Causes

Bacterial vaginosis (BV) is a common cause of abnormal vaginal discharge in women of childbearing age and affects 30% of women globally (1).

BV is a polymicrobial syndrome (dysbiosis) characterised by a profound change in the vaginal microbiota from a lactobacilli dominant state to one with high diversity and quantities of anaerobic bacteria including Gardnerella vaginalis, Atopobium vaginae, Mobiluncus spp, Prevotella spp, and other BV-associated bacteria (BVAB).

There is a rise in vaginal pH, proteolytic enzymes and volatile amines which produce the malodour.

Although there are supporting epidemiological and microbiological data, sexual transmission of BV has not been established.

There is a strong association between acquisition of BV and sexual behaviours including young age of first sex, increased numbers of sex partners, exposure to new sex partners and lack of condom use for penile-vaginal sex (2).

BVAB are present in the urethra and penile skin more often in male partners of women with BV than without, suggesting these bacteria may be exchanged during intercourse (3-6).

In women who have sex with women studies show very high concordance for BV within partnerships and an association with a range of sexual activities (7,8).

Post treatment recurrence of BV has been associated with exposure to an ongoing sex partner and lack of condom use for penile-vaginal sex (9,10).

Clinical presentation

  • Malodour and/or a thin white or greyish vaginal discharge, although up to 50% of women may be asymptomatic.
  • Associated with increased risk of spontaneous abortion, premature labour, chorioamnionitis, postpartum endometritis and pelvic inflammatory disease (PID). An increased risk of PID has been reported following surgical termination of pregnancy (TOP), intra-uterine device (IUD) insertion or other gynaecological instrumentation. An increased risk of BV acquisition and recurrence has been reported following use of the copper IUD (11-12). Refer to PID treatment guidelines.
  • BV is associated with a 2-4 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

Test Site/specimen Comments
Amsel's criteria Vaginal swab

A diagnosis is made if 3 or 4 of the following criteria are present:

  1. Clinician observed vaginal discharge - thin, white or grey, often adherent, homogeneous appearance
  2. Vaginal pH of ≥4.5
  3. The presence of “clue cells” on a Gram stain or wet preparation of high vaginal secretions
  4. Positive amine (whiff) test – if you can smell the malodour on examination this can be recorded as a positive whiff test
Nugent's criteria Vaginal swab

A score of 7-10 is diagnostic of BV, and 4-6 is classified as intermediate flora

Approximately 50% of women with intermediate flora by the Nugent method will have BV by the Amsel's method

At MSHC we recommend using both Amsel's and Nugent's methods for the diagnosis of BV

Notes

There is currently insufficient evidence to support the recommendation of routine screening for BV at the time of insertion of an intrauterine device or surgical termination of pregnancy to prevent PID or endometritis in asymptomatic women (16-18, 19-23) however, where feasible it is reasonable to provide screening and treatment prior to the intervention.

Copper IUDs have been associated with increased risk of BV acquisition and BV recurrence (11-12):

  • The association between hormonal IUD use and BV is unclear
  • If a patient using an IUD develops BV treat as recommended
  • If the patient experiences recurrent BV with a copper IUD consider switching to an alternative method (24)

Management

Index patient

Treatment is predominantly aimed at alleviating symptoms and recurrence

Treatment is indicated in:

  • Symptomatic women
  • Women undergoing an invasive upper genital tract procedure such as termination of pregnancy and insertion of IUD, where feasible, to reduce the risk of PID/endometritis.
  • The benefit of this practice has not been established
  • Asymptomatic women if they request treatment

Condition

Recommended

Comments

Uncomplicated BV in women who are not pregnant

Metronidazole 400mg PO, twice daily for 7 days

OR

Clindamycin 2% intravaginal cream 5g, nightly for 7 nights (not on PBS)*

OR

Metronidazole gel 0.75%, one applicator (5g) intravaginally, daily for 5 days (not on PBS)

Metronidazole can cause nausea and the patient should be advised to have her medication with food and to avoid drinking alcohol whilst on treatment and for 48 hours after completion.

Women should refrain from sex or recommended to use condoms consistently during treatment.

Douching and intravaginal cleaning practices have been associated with a non-optimal vaginal microbiota and should be avoided

Alternative management for uncomplicated BV in women who are not pregnant

Clindamycin 300mg PO, twice daily for 7 days

OR

Metronidazole 2g, PO, stat*

 

There is currently insufficient evidence to recommend the use of intravaginal lactic acid or vaginal probiotics, however research efforts to determine the role of non-antibiotic or adjunctive regimens in BV treatment are underway. One recent trial of a Lactobacillus crispatus vaginal probiotic showed a 15% improvement in cure compared to placebo when administered after antibiotics (15)

Pregnant woman

The same treatment options for non-pregnant women can be used in pregnancy

Treatment is recommended in symptomatic pregnant women to alleviate symptoms.

Two meta-analyses of observational studies reported no significant association between metronidazole exposure and congenital malformations (25). Metronidazole is category B2 but a meta analysis has not demonstrated an association with teratogenic or mutagenic effects in neonates.

Clindamycin is category A. Oral therapy has not been shown to be superior to topical vaginal therapy in pregnancy. Therefore, both the oral and topical regimens recommended in non-pregnant women can be used.

Recurrent BV

Intravaginal metronidazole 0.75% gel 5g twice per week for 4 months (27)

OR

Boric acid (seek specialist advice)

BV recurrence is common with >50% of women experiencing post-treatment recurrence within 3-12 months.

There are limited data available to guide treatment for highly recurrent BV.

Intravaginal boric acid regimens have also been used but have not shown sustained benefit. Boric acid can be accessed via compounding pharmacies. Seek specialist advice if required.

* stat treatments are associated with higher recurrence rates of BV (14)

Sexual partners

Treatment of male sexual partners has not been recommended as 5 of 6 prior published studies indicated no benefit (13):

  • However, systematic review confirmed these trials were systematically flawed and underpowered (13) and new clinical trials of male partner treatment are underway at MSHC to determine the benefit of this intervention.

No trials of female partner treatment have been conducted to inform female partner treatment:

  • However, high concordance for BV is consistently reported within female-female partnerships.
  • Testing of female partners should be offered in order to detect and treat BV in the partner.

There are no published trials to determine whether the treatment of female partners improves BV cure, however treatment of BV in a female partner is commonly practiced by clinicians.

References

  1. High Global Burden and Costs of Bacterial Vaginosis: A Systematic Review and Meta-Analysis. Peebles K, Velloza J, Balkus JE, McClelland RS, Barnabas RV. Sex Transm Dis. 2019 May;46(5):304-311
  2. Early sexual experiences and risk factors for bacterial vaginosis. Fethers KA, Fairley CK, Morton A, Hocking JS, Hopkins C, Kennedy LJ, Fehler G, Bradshaw CS. J Infect Dis. 2009 Dec 1;200(11):1662-70
  3. Bacterial communities of the coronal sulcus and distal urethra of adolescent males. Nelson DE, Dong Q, Van der Pol B, Toh E, Fan B, Katz BP, Mi D, Rong R, Weinstock GM, Sodergren E, Fortenberry JD. PLoS One. 2012;7(5):e3629
  4. The Microbiome Composition of a Man's Penis Predicts Incident Bacterial Vaginosis in His Female Sex Partner With High Accuracy. Mehta SD, Zhao D, Green SJ, Agingu W, Otieno F, Bhaumik R, Bhaumik D, Bailey RC. Front Cell Infect Microbiol. 2020 Aug 4;10:43
  5. Bacterial communities in penile skin, male urethra, and vaginas of heterosexual couples with and without bacterial vaginosis. Zozaya M, Ferris MJ, Siren JD, Lillis R, Myers L, Nsuami MJ, Eren AM, Brown J, Taylor CM, Martin DH. Microbiome. 2016 Apr 19;4:1
  6. Penile Microbiota and Female Partner Bacterial Vaginosis in Rakai, Uganda. Liu CM, Hungate BA, Tobian AA, Ravel J, Prodger JL, Serwadda D, Kigozi G, Galiwango RM, Nalugoda F, Keim P, Wawer MJ, Price LB, Gray RH. mBio. 2015 Jun 16;6(3):e00589
  7. The influence of behaviors and relationships on the vaginal microbiota of women and their female partners: the WOW Health Study. Bradshaw CS, Walker SM, Vodstrcil LA, Bilardi JE, Law M, Hocking JS, Fethers KA, Fehler G, Petersen S, Tabrizi SN, Chen MY, Garland SM, Fairley CK. J Infect Dis. 2014 May 15;209(10):1562-72.
  8. Incubation period and risk factors support sexual transmission of bacterial vaginosis in women who have sex with women. Muzny CA, Lensing SY, Aaron KJ, Schwebke JR. Sex Transm Infect. 2019 Nov;95(7):511-515
  9. High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence. Bradshaw CS, Morton AN, Hocking J, Garland SM, Morris MB, Moss LM, Horvath LB, Kuzevska I, Fairley CK. J Infect Dis. 2006 Jun 1;193(11):1478-8
  10. Recurrence of bacterial vaginosis is significantly associated with posttreatment sexual activities and hormonal contraceptive use. Bradshaw CS, Vodstrcil LA, Hocking JS, Law M, Pirotta M, Garland SM, De Guingand D, Morton AN, Fairley CK. Clin Infect Dis. 2013 Mar;56(6):777-8
  11. Elevated Risk of Bacterial Vaginosis among Users of the Copper Intrauterine Device: A Prospective Longitudinal Cohort Study. Peebles K, Kiweewa FM, Palanee-Phillips T, Chappell C, Singh D, Bunge KE, Naidoo L, Makanani B, Jeenarain N, Reynolds D, Hillier SL, Brown ER, Baeten JM, Balkus JE; , MTN-020/ASPIRE study team. Clin Infect Dis. 2020 Jun 6
  12. Impact of contraceptive initiation on vaginal microbiota. Achilles SL, Austin MN, Meyn LA, Mhlanga F, Chirenje ZM, Hillier SL. Am J Obstet Gynecol. 2018 Jun;218(6):622.e1-622
  13. Systematic review of randomized trials of treatment of male sexual partners for improved bacteria vaginosis outcomes in women. Mehta SD. Sex Transm Dis. 2012 Oct;39(10):822-30
  14. Indications for therapy and treatment recommendations for bacterial vaginosis in non pregnant and pregnant women. Koumans EH et al. Clin Infect Dis 2002 Oct 15: 35 (suppl2): S152-S172
  15. Randomized Trial of Lactin-V to Prevent Recurrence of Bacterial Vaginosis. Cohen CR, Wierzbicki MR, French AL, Morris S, Newmann S, Reno H, Green L, Miller S, Powell J, Parks T, Hemmerling A.N. Engl J Med. 2020 May 14;382(20):1906-1915
  16. Incidence of PID after first trimester legal abortion I women with bacterial vaginosis after treatment with metronidazole: a double blind randomised study. Larsson PG et al. Am J Obstet Gynecol 1992; 166: 100-103
  17. Treatment with 2% clindamycin vaginal cream prior to first trimester surgical abortion to reduce signs of postoperative infection: a prospective, double-blinded placebo controlled multicentre study. Larsson PG et al. Acta Obstet Scan 2000 May; 79 (5):390-96
  18. Antibiotic prophylaxis to prevent post-abortal upper genital tract infection in women with bacterial vaginosis: randomised controlled trial. Crowley T et al. BJOG 2001 April; 108(4):396-402
  19. World Health Organization: Medical eligibility criteria for contraceptive use. Geneva: WHO; 2009
  20. FFPRHC Guidance (January 2004): The copper intrauterine device as long-term contraception. Penney G, Brechin S, de Souza A, Bankowska U, Belfield T, Gormley M, et al. Faculty of Family Planning and Reproductive Health Care Clinical Effectiveness Unit. J Fam Plann Reprod Health Care 2004;30:29–42. 32
  21. FFPRHC Guidance (April 2004): The levonorgestrel-releasing intrauterine system (LNG-IUS) in contraception and reproductive health. J Fam Plann Reprod Health Care 2004;30:99–109
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  23. Best practices to minimize risk of infection with intrauterine device insertion. Caddy S, Yudin MH, Hakim J, Money DM. J Obstet Gynaecol Can. 2014 Mar;36(3):266-27
  24. FSRH Clinical Guideline: Intrauterine Contraception (April 2015, amended September 2019)
  25. Screening for Bacterial Vaginosis in Pregnant Adolescents and Women to Prevent Preterm Delivery: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. Kahwati LC, et al. JAMA. 2020 Apr 7;323(13):1293-1309
  26. Early clindamycin for bacterial vaginosis in pregnancy (PREMEVA): a multicentre, double-blind, randomised controlled trial. Subtil D, et al Lancet. 2018 Nov 17;392(10160):2171-2179
  27. Suppressive antibacterial therapy with 0.75% metronidazole vaginal gel to prevent recurrent bacterial vaginosis. Sobel JD et al. Am J Obstet Gynecol 2006 May; 194 (5): 1283-

Disclaimer

We recognise that gender identity is fluid. In our treatment guidelines, the words and language we use to describe genitals and gender are based on the sex assigned at birth.

The content of these treatment guidelines is for information purposes only. The treatment guidelines are generic in character and should be applied to individuals only as deemed appropriate by the treating practitioner on a case by case basis. Alfred Health, through MSHC, does not accept liability to any person for the information or advice (or the use of such information or advice) which is provided through these treatment guidelines. 

The information contained within these treatment guidelines is provided on the basis that all persons accessing the treatment guidelines undertake responsibility for assessing the relevance and accuracy of the content and its suitability for a particular patient. Responsible use of these guidelines requires that the prescriber is familiar with contraindications and precautions relevant to the various pharmaceutical agents recommended herein.