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Bacterial Vaginosis

Practice Essentials

Bacterial vaginosis (BV), or nonspecific vaginitis, was named because bacteria are the etiologic agents and an associated inflammatory response is lacking. Many studies have demonstrated the relation of Gardnerella vaginalis with other bacteria in causing BV, such as Lactobacillus, Prevotella, and anaerobes, including Mobiluncus, Bacteroides, Peptostreptococcus, Fusobacterium, Veillonella, and Eubacterium. Mycoplasma hominis, Ureaplasma urealyticum,Streptococcus viridans, and Atopobium vaginae have also been associated with BV.

Signs and symptoms

Typical symptoms of BV include the following:

Vaginal odor (the most common, and often initial, symptom of BV); often recognized only after sexual intercourse

Mildly to moderately increased vaginal discharge

Vulvar irritation (less common)

Dysuria or dyspareunia (rare)

Risk factors that may predispose patients to BV include the following:

Recent antibiotic use

Decreased estrogen production of the host

Wearing an intrauterine device (IUD)

Douching

Sexual activity that could lead to transmission (eg, having a new sexual partner or a recent increase in the number of sexual partners)

Physical findings in BV may include the following:

Gray, thin, and homogeneous vaginal discharge, which adheres to the vaginal mucosa

Increased light reflex of the vaginal walls, but typically with little or no evidence of inflammation

Normal-appearing labia, introitus, cervix, and cervical discharge

In some case, evidence of cervicitis

See Clinical Presentation for more detail.

Diagnosis

In addition to the history and vaginal examination, microscopic examination is vital to the clinical diagnosis of BV.

On microscopic examination of the discharge, demonstration of 3 of the following 4 Amsel criteria is considered necessary to diagnose BV most accurately
:

Demonstration of clue cells on a saline smear (the most specific diagnostic criterion)

A pH greater than 4.5 (up to 90% of patients)

Characteristic thin, gray, and homogeneous discharge

Positive whiff test (up to 70% of patients)

Nugent’s criteria may be used to quantify or grade bacteria via Gram staining of vaginal samples. These criteria evaluate the following 3 types of bacteria and assign scores to each as shown:

Lactobacillus (score, 0-4)

Bacteroides/Gardnerella (score, 0-4)

Mobiluncus (score, 0-2)

Total scores are calculated and interpreted as follows:

0-3: Normal

4-6: Intermediate bacterial count

7-10: BV

See Workup for more detail.

Management

General principles of treatment of BV include the following:

Antibiotics are the mainstay of therapy

Data on the efficacy of dietary supplementation with Lactobacillus (acidophilus) are conflicting

Asymptomatic women with G vaginalis colonization do not need treatment

BV occurring in pregnant women should be treated

Treatment before cesarean delivery, total abdominal hysterectomy, or insertion of an IUD is also recommended

Uncomplicated cases typically resolve after standard antibiotic treatment

BV that does not resolve after one course of treatment may be cured by giving a second course of the same agent or by switching to another agent (eg, from metronidazole to clindamycin or from clindamycin to metronidazole)

Some women with recurrent BV may benefit from evaluation or treatment of G vaginalis colonization in their sexual partner (controversial)

Patients should be advised to stop douching or using bubble bath or any other over-the-counter vaginal hygiene products

Patients should wash only with hypoallergenic bar soaps or no soap at all and should avoid liquid soaps and body washes

Surgery is not indicated

Testing for other infections (eg, N gonorrhoeae, C trachomatis, or herpes simplex virus [HSV]-1) may be appropriate

Therapy with metronidazole or clindamycin may alter the vaginal flora and predispose the patient to development of vaginal candidiasis

See Treatment and Medication for more detail.

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