What is gardnerella vaginalis?|
Bacterial vaginosis is the most common cause vaginal discharge and accounts for around 50% of total vaginal infections. Gardnerella vaginalis is one of the types of bacteria, which can cause bacterial vaginosis in women i.e. inflammation of the vagina accompanied by discharge, irritation and itching.
Other organisms that are known to cause gardnerella like symptoms are:
- Mycoplasma hominis
The normal bacterial flora in the vagina can be classified into two broad categories (i.e. aerobic and anaerobic). Infection by anaerobics strains also give gardnerella like symptoms and therefore bacterial vaginosis is also called gardnerella vaginitis.
Who gets infected with gardnerella vaginalis?
Gardnerella vaginalis is found in 50% of normal healthy women without causing any symptoms or adverse affects. Those that get infected are women of normal childbearing age (i.e. from 15 to 45years of age approximately). Although the prevalence rate is around 15-25% among the total female population in their reproductive age the prevalence rate among women who attend STD (sexually transmitted diseases) clinics ranges from 32-64% for the same age group.
Despite its high prevalence among sexually active women, it is not sexually transmitted the same way as STD's such as gonorrhoea and is not medically classified under that group. Invasive procedures such as endometrial biopsy, hysterectomy or intrauterine devices (IUD's) may increase the chance of infection with this organism. Men usually have no symptoms and they just act as carriers.
How does a person get infected?
This organism "can" be transmitted by sexual activity, although not always as its increased presence is also found in sexually non-active young women as well. The normal vagina has a usual set of bacterial flora in it and clinical symptoms are usually a result of a change in distribution and types of the normal flora.
Change in sexual partners, menopause, lowered immune systems and diabetes mellitus are recognised as potential risk factors associated with infection. The following conditions are potential causes of a gardnerella vaginosis:
- Conditions that increase genital moisture and warmth such as nylon underwear.
- Any illness which lowers the body immune function.
- Drop in general hygiene.
Signs and symptoms of infection
There will be an abnormal grey-white to yellowish vaginal discharge with a musty or fishy odour, noticeably after intercourse or during menses. The discharge looks thin and homogeneous and tends to coat the vaginal walls. Exact confirmation of the presence of gardnerella vaginalis cannot be based on symptoms alone since many other bacterial and non-bacterial causes (e.g. allergies from spermicides, fabric softeners) can result in the same manifestation of symptoms.
In a normal subject the pH of the vagina is low but in the case of infection the vaginal pH would be increased due to decreased acidity. The pH value would be greater than 4.5.
The absence of normal lactobacilli points towards infection with another type of microorganism.
For laboratory diagnosis a swab from the vagina is taken. The detection of the organism itself under microscopic examination is a strong finding where the vagina will show numerous "clue" cells (vaginal lining cells coated with gardnerella vaginalis). These cells have a granulated surface and blurred cell margins whereas normal vaginal epithelial cells have sharp edges. To clinically confirm diagnosis more than 20% of the cells in the mount should be clue cells. Gardnerella vaginalis appears negative in a gram stain. But the other organisms causing vaginitis have different gram stain properties.
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