaecologist sees this fluorine during the vaginal examination. Furthermore, a reddening of the vagina may be noticeable.

The second criterion is the fishy smell of the vagina. This can be enhanced by the amine test. In this test, the doctor drips a solution of potassium hydroxide solution onto some smear material from the vagina.

The fishy smell is intensified by the lye. With the help of a pH strip, the gynaecologist also determines the pH value on the inner wall of the vagina. If this is above 4.5, another blackbird criterion is fulfilled.

To examine the last blackbird criterion, a smear from the inner vaginal wall is examined under the microscope. There you will find so-called key or clue cells. These cells are scoured cells from the vaginal surface, which are colonised with bacteria.

In unclear cases, a bacterial culture can also be applied. For this, a smear is taken from the vagina and the bacteria are allowed to grow on special culture media. As a routine examination, however, this examination is not of any significance in bacterial vaginosis.