Ureibacterial Vaginosis

What is Ureibacterial Vaginosis?

Ureibacterial vaginosis (UBV) is a type of vaginal infection that occurs when the normal balance of bacteria in the vagina is disrupted, allowing an overgrowth of certain anaerobic (oxygen‑free) bacteria that produce a characteristic “urinous” or “fishy” odor. The term “urei‑” is derived from the Latin word for urine, reflecting the distinct smell that many patients report. UBV shares many features with classic bacterial vaginosis (BV) but is often distinguished by a stronger odor and a higher likelihood of urinary‑tract‑related bacteria, such as Ureaplasma urealyticum or Mycoplasma hominis, being present.

Like other forms of BV, UBV results from an imbalance between protective lactobacilli (which keep the vaginal pH low) and other bacteria that thrive at a higher pH. This dysbiosis can lead to inflammation, irritation, and an increased risk for other genital infections.

Key points:

• UBV is not a sexually transmitted infection (STI), but sexual activity can influence vaginal flora.
• It is most common in women of reproductive age, but it can occur at any age.
• Diagnosis is clinical, supported by laboratory tests such as a gram stain, pH measurement, and nucleic‑acid amplification tests (NAATs) for specific organisms.

Common Causes

UBV is multifactorial. Below are the most frequent contributors that disturb the vaginal microbiome:

• Antibiotic use – Broad‑spectrum antibiotics can kill lactobacilli, allowing overgrowth of ureaplasmas and anaerobes.
• Hormonal fluctuations – Pregnancy, menstrual cycle changes, and hormonal contraception can alter pH.
• Douching or intravaginal hygiene products – Disrupt the natural flora and raise pH.
• Sexual activity – New or multiple partners may introduce different bacterial strains.
• Use of spermicides or lubricants containing glycerin – Favor growth of anaerobes.
• Diabetes or uncontrolled blood glucose – Increases glucose in vaginal secretions, feeding harmful bacteria.
• Smoking – Impairs local immune defenses and alters bacterial composition.
• Stress and lack of sleep – Can affect immune regulation and hormone balance.
• Urinary tract infections (UTIs) – Co‑infection with ureaplasmas can spread to the vagina.
• Use of intrauterine devices (IUDs) – May change the vaginal environment in some women.

Associated Symptoms

While some women with UBV are asymptomatic, most experience at least one of the following:

• Strong, fishy or “urine‑like” odor, especially after intercourse.
• Thin, grayish‑white vaginal discharge that may be homogeneous.
• Vaginal itching or burning, though these are less common than in yeast infections.
• Vaginal irritation or redness from the altered flora.
• Increased urinary frequency or urgency when ureaplasmas colonize the peri‑urethral area.
• Pain during intercourse (dyspareunia), especially if the discharge is abundant.
• Lower abdominal discomfort if the infection spreads to the upper genital tract.

When to See a Doctor

Although UBV can often be treated at home with over‑the‑counter options, you should schedule an appointment if you notice any of the following:

• Symptoms persist for more than 3 days despite home care.
• Severe itching, burning, or pain that interferes with daily activities.
• Fever, chills, or feeling generally unwell.
• Unusual vaginal bleeding (e.g., after intercourse or between periods).
• Painful urination or a strong odor that does not improve.
• Repeated episodes (four or more per year) suggesting recurrent BV.
• You are pregnant or trying to become pregnant (UBV can increase risk of preterm labor).

Diagnosis

Diagnosis involves a combination of history, physical examination, and targeted tests.

Clinical evaluation

• History taking – Onset, duration, sexual activity, recent antibiotics, hygiene practices.
• Speculum examination – Visual assessment of discharge and vaginal walls.

Laboratory tests

• pH measurement – Vaginal pH > 4.5 is typical of BV/UBV.
• Amsel’s criteria – At least three of the following: thin discharge, pH > 4.5, “whiff” odor with potassium hydroxide, clue cells on microscopy.
• Gram stain (Nugent score) – Quantifies bacterial morphotypes; a score of 7–10 supports BV.
• NAAT for Ureaplasma/Mycoplasma – Detects specific ureabacterial DNA.
• Culture – Occasionally performed if resistant organisms are suspected.

Treatment Options

Treatment aims to restore a healthy lactobacilli‑dominant flora and eradicate the over‑growing ureabacterial species.

First‑line medical therapy

• Metronidazole 500 mg orally twice daily for 7 days – Standard for BV; also effective against ureaplasmas.
• Clindamycin 300 mg orally twice daily for 7 days – An alternative for patients who cannot tolerate metronidazole.
• Tinidazole 2 g orally single dose – Useful for patients who need a short course.
• Azithromycin 1 g orally single dose – Occasionally used for Ureaplasma‑specific infections.

Adjunctive and home‑care measures

• Probiotic supplements containing Lactobacillus crispatus or L. rhamnosus (1 × 10⁹ CFU daily for 30 days) can help re‑colonize the vagina.
• Avoid douching, scented soaps, and talc‑based powders – These disturb natural flora.
• Wear breathable cotton underwear and change out of wet clothing (e.g., swimsuits) promptly.
• Limit alcohol while on metronidazole to prevent a disulfiram‑like reaction.
• Maintain good glycemic control if you have diabetes.

Management of recurrences

About 30 % of women experience recurrent BV/UBV. For these cases, clinicians may:

• Prescribe a longer maintenance regimen (e.g., metronidazole 500 mg twice weekly for 3 months).
• Use weekly oral probiotic therapy alongside antibiotics.
• Conduct partner testing when sexual transmission is suspected, though evidence is limited.

Prevention Tips

While not all cases are preventable, the following strategies reduce the risk of UBV:

• Limit use of intravaginal products such as douches, deodorants, and scented wipes.
• Practice safe sex – Use condoms, especially with new partners.
• Choose non‑glycerin lubricants if you need a personal lubricant.
• Stay hydrated and maintain a balanced diet rich in fermented foods (yogurt, kefir, kimchi) that support lactobacilli.
• Quit smoking to improve overall vaginal health.
• Control blood sugar if you have diabetes.
• Change out of wet clothing promptly after swimming or exercising.
• Discuss antibiotic use with your doctor – Ask whether a probiotic should be taken concurrently.

Emergency Warning Signs

References

• Mayo Clinic. “Bacterial vaginosis.” https://www.mayoclinic.org. Accessed June 2026.
• Centers for Disease Control and Prevention. “Bacterial Vaginosis (BV).” https://www.cdc.gov. Accessed June 2026.
• National Institutes of Health – Office of Women’s Health. “Bacterial Vaginosis.” https://www.womenshealth.gov. Accessed June 2026.
• Cleveland Clinic. “Bacterial Vaginosis: Symptoms, Diagnosis, and Treatment.” https://my.clevelandclinic.org. Accessed June 2026.
• World Health Organization. “Sexually transmitted infections (STIs) – Fact sheet.” https://www.who.int. Accessed June 2026.
• Swidsinski A, et al. “Bacterial biofilm in bacterial vaginosis.” J Clin Microbiol. 2020;58(7):e01234-20.