Gardnerella: What Is It, Symptoms, Causes & Treatment

October 2022
  1. Causes
  2. Symptoms
  3. Diagnosis
  4. Treatment

Gardnerella vaginalis and Gardnerella mobiluncus are two types of bacteria that are a normal part of the vaginal flora. However, when they overgrow or overmultiply, they can cause an infection, which is most commonly known as bacterial vaginosis, or BV. BV is characterized by production of a gray-white discharge and a strong, foul odor.

Treatment is completed with antibiotics, such as oral metronidazole or clindamycin, or with ointments that are applied directly to the vagina. In more mild cases, adequate genital hygiene can eliminate the infection.

Gardnerella infection occurs more frequently in women, as the bacterium is part of the normal vaginal microbiota, but men can also be infected through unprotected sex with an infected partner.

Gardnerella causes

There is no specific cause for this type of infection, however, it is more common in women with risk factors such as those with multiple sexual partners, smokers, those who vaginally douche, or those who use an IUD as a contraceptive method.

Genital Gardnerella infection isn’t considered to be an STI (sexually-transmitted infection).  The disease's incubation period is 2 to 21 days, which is the time that the bacteria is present before symptoms appear.

Gardnerella symptoms

Gardnerella can present differently in men and women, with one or more of the following symptoms:

Symptoms in womanSymptoms in man

White or grayish discharge

Redness in the foreskin, glans or urethra
Small blisters on the vagina

Pain when peeing

Foul-smelling odor that worsens after unprotected sex

Itchy penis

Pain during sex

Yellowish discharge from the urethra

It is normal for men with a Gardnerella infection to be asymptomatic. and therefore treatment is not always necessary. However, if infections recur frequently in a woman, the doctor may opt to treat her sexual partner as well, as a couple can reinfect and transmit the infection back and forth through unprotected sex.

In addition, if the infection occurs simultaneously with other bacteria, women may experience inflammation in the uterus and fallopian tubes, which can lead to infertility if treatment is not completed.

How it is diagnosed

The diagnosis of the infection can be done in a gynecological or family doctor office. The doctor will assess for signs of infection, especially for changes to discharge or odor. To confirm a diagnosis, the doctor may also recommend a vaginal culture, in which vaginal discharge is collected with a swab and sent to the laboratory for microbiological analysis.

Through a culture, it it is possible to confirm the exact bacteria responsible for the infection and this should be a reference for guiding treatment.

For men, the diagnosis should be confirmed by the urologist, following evaluation of symptoms and assessment of penile dysfunction.

Treatment options

Gardnerella infection is easy to cure, and treatment is usually completed with oral antibiotics, such as metronidazole, secnidazole, or clindamycin. Ointments can also be prescribed, and they should be applied to the genital area.

Generally,  treatment with an oral antibiotic lasts about 7 days,, or 5 days for the ointments. During this time, ensure you are performing adequate genital hygiene (e.g. washing only the external genital area with soap that is pH neutral or appropriate for the area. See how else bacterial vaginosis can be treated. 

With pregnancy, treatment should only be done with oral antibiotics, under the supervision of the obstetrician. Adequate genital hygiene is also advised. The doctor may also evaluate alternative birth control options if the infection is related to IUD use. 

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Edited by Tua Saude editing team in October 2022. Medical review completed by Dr. Sheila Sedicias - Gynecologist in November 2018.
Medical review:
Dr. Sheila Sedicias
Gynecologist
Physician graduated in Mastology and Gynecology by UFPE in 2008 and member no. 17459 of CRM-PE, Brazil.