Bacterial Vaginosis (BV) 

Posted August 2009


Bacterial vaginosis (BV) is a clinical syndrome that results from replacement of the protective H2O2-producing lactobacilli in normal vaginal flora with high concentrations of anaerobes, Gardnerella vaginalis, and mycoplasmas. The cause of this microbial alteration and concomitant increase in vaginal fluid pH is not well understood. Although a specific sexually transmitted pathogen has not been identified, women are at higher risk for BV when they have multiple sex partners or a new sex partner.1

BV has been associated with increased risk of acquisition and transmission of HIV,2-7 and HIV-infected women may have more severe or persistent BV.8,9 BV is also associated with adverse outcomes in pregnancy (see Section V. Treatment of Bacterial Vaginosis in Pregnant Women).

Characteristics of Bacterial Vaginosis in HIV-Infected Women

  • May persist longer than in women not infected with HIV, especially in HIV-infected women with CD4 <200 cells/mm3
  • May have more severe presentation in HIV-infected women with CD4 ≤200 cells/mm3
  • Treatment regimens are the same for HIV-infected and non-HIV-infected women
  • No difference in prevalence compared to women not infected with HIV

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The presentation of BV in HIV-infected women does not differ from that in women who are not infected with HIV. BV is often asymptomatic. When symptomatic, it is usually noted as a malodorous (“fishy”) vaginal discharge. In contrast to trichomoniasis or candidiasis, inflammation of vaginal or external tissues and painful symptoms such as dysuria and dyspareunia are uncommon. The symptoms may be more apparent during menses or after intercourse when vaginal pH is higher. Asymptomatic endocervicitis caused by BV can occur but is rare; purulent cervicitis should prompt evaluation for another etiology, such as gonorrhea or chlamydia. BV has high rates of persistence and recurrence in HIV-infected women and women who are not infected with HIV, despite appropriate treatment.

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A history of vulvar and vaginal symptoms should be obtained on all women presenting for care including: (AIII)

  • Changes in vaginal discharge/vaginal malodor
  • Vulvovaginal irritation, pruritus, burning, swelling
  • Dyspareunia, dysuria

Amsel’s criteria should be used to diagnose BV. Positive diagnosis requires the presence of three of the following four criteria: (AII)

  1. Homogeneous thin white discharge coating the vaginal walls
  2. Clue cells present on microscopy of vaginal saline preparation
  3. Vaginal fluid pH >4.5
  4. Positive whiff test (fishy odor of vaginal discharge with or without the addition of 10% KOH)

Several commercially available tests have been developed recently and may be clinically useful; however, few published data exist on their performance, and none of the tests is currently FDA-approved. Although one study in HIV-infected women demonstrated that quantification of Lactobacilli, G vaginalis, and Mycoplasma hominis by PCR resulted in superior sensitivity to diagnosis than Amsel’s criteria alone,10 this is not the standard for evaluation and diagnosis in HIV-infected women. Culture of G vaginalis (invariably present in BV) is too nonspecific to be used for diagnosis of BV.

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HIV-infected women with symptomatic bacterial vaginosis who are not pregnant should be treated with the metronidazole or clindamycin regimens specified in Table 1. (AI)

HIV-infected women with asymptomatic bacterial vaginosis should not be treated. (AI)

Patients with symptomatic BV should be treated with one of the recommended metronidazole regimens (see Table 1). The regimens in Table 1 are equally efficacious. Once-daily intravaginal metronidazole gel has been shown to have a cure rate equivalent to twice-daily use. Oral metronidazole 2 g as a single dose has the lowest efficacy for BV and is no longer recommended.11 Intravaginal clindamycin cream and ovules are comparable to each other.12 Metronidazole 750 mg extended release (once daily for 7 days) and single-dose clindamycin cream are FDA-approved for treatment of BV, but no comparative data have been published. Re-establishing normal Lactobacillus flora is often unsuccessful, and treatment failures are common.

Clinicians should consider screening and treating asymptomatic women who are undergoing invasive gynecologic procedures, including surgery and placement of IUDs. Treatment with metronidazole prior to total abdominal hysterectomy has been demonstrated to reduce the risk for vaginal cuff infections,13 and treatment with metronidazole prior to induced abortion may reduce the risk for post-operative upper genital tract infection.14,15 Studies on other gynecologic surgical procedures have not been performed.

Table 1: Recommended Regimens for Treatment of Bacterial Vaginosis in Non-Pregnant HIV-Infected Women
Metronidazole* 500 mg PO bid for 7 days
Metronidazole gel,* 0.75%, one full applicator (5 g) intravaginally, once a day for 5 days
Clindamycin cream, 2%, one full applicator (5 g) intravaginally at bedtime for 7 days
Alternative Regimens
Clindamycin 300 mg PO bid for 7 days
Clindamycin ovules 100 mg intravaginally once at bedtime for 3 days
* Patients should be advised not to consume alcohol during treatment with metronidazole. Abstinence from alcohol should continue for 24 h after completion of either oral or intravaginal metronidazole treatment.

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Clinicians should:

  • Screen all HIV-infected pregnant women for bacterial vaginosis at their first prenatal visit (AII)
  • Treat all HIV-infected pregnant women with symptomatic bacterial vaginosis (AI)
  • Treat HIV-infected pregnant women who have asymptomatic bacterial vaginosis and a history of preterm labor (AIII)

Clindamycin cream should not be used to treat bacterial vaginosis in HIV-infected pregnant women; instead, either oral metronidazole or clindamycin should be used (see Table 2). (AI)

Complications of pregnancy associated with BV include preterm premature rupture of membranes, chorioamnionitis, preterm labor, preterm birth, postpartum endometritis, and post-caesarian wound infection.

Some studies have demonstrated a reduction of preterm delivery among asymptomatic women who had a history of preterm delivery and were treated with either clindamycin16 or metronidazole17 during the second trimester. However, other studies have not demonstrated such a reduction.18 A meta-analysis found a reduction of preterm premature rupture of membranes and low birthweight among women with a history of preterm delivery who were treated for asymptomatic BV, although a reduction of preterm delivery was not established.19 Some specialists prefer the use of systemic therapy to treat possible subclinical upper genital tract infections. CDC recommendations for treatment of BV in pregnant women are listed in Table 2.

Table 2: Recommended Regimens for Treatment of Bacterial Vaginosis in Pregnant HIV-Infected Women
Metronidazolea 500 mg PO bid for 7 days
Metronidazolea 250 mg PO tid for 7 days
Clindamycinb 300 mg PO bid for 7 days
a Patients should be advised not to consume alcohol during pregnancy and that, additionally, treatment with metronidazole requires abstention from alcohol. Multiple studies have not demonstrated teratogenic or mutagenic effects of metronidazole.
b The use of clindamycin cream during the second half of pregnancy has been associated with adverse events such as low birthweight and neonatal infection.

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Clinicians should consider both HIV and STI exposures to partners when HIV-infected patients present with a new STI. Clinicians should also assess for the presence of other STIs (see Management of STIs in HIV-Infected Patients). (AIII)

A. Management of HIV Exposure in Partners

Updated March 2012


When HIV-infected patients present with a new STI, clinicians should offer assistance with notifying partners of both the potential HIV and STI exposures or should refer patients to other sources for partner notification assistance (Partner Services in New York State or CNAP in New York City). Partners without confirmed HIV infection should undergo HIV testing at baseline, 1, 3, and 6 months. Confirmatory testing according to New York State regulations must be performed to confirm HIV diagnoses.

Clinicians must report confirmed cases of HIV according to New York State Public Health Law (for more information about required reporting, see

Clinicians should educate patients with non-HIV-infected partners or partners of unknown HIV status to be vigilant for any post-exposure acute HIV symptoms in their partners, such as febrile illness accompanied by rash, lymphadenopathy, myalgias, and/or sore throat (see Diagnosis and Management of Acute HIV Infection). (AIII)

Partners who present within 36 hours of an HIV exposure should be evaluated as soon as possible for initiation of post-exposure prophylaxis therapy (see HIV Prophylaxis Following Non-Occupational Exposure). (AII)

Presentation of a new STI in HIV-infected patients suggests exposure of both HIV and the STI to their partners. In this case, offering HIV non-occupational post-exposure prophylaxis (nPEP) to partners is usually not an option because the period prior to STI symptom onset is usually longer than the 36-hour window for initiating HIV nPEP. Therefore, sequential HIV testing of partners without confirmed HIV infection should be performed for early identification of potential HIV acquisition. However, if a patient with an HIV exposure does present within 36 hours, evaluation for nPEP should occur (see HIV Prophylaxis Following Non-Occupational Exposure).

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B. Management of Bacterial Vaginosis Exposure


Recent studies support the possibility of sexual transmission of bacterial vaginosis.1,20-21 However, routine treatment of male sex partners of women with BV does not affect rates of recurrence and is not recommended. A higher incidence of BV occurs in female sex partners of women with BV than in female partners of women without BV.22 When symptomatic BV is suspected in a female sex partner, the partner should be screened and treated if indicated.

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1. Fethers KA, Fairley CK, Hocking JS, et al. Sexual risk factors and bacterial vaginosis: A systematic review and meta-analysis. Clin Infect Dis 2008;47:1426-1435. [PubMed]

2. Laga M, Manoka A, Kivuvu M, et al. Non-ulcerative sexually transmitted diseases as risk factors for HIV-1 transmission in women: Results from a cohort study. AIDS 1993;7:95-102. [PubMed]

3. Sewankampo N, Gray RH, Wawer MJ, et al. HIV-1 Infection associated with abnormal vaginal flora morphology and bacterial vaginosis. Lancet 1997;350:546-550. [PubMed]

4. Taha TE, Hoover DR, Dallabetta GA, et al. Bacterial vaginosis and disturbances of vaginal flora: Association with increased acquisition of HIV. AIDS 1998;8:1699-1706. [PubMed]

5. Spear GT, St John E, Zariffard MR. Bacterial vaginosis and human immunodeficiency virus infection. AIDS Res Ther 2007;4:25. [PubMed]

6. Rebbapragada A, Howe K, Wachihi C, et al. Bacterial vaginosis in HIV-infected women induces reversible alterations in the cervical immune environment. J Acquir Immune Defic Syndr 2008;49:520-522. [PubMed]

7. Atashili J, Poole C, Ndumbe PM, et al. Bacterial vaginosis and HIV acquisition: A meta-analysis of published studies. AIDS 2008;22:1493-1501. [PubMed]

8. Warren D, Klein RS, Sobel J, et al. A multicenter study of bacterial vaginosis in women with or at risk for human immunodeficiency virus infection. Infect Dis Obstete Gynecol 2001;9:133-141. [PubMed]

9. Jamieson DJ, Duerr A, Klein RS, et al. Longitudinal analysis of bacterial vaginosis: Findings from the HIV epidemiology research study. Obstet Gynecol 2001;98:656-663. [PubMed]

10. Sha BE, Chen HY, Wang QJ, et al. Utility of Amsel criteria, Nugent score, and quantitative PCR for Gardnerella vaginalis, Mycoplasma hominis, and Lactobacillus spp. for diagnosis of bacterial vaginosis in human immunodeficiency virus-infected women. J Clin Microbiol 2005;43:4607-4612. [PubMed]

11. Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep 2006;55(RR-11):1-94. Available at:

12. Sobel J, Peipert JF, McGregor JA, et al. Efficacy of clindamycin vaginal ovule (3-day treatment) vs. clindamycin vaginal cream (7-day treatment) in bacterial vaginosis. Infect Dis Obstet Gynecol 2001;9:9-15. [PubMed]

13. Larsson PG, Carlsson B. Does pre- and postoperative metronidazole treatment lower vaginal cuff infection rate after abdominal hysterectomy among women with bacterial vaginosis? Infect Dis Obstet Gynecol 2002;10:133-140. [PubMed]

14. Larsson PG, Platz-Christensen JJ, Thejls H, et al. Incidence of pelvic inflammatory disease after first-trimester legal abortion in women with bacterial vaginosis after treatment with metronidazole: A double-blind, randomized study. Am J Obstet Gynecol 1992;166(1 Pt 1):100-103. [PubMed]

15. Crowley T, Low N, Turner A, et al. Antibiotic prophylaxis to prevent post-abortal upper genital tract infection in women with bacterial vaginosis: Randomised controlled trial. BJOG 2001;108:396-402. [PubMed]

16. Ugwumadu A, Manyonda I, Reid F, et al. Effect of early oral clindamycin on late miscarriage and preterm delivery in asymptomatic women with abnormal vaginal flora and bacterial vaginosis: A randomised controlled trial.  Lancet 2003;361:983-988. [PubMed]

17. Morales WJ, Schorr S, Albritton J. Effect of metronidazole in patients with preterm birth in preceding pregnancy and bacterial vaginosis: A placebo-controlled, doubleblind study. Am J Obstet Gynecol 1994;171:345-347; discussion 348-349. [PubMed]

18. Carey JC, Klebanoff MA, Hauth JC, et al. Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. National Institute of Child Health and Human Devleopment Network of Maternal-Fetal Medicine Units. N Engl J Med 2000;342:534-540. [PubMed]

19. McDonald HM, Brocklehurst P, Gordon A. Antibiotics for treating bacterial vaginosis in pregnancy. Cochrane Database Syst Rev 2007;(1):CD000262. [PubMed]

20. Schwebke JR. New concepts in the etiology of bacterial vaginosis. Curr Infect Dis Rep 2009;11:143-147. [PubMed]

21. Bradshaw CS, Morton AN, Hocking J, et al. High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence. J Infect Dis 2006;193:1478-1486. [PubMed]

22. Marrazzo JM, Koutsky LA, Eschenbach DA, et al. Characterization of vaginal flora and bacterial vaginosis in women who have sex with women. J Infect Dis 2002;185:1307-1313. [PubMed]

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