Bacterial Vaginosis

Cause

A polymicrobial clinical syndrome caused by a profound change in vaginal microbiota from a Lactobacillius dominant state to one with high diversity and loads of anaerobic bacteria including Gardnerella vaginalis, Atopobium vaginae, Mobiluncus spp, Prevotella spp, and other BV-associated bacteria (BVAB). This change is accompanied by a rise in vaginal pH and increased amines which produce odour. Studies have identified a polymicrobial biofilm adherent to vaginal epithelial cells of women with BV which is absent in controls.

Clinical presentation

Symptoms

Offensive ‘fishy’ vaginal discharge

Thin white homogenous discharge

Can cause mild vulval irritation

Complications

Bacterial vaginosis is associated with increased risk of spontaneous abortion, premature labour, chorioamnionitis, postpartum endometritis and pelvic inflammatory disease (PID); especially following termination of pregnancy (TOP), intra-uterine device (IUD) insertion or other instrumentation). BV is associated with a 2-3 fold increased risk of acquiring STIs including chlamydia, gonorrhoea, herpes simplex type 2 and HIV infection, and increases the risk of HIV transmission to male partners.

Diagnosis

The diagnosis of BV is usually made in clinical settings using the Amsels or modified Amsels criteria;
A diagnosis is made if 3 or 4 of the following criteria are present:
1. Thin white/grey homogenous discharge –
2. Vaginal fluid raised pH (pH>4.5) – using pH paper
3. Genital malodour
4. Clue cells on gram stain – this last criterion will be able to be reported by the laboratory on the slide collected below.

Test	Site/Specimen	Consideration
Microscopy of high vaginal smear	High vaginal swab	In general practice, prepare a non-stained microscopy slide at the bedside and send to the laboratory with a request for Gram stain and microscopy.
Whiff test	Vaginal fluid	Odour during examination indicates a positive whiff test.
pH	Vaginal fluid	Normal vaginal pH < 4.5. pH >4.5 indicative of bacterial vaginosis.

Specimen collection

Clinician collected | Self-collection
 

See STI Atlas for images.

Management

Principal Treatment Option
Situation	Recommended	Alternative
Symptomatic bacterial vaginosis	Metronidazole 400mg PO, BD with food for 7 days.  OR Metronidazole 0.75% gel 5g, intravaginally nocte for 5 nights (not on PBS).  OR Clindamycin 2% vaginal cream 5g, intravaginally nocte for 7 days (not on PBS).  OR Clindamycin 300mg PO, BD for 7 days.	Metronidazole 2g PO, stat. OR Tinidazole 2g PO, stat.
Women undergoing gynaecological procedures	Metronidazole 400mg PO, BD with food for 5 days.  OR  Clindamycin 300mg PO, BD for 7 days.	Metronidazole 2g PO, stat. OR Tinidazole 2g PO, stat.

Treatment advice

Treatment is predominantly aimed at alleviating symptoms and recurrence. Treatment is indicated in:

1. symptomatic women

2. Women undergoing an invasive upper genital tract procedure. (Oral treatment is recommended)

3. women requesting treatment

• If a patient has an intrauterine device (IUD), leave IUD in place and treat as recommended. Seek specialist advice as needed.
• Stat dose and short duration regimens are associated with higher rates of recurrence.
• Recurrence is common

Other immediate management

• Avoid vaginal douching
• Contact tracing is not required.

Special treatment situations

Situation	Recommended
Breastfeeding	Consider intravaginal treatment. Metronidazole may affect taste of breast milk; avoid high doses in breastfeeding.
Pregnant women  Aciclovir B3 Hydrocortisone A Amoxycillin A Imiquimod B1 Azithromycin B1 Itraconazole B3 Benzathine Penicillin A Ivermectin B3 Bioallethrin B2 Lignocaine A Cefotaxime B1 Metronidazole B2 Ceftriaxone B1 Permethrin B2 Ciprofloxacin B3 Piperonyl butoxide  B3 Clindamycin A Podophyllotoxin D Clotrimazole A Probenecid B2  Doxycycline D Procaine Penicillin  A Erythromycin A Tinidazole B3 Famciclovir B1 Valaciclovir B3 Fluconazole D     For more information go to the Therapeutic Goods Association's Prescribing medicines in pregnancy database and/or seek specialist advice.	Treatment for pregnant women is the same as the principle treatment options for non-pregnant women. Treatment is recommended for all pregnant women with symptoms, although the evidence is conflicting in terms of the benefits of treatment on the outcomes of pregnancy. Women undergoing termination of pregnancy should be treated to reduce risk of post-termination PID.
Allergy to principal treatment choice	If allergy to nitroimidazoles, use clindamycin.
Alcohol	Alcohol should be avoided with metronidazole use due to the possibility of a disulfiram-like action. There are no data on the risks of  alcohol with intravaginal metronidazole gel, but it is not recommended at present.
Intravaginal preparations	May affect condom integrity.

Contact tracing

• Contact tracing is not required
• There is currently no evidence to support routine treatment of male sexual partners
• As concordance for bacterial vaginosis is high in female partnerships, assessment of female partners is recommended (women who have sex with women (WSW)).

Follow up

Not required.

Test of Cure (TOC): Not required

Retesting: If symptoms persist or recur, as it is important to confirm diagnosis and establish a pattern. Consider testing for other STIs, if not undertaken at first presentation, or retesting post the window period.

Auditable outcomes

• 100% of symptomatic patients are treated
• 100% of women undergoing an invasive upper genital tract procedure are treated.